How To Tell If It's Really Titanium

With the growing popularity of titanium, some disreputable merchandisers are passing off other materials as the more expensive metal. Popular Science looks at a surefire way to prove what that credit card/crowbar/ring is really made of. "Hold any genuine titanium metal object to a grinding wheel (even a little grindstone on a Dremel tool will do), and it gives off a shower of brilliant white sparks unlike any softer common metal. The sparks are tiny pieces of cut titanium--the friction of the grinder heats them till they burn white-hot. Hold a grindstone to the shackle of a "titanium" padlock from Master Lock, however, and you'll instead see the telltale fine, long, yellow sparks of high-carbon steel."

Comments

is there a better way?

[pwizard2]

The method in TFA sounds like it would really scratch up whatever you're trying to test. Is there a way to run a test without damaging the object?

Re:is there a better way?

[TheBearBear]

I'm not a scientist, but maybe you user laser on the object at a defined temperature to see what kind of metal it is? I'm pretty sure they've been doing this stuff for a while!

Re:is there a better way?

[Dan East]

Yes, there is a better way, and your concern about damaging expensive objects - particularly jewelry - is quite justified. Simply send the object to one of my two testing centers (conveniently covering both hemispheres - one is located in Russia, the other in Africa) and we will send you a full report of the object's composition.

Dan East

Re:is there a better way?

[andyfrommk]

The method in TFA sounds like it would really scratch up whatever you're trying to test. Is there a way to run a test without damaging the object?

apparently It is a pale grey colour with a subtle orange peel texture

Re:is there a better way?

[pilsner.urquell]

If the oxidation is gray it's titanium red (rust) it's Iron. If you put it in salt water and it don't corrode it's titanium if it dose it's iron. An equal amount titanium weighs 45% less than an equal amount of iron (volume). If you can't afford it it's titanium if you can afford it it's iron (point of story). Titanium

Re:is there a better way?

[Anonymous Coward]

If it weighs the same as a duck...

Re:is there a better way?

[ByteSlicer]

A laser spectrometer can do this for you. It will still create microscopic damage though.

Re:is there a better way?

[rs79]

"The method in TFA sounds like it would really scratch up whatever you're trying to test. Is there a way to run a test without damaging the object?"

Titanium is the only metal hydrogen peroxide reacts with.

Grinding titanum in considered very dangerous. It can explode.

Whoever wrote the article is seriously undereducated.

Re:is there a better way?

[noidentity]

Simply send the object to one of my two testing centers and we will send you a full report of the object's composition*.

* We will securely dispose of the object unless you specifically request that we send it back.

Err, wrong thread, sorry.

Re:is there a better way?

[m4cph1sto]

Nah. Fine titanium powder is explosive, due to the high surface area. A solid chunk of titanium should be fine to grind, and any powder generated from grinding should be fully oxidized by the time it cools. Just clean up after you're done.

Still, I'd say the best way to tell would be a simple density measurement (Archimedes Principle). If that's not possible and for some reason this is very important to you, then make a friend at your local university and get it analyzed by some method of x-ray spectroscopy.

Re:is there a better way?

[budgenator]

Titanium can be smooth and polished to a fine surface, it's just a bit more challenging, to get that surface. It's also easy to anodize, the same as aluminum but the thickness of the anodizing has limits. When anodizing Titanium electrolytically, the thickness of the oxide coat, and therefore the color of the coat can be controlled by the voltage, MrTitanium's Introduction to Anodizing Titanium give a good DIY intro for the inquisitive.

Re:is there a better way?

[necro81]

How much are you paying for that service? For $30,000-40,000, you can buy a handheld x-ray fluorescence analyzer. These things got started in testing for lead paint, and now get used to test and check for lots of things - including alloy composition verification. An XRF shines x-rays of a known energy at the test sample, then detects and analyzes the spectrum that is reflected back. Each element has a characteristic x-ray emission spectrum based on the energy of electrons dropping into lower shells. In 10-20 seconds, you can get a really good breakdown of the elements in the test sample.

Re:is there a better way?

[Anonymous Coward]

Titanium is the only metal hydrogen peroxide reacts with. If you test H202 on some steel and end up with some disassociated H+ ions (hint, it happens naturally in light) you actually can make most steels extremely brittle to the point they can and will fail in many applications.

Whoever wrote the article is seriously undereducated. Whoever wrote that post coughrs79cough is seriously undereducated as a real engineer. I hope you are a software guy.

Re:is there a better way?

[GSGKT]

How about x-ray fluorescence spectroscopy (XRF): http://en.wikipedia.org/wiki/X-ray_fluorescence It would not damage the samples, and the energy emitted by iron and titanium are very different to tell them apart. Handheld XRF machines have been used for detecting lead in toys, and it might be useful in this case

Re:is there a better way?

[arivanov]

A good test is with fuming Concentrated Nitric Acid or "royal water" - mix of Nitric Acid with Sulfuric, the one that dissolves gold. It will also dissolve nearly anything else on earth even group 8 noble metals.

Titanium is passivated in it and does not dissolve or show any signs of damage (except in extremely high saturation fuming nitric acid). At the same time it happily dissolves is hidrocloric, hidrofluoric acid. It will also dissolve in sulfuric acid even in low concentrations. IIRC it did not like the strong organic acids either, but I do not recall which dissolve it and which not at the moment (it is been a while since I gave in to the dark side of IT and left chemistry).

Note, that as most commercial titanium is actually various titanium alloys they may get coloured or change their appearance when passivated. Most importantly - if it is titanium it will smile at nitric acid and any strong oxidising agent and shrug it off.

This all is off the top of my head. Check with a good inorganic chemistry book before bringing a flask of something obnoxious to a shop.

Re:is there a better way?

[Anonymous Coward]

FYI, it's "hydro______", i.e. "hydrofluoric"

Re:is there a better way?

[Seto89]

I have bad experience with mixing nitric acid with sulphuric acid.

Especially if you get glycerol involved...


I say better have a fake titanium ring than no hands. But then again, who never wanted to mix explosives?

Re:is there a better way?

[badspyro]

The great man Archimedes may have an idea here...

1)weigh object
2)place object in full container of water
3)mesure displaced water
4)work out if the mass of the ring is higher or lower than the volume of titanium the ring should contain
5)...
6) PROFIT!

Re:is there a better way?

[Mspangler]

x-ray fluorescence. There are portable "guns" that can do this now, for only about $30,000.

The old ones took up a room, had a radioactive source, and the spectrometer had to be cooled with liquid N2.

The modern PMIs are pretty nice. Point at a piece of metal, pull the trigger, and in 5 seconds it tells you if it is 304, 316, C-276, 800HT, or whatever. If the metal is not in the database, then it tells you the elemental makeup so you can look it up, and if it's a real alloy enter it into the database. If it's some odd corrosion product (C-276, but missing some chrome) that can help analyze corrosion problems.

I have one on next year's budget wish list. (And yes, I am a metallurgical engineer.)

Re:is there a better way?

[dbIII]

15% nitric acid in alchol and see if it goes from bright to dull - after grinding a little patch clean of course in which case you'd already get the sparks. Engineers like to break stuff and there's usually a corner somewhere that you can damage slightly.

Re:is there a better way?

[NASA NERD]

I sure hope there is! I dont want to screw up my stuff!

Re:is there a better way?

[Skrapion]

Aluminum is also light-weight, corrosion-resistant, and has grey oxidization, so those may not be the best tests.

Re:is there a better way?

[cshake]

An interesting discovery you will make with such a device is that nearly anything that is painted will show up as having titanium in it. That's because titanium is used to create the white base for most paint. Of course black won't have it.
I have seen this demonstrated by a professor who has one of the X-ray things, pointed it at a textbook and came up with 'mostly titanium' because the paint and ink on the cover was the only part that was metallic, and since titanium makes up most of the metal in paint, it shows up as that. The dangerous part about those is that it will tell you the composition of a metal, you just have to be careful which metal you're pointing it at, since it has very shallow penetration. On a solid block, it will give you the composition of the coating and not the inside.

Wow, a class in materials for a MechE degree will actually teach something?!?

Re:is there a better way?

[Torvaun]

People actually translate aqua regia into "royal water"? I've never encountered it before.

Re:is there a better way?

[arivanov]

My chemistry is quite obviously "not English" so I was translating into English something from another language(s). Apologies.

Anyway, the idea is still the same. You can dip titanium into the nastiest oxidising mix and it will shrug it off.

Re:is there a better way?

[j_sp_r]

Probably the most important is that you learn to know the limitations of your tools!

Re:is there a better way?

[srussia]

The great man Archimedes may have an idea here...

1)weigh object
2)place object in full container of water
3)mesure displaced water
4)work out if the mass of the ring is higher or lower than the volume of titanium the ring should contain
5)...
6) PROFIT!

you forgot 5)Run naked in the streets...
so
6)...
7)PROFIT!

Re:is there a better way?

[berashith]

Exactly my thought. I don't think it would go over too well if my wife found me with my wedding ring in a vice while holding a grinder. The only thing to make it worse would be if I had forgotten the safety goggles again.

Re:is there a better way?

[Keith_Beef]

More dangerous yet, would be to grind aluminium and steel or iron on the same wheel.

Iron oxide powder + aluminium powder -> thermite.

http://en.wikipedia.org/wiki/Thermite

Beef.

Re:is there a better way?

[Actually, I do RTFA]

Titanium is the only metal hydrogen peroxide reacts with.

Other than hydrogen peroxide breaking down in sunlight/over time and being used as one of the components in rocket fuel, there is also the matter that iron is an effective catalyist. Which is why hydrogen peroxide foams when you put it in a cut (red blood cells). Thank you 9th grade biology!

Re:is there a better way?

[Brickwall]

Probably the most important is that you learn to know the limitations of your tools!

Yes, that's been hard for me.. well, actually, not hard for me.. er, never mind.

Re:is there a better way?

[Aardpig]

More specifically, it foams because of catylase (an enzyme) in the blood. I'm not sure if iron plays any role in this...

Re:is there a better way?

[Aardpig]

You've never poured hydrogen peroxide over manganese (a metal)? Boy, you're seriously undereducated....

Re:is there a better way?

[Actually, I do RTFA]

Iron is the catalyst.

Re:is there a better way?

[Aardpig]

OK, but it is far more efficient as catalase (I mispelled it originally), than in simple solution. See http://www.madsci.org/posts/archives/2000-02/950039812.Bc.r.html

Re:is there a better way?

[grrrl]

Actually aqua regia is nitric and hydrochloric acid (3:1) in case anyone is following along... :)

Oh great...

[grassy_knoll]

Think the store will mind if I bring a dremel with grinding wheel to the store with me? For testing purposes of course...

Re:color, texture, weight

[Alaria Phrozen]

Wtf is with these fake links? Do you get money or something for that stupid city?

Good news

[Anonymous Coward]

Apparently my wife's jewelry was all genuine titanium!

Re:Good news

[niceone]

Lock up the dremel before you go to sleep tonight.

Re:Good news

[aliquis]

And now they has emotional value aswell! That of anger, hate, ...

Density test

[Ostsol]

If the object in question is constructed from a single material, then a density test should work. Use water displacement and a scale to determine the volume and mass, respectively. From that you can calculate the density and compare the value to the actual density of titanium. Of course, this won't work if the object merely has titanium components and it cannot be disassembled. . .

Re:Density test

[g0dsp33d]

It still works for electronics though! (you'll prove something is dense)

Re:Density test

[Anonymous Coward]

I DUN GET IT LOL

Re:Density test

[a_claudiu]

If it weights more than a duck ..., hmmm never mind.

Re:Density test

[g0dsp33d]

Its not too hard, you can try it from the comfort of your tub with a toaster.

Re:Density test

[Anonymous Coward]

The density test is easy to do, and only has one difficulty. First get a container bigger than the titanium thing you want to test. The difficult thing is to ensure you are testing ONLY a piece of titanium. For example, some frames for eyeglasses are titanium, but you only want to test the frame, or part of the frame, and not the lenses.
After you have the container, get a second and even larger container. Put the first container inside the second, and Fill the first container with water to the brim. Then dunk the titanium thing. The water that overflows will equal the volume of the object, and will be caught in the second container. You may now measure that volume, by measuring the quantity of overflowed water.
Next, take the titanium thing and weigh it.
Next divide the weight by the volume. some common materials are: Lead, ~11 grams/milliliter (1 milliliter is also 1 cubic centimter); copper, ~9 gm/ml; iron/steel, ~8 gm/ml; titanium, ~4.5 gm/ml; aluminum, You can see that titanium has a different enough value from the others, that it should be accurately identifiable.
Of course, to be really really sure, testing the thing nondestructively, use an X-ray spectrometer. :)

Re:Density test

[Brickwall]

If it weights more than a duck ...

then it's a witch?

a magnet?

[someone1234]

High carbon steel isn't magnetic or what?

Re:a magnet?

[Ceriel Nosforit]

Useful trivia:
Steel is a blend of iron and carbon. Mostly iron, in all its incarnations, and iron is always magnetic.

High-carbon steel is very hard but a bit brittle, while steels with less carbon will usually deform before they crack. There is always a compromise between hardness and toughness.

Re:a magnet?

[Kazymyr]

...iron is always magnetic.

That is a big fallacy. There are some alloys in which iron is around 98-99% which are non-magnetic (think unusual alloying elements like niobium and rhenium).

Re:a magnet?

[Anonymous Coward]

Hey dumbfuck, go stick a magnet on your kitchen sink... Before spouting obvious wrongabilities, check your facts a bit OK shit-for-brains?

Re:a magnet?

[Ceriel Nosforit]

Absolutely fascinating, but iron is an element (Fe), not an alloy.

Re:a magnet?

[Anonymous Coward]

ummm...wow. okay, wow, not sure where to begin here. okaaaaaaaaay, yeaaaaaaaaaah. I'm gonna need you to come in on a saturday...yeaaaaaaah...if you could just start putting the covers on your TPS report, that'd be greaaaaaaat...

Re:a magnet?

[Fex303]

Mostly iron, in all its incarnations, and iron is always magnetic.

You've never tried to stick a magnet to a stainless steel fridge, have you?

Useful trivia: Magnetism is slightly harder than you think.

Re:a magnet?

[LynnwoodRooster]

Nope. Get above 0.15% carbon or so and you lose almost all the magnetic properties of iron. It's one reason that loudspeakers are made with low carbon steel (usually 1006, 1008, or 1010 grade) since you get too much carbon and the flux no longer flows well, meaning you need a LOT more magnet and a higher grade magnet to get the same flux in the gap.

And yes, I am a loudspeaker engineer... ;)

MERRY CHRISTMAS!

Re:a magnet?

[Kreigaffe]

I highly doubt those alloys would be used to replace titanium on any consumer good.

The idea is to cut corners and cost.

Re:a magnet?

[beallj]

Except the statement was in response to a post claiming that steel, an alloy, was magnetic because iron is always magnetic.

Re:a magnet?

[Anonymous Coward]

I like your sense of yourself. No, I mean, truly, I do. Thank you!

Re:a magnet?

[Anonymous Coward]

And a practical example: The winner for strength/durability/ductility for hydraulic lines used in commercial aircraft is Corrosion Resistant Steel (aka Stainless Steel which many variations of hardness). In the wheel well of an aircraft, for example - a tire burst zone, cres is used in lieu of titanium because it can deform more before cracking. And in non-critical areas titanium lines are used for its strength to weight advantages.

Re:a magnet?

[Anonymous Coward]

Also, blood is not magnetic either

Re:a magnet?

[budgenator]

Steel is actually an alloy containing predominately iron, usually has a good amount of precipitated Ferric Carbide crystals , ferric-Carbide in solution with the iron and often trace elements and occasionally minute amounts of pure carbon which is detrimental. The amount of carbide in solution and precipitated greatly controls the physical properties of the metal and is controlled by the heat treatments the steel is exposed to during manufacture.

Re:a magnet?

[budgenator]

Iron isn't always magnetic, when heated to or above it's normalization temperature it loses it's magnetic properties, you can hold a piece of steel suspended with an electrimagnet in a kiln and heat it, when it reaches it's normalization temp it will fall to the kiln floor.

Re:a magnet?

[funfail]

You've never tried to stick a magnet to a stainless steel fridge, have you?

That's because they mislead the customer by using titanium instead of steel in fridges.

Re:a magnet?

[the eric conspiracy]

Depends on the type of stainless. Austentitic is not ferromagnetic, while martensitic is.

Re:a magnet?

[Anonymous Coward]

For example: stainless steel is non-magnetic.

Re:a magnet?

[Oswald]

Very witty. Sorry, no mod points.

Re:a magnet?

[Ceriel Nosforit]

Well yes, but since the reply was nitpicking, I decided to respond with more nitpicking in a vain attempt to show how useless it was. My original reply was, I thought obviously, a useful thumb rule for a person who didn't know much about metals and metal alloys. It was was not a wikipedia entry; by experts for experts. I'd bore the OP to an early grave if I tried to tell him about the finer points of metallurgy.

And why the heck need I waste all this text explaining myself to you anyway? It's all evident... :\

Re:a magnet?

[necro81]

Most steels are magnetic to various degrees. However, when designing some stuff that would be used in an MRI suite, I did some research and found that some grades of stainless steel - specifically, 300-series stainless steels (302, 304, 316, etc.) - are more or less nonmagnetic. They can't be used inside the bore of the scanner, but that's mostly because it screws up the uniformity or the magnetic and RF fields necessary for imaging. This was a handy discovery for me, because sometimes aluminum and plastics aren't strong enough, and titanium is a lot harder to work with.

Re:a magnet?

[Anonymous Coward]

Mod parent up - try a magnet on stainless fridge!

Re:a magnet?

[Anonymous Coward]

they would probably use aluminum. Light, stainless and non-magnetic.

Re:a magnet?

[Anonymous Coward]

Iron is the primary element in stainless steels, which generally do not rust and in many ways could resemble titanium
Austenitic stainless steels in particular are not magnetic, except some maybe slightly after coldworking. Those would be the 300 series of allows: 302/303/304/305/309/316, etc.

Re:a magnet?

[Minstrel Boy]

Dive knives are available in both titanium and rhodium/steel alloys, because non-magnetism is a desirable feature.

KeS

Re:a magnet?

[Gordonjcp]

And in fact, some soldering iron thermostats use this property. When the iron is cold, a magnet pulls the contact closed. Once it heats above the Curie point, the magnet lets go and the contact breaks.

Re:a magnet?

[Mercedes308]

While what you say is true in as far as magnets won't stick to it, it still has a very weak magnetic field. One of the factory's I'm involved with uses a metal detector that detects any pieces of stainless steel that may be in the product.

Re:a magnet?

[Grishnakh]

Why on earth would you want a titanium knife? Titanium is very light for its strength, but it's not hard enough to hold a decent edge. It's absolutely useless for blades.

Re:a magnet?

[stasike]

You do not need a divers knife to hold an edge. You only use it in emergencies.
Titanium does not rust. Even stainless steel will rust if you use it for a frequently used divers knife.

Re:a magnet?

[Anonymous Coward]

s/it's/its/g

Re:a magnet?

[Anonymous Coward]

And why the heck need I waste all this text explaining myself to you anyway? It's all evident... :\ Because your "useful rule of thumb" was useless and obviously wrong, and when corrected, you went nuts. Jeez.

The reply wasn't nitpicking, since, as per other entries in the thread there are many rather common steel variants that are not particularly magnetic. You might have a point if it were just exotic alloys that normal persons indeed need not to know about, but as it is, you're just spouting shit.

Re:a magnet?

[Anonymous Coward]

You've never tried to stick a magnet to a stainless steel fridge, have you?

To be fair, maybe he has. When I went fridge shopping, most "stainless steel" fridges the salesmen were trying to pawn off were magnetic.

Maybe they were this stuff,

Martensitic stainless steels are not as corrosion resistant as the other two classes, but are extremely strong and tough as well as highly machineable, and can be hardened by heat treatment. Martensitic stainless steel contains chromium (1214%), molybdenum (0.21%), zero to less than 2% nickel, and about 0.11% carbon (giving it more hardness but making the material a bit more brittle). It is quenched and magnetic. It is also known as "series-00" steel.
http://en.wikipedia.org/wiki/Stainless_steel

Re:a magnet?

[leenks]

My Weller iron has one of these. Unfortunately, when they go wrong you end up with the whole metal shaft of the iron going bright orange :((

Re:a magnet?

[cerberusss]

And yes, I am a loudspeaker engineer... ;)

MERRY CHRISTMAS!

Could you turn that down please? :P

Re:a magnet?

[DougF]

Actually, titanium holds an edge very well. I've used my diver's knife with a titanium blade for 7 years and have not had to sharpen it once. It's still just as sharp as the day I bought it. I dive several times a year and use it to dig for shark's teeth, as a tool, and for protection. Not a scratch, a mar to the edge, nor any rust to the blade.

Re:a magnet?

[TheMidnight]

Unless a hot chick injects you in the ass with a syringe full of iron so a rather magnetic villain can escape from a plastic cell.

Re:a magnet?

[Lord Ender]

If it weren't for slashdot, I would never know amazingly pointless facts like this one. Thanks, slashdot.

Re:a magnet?

[Grishnakh]

Sorry, that's not my understanding of the metal's properties. I guess for digging around in the sand, you don't really need a fine edge, but nothing to my knowledge compares to the ability of steel (esp. high-carbon steel) to hold an edge. High-carbon steel is very brittle, which helps it to hold an extremely sharp edge; this is why Japanese samurai swords were forged to have one side harder than the other side, so the sharp side would be extremely hard, but the other side would be less hard and more strong (done by using clay on one side during quenching) so that the blade as a whole wouldn't break easily.

There's a reason no other knives are made of titanium, or anything besides steel for that matter.

Titanium is known to be a very strong metal. If you know anything about metallurgy and its terminology, strong and hard are different properties, and usually work against each other: a metal is usually strong, but not hard, or vice versa, not both. Steel can be made to be hard, but brittle, or strong (which is more flexible) but not very hard.

Anyone with a titanium ring knows that it's not a hard metal at all: it's easily scratched unless it has a protective coating (usually diamond). Sure, it might prevent a automatic pressure door on an undersea rig from locking you in, but it doesn't hold a sharp edge at all.

Re:a magnet?

[Max Threshold]

Metal detectors work by induction, so even completely non-ferrous, non-magnetic metals can be detected by them.

Re:a magnet?

[Lt.Hawkins]

Sure, it might prevent a automatic pressure door on an undersea rig from locking you in, but it doesn't hold a sharp edge at all. Nor will it stain when you drop it into a chemical toilet... Your hand may, however, be blue.

Re:a magnet?

[Gordonjcp]

amazingly pointless facts

Until the next time you try to solder something sensitive to magnetism, like a tape head. Go on, ask me how I know.

Re:a magnet?

[node159]

It probably was a composite, there is a ignorance that seems to think that titanium is a strong metal... it has a high weight to strength ratio but a poor volume to strength ratio. I've been up all night so I won't go into the details, but for example, if you wanted a broad sword made out of titanium, the blade would be about 20-30cm wide to have the same strength, and would not keep an edge, however it would be lighter.

The diving knife, if it was a good one, with a price to match, was probably a titanium alloy, with the blade edge consisting of a higher percentage of some metal with a high hardness.

Re:a magnet?

[brunson]

Actually the curve of the blade is caused by the two different alloys contracting at different rates when quenched, the clay is applied to create artistic patterns on the surface of the blade.

Re:a magnet?

[Dan Ost]

Try sticking a magnet to a stainless-steel fridge. It probably won't work because not all iron alloys are magnetic and the most popular stainless alloys used for home appliances fall into this category.

Re:a magnet?

[Anonymous Coward]

magnets work on my kitchen sink.

Re:a magnet?

[Aardpig]

I see your high-carbon steel, and raise you some tungsten carbide.

Re:a magnet?

[Brickwall]

Titanium is known to be a very strong metal. If you know anything about metallurgy and its terminology, strong and hard are different properties, and usually work against each other: a metal is usually strong, but not hard, or vice versa, not both.

Sincerely curious.. is this why titanium is so popular in golf clubs these days? Because it's light compared to steel or wood, you can presumably swing it more quickly (thus generating more kinetic energy), while because the metal is softer, presumably it deforms a bit more, and thus you get more of a "trampoline" effect. Does that sound plausible, or is it just marketing hype?

Re:a magnet?

[Anonymous Coward]

"Actually the curve of the blade is caused by the two different alloys contracting at different rates when quenched, the clay is applied to create artistic patterns on the surface of the blade."

Not true. The blade shape is purely a function of the smith's hammer. While not entirely homogeneous, the folding process used in laminate blades wouldn't give you a curve through thermal expansion.

As far as the artistic patterns (hamon) that appear on the blade after heat treating with clay, those are a byproduct of the process, not the principle effect. The primary reason for using clay is to provide a differential temper, such that the blade has a hard (but brittle) edge, and a soft (but strong) back.

Re:a magnet?

[Anonymous Coward]

"The blade shape is purely a function of the smith's hammer."

The original poster was correct. The curve is due to the different types of steel contracting at different rates.

There was a NOVA (http://www.pbs.org/wgbh/nova/samurai/) special on this not long ago.

It was fascinating to watch a straight blade go into the final quenching and come out curved.

Re:a magnet?

[pwolk]

Then again, if you know a bit more about metallurgy and its terminology, strong and hard are still different properties, yet they are usually follow the same tendency: strong materials are usually hard, and weak materials usually soft. For steel an empirical relation exists that its strength (in MPa) is approximately 3x its hardness (in HV).

Strength and toughness are the properties that usually work against each other.

Re:a magnet?

[Anonymous Coward]

"I see your high-carbon steel, and raise you some tungsten carbide."

For a personal carry knife I would suggest something with an M2 blade. They aren't stainless so you need to look after them to make sure they don't rust.

I carry one of these:

http://www.equipped.com/rsk_mk1HS.htm

Re:a magnet?

[Anonymous Coward]

Only put an apostrophe in "it's" when you are forming a contraction of "it is." This is the one and only use of "it's."

Re:a magnet?

[Grishnakh]

Yep, tungsten carbide is great for things like machine tools, saw blades, etc. But I suspect it's too hard/brittle to make a decent knife blade; it'd probably break too easily. On table saw blades, for instance, the blade is made of steel, but the edges have small carbide pieces epoxied in place to provide the actual cutting surfaces. These blades need resharpening much less than standard all-steel blades.

Re:a magnet?

[Grishnakh]

It's probably because 1) it's lighter than steel or wood, and 2) it's very strong, so it bends like a spring and stores energy, releasing it as it hits the ball. My guess, anyway, as I'm not a golfer.

However, I've noticed that carbon fiber shafts have gotten very popular for clubs these days. I think, as composite structures, these are supposed to be even lighter than titanium, while still very strong.

Perhaps a golfer can enlighten us more.

Re:a magnet?

[georgewilliamherbert]

A poor volume to strength ratio?

http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MTP642

Yield strength of 160,000 PSI and ultimate tensile strength of 170,000 PSI for that temper condition of Ti-6Al-4V, and there are better Titanium alloys out there.

Yes, some of the really high strength maraging steels get better than twice that strength. But their use is even more restricted than Titanium is, because they're exotic to work and require the aging process after fabrication to attain the high strength. Few steels with more than about 150,000 PSI strength are in wide use. A vast majority of steels used widely have ultimate tensile strength less than 100,000 PSI. The exceptions are mostly T-1 / A514 for structural steel and 4130, 4140, and 4340 for machinery and aircraft parts.

Re:a magnet?

[Anonymous Coward]

How do you know!?

Re:a magnet?

[zerkon]

My wedding band is made of tungsten carbide, I'm in the military and wanted something that would take a beating.

It's prety scratch resistant so far (only been married 2 years). They did warn me though, if my hand ever swelled up from an injury or whatever that it can't be cut off like a gold ring, they'd have to put my hand in a vise and crush the ring until it shattered.

Re:a magnet?

[Anonymous Coward]

http://home.quicknet.nl/mw/prive/luyrink/ehbotips/Het%20verwijderen%20van%20een%20ring.pdf shows how to remove a ring that cannot directly be shoved over the joints: a string is used to pull it nailwards. Some fatty liquid (milk for instance) helps as well.

Unless the finger _really_ is damaged...

Re:a magnet?

[BLKMGK]

rm, I have a several years old daily worn watch with both a titanium band and case and yet it shows almost no scratches. I believe you'll find that some rings aren't made the same - I've been told that there are issues with being able to cut them off in an emergency etc. but dunno' if that's true or not. The real aircraft grade titanium supposedly shouldn't be used for rings I was told In any case my watch isn't showing much wear at all and is light as a feather which is why I'll always want a Ti watch from now on :-)

Re:a magnet?

[GoRK]

There's a reason no other knives are made of titanium, or anything besides steel for that matter.

Except of course for all those high-end ceramic and low-end plastic composite knives that are being made these days..

Re:a magnet?

[FuzzyDaddy]

I had a friend who bought a stainless steel fridge with cosmetic damage, thinking that it would be covered with magnets holding up bits of paper.

Of course, stainless steel is non-magnetic.

Or use a cutting torch

[$RANDOMLUSER]

It heats white hot almost instantly, and when you thumb the oxygen cutting lever, you get the most amazing shower of white sparks - like fireworks - very pretty!

Re:Or use a cutting torch

[twentynine]

I thumbed your mom's oxygen level last night

He also runs periodictable.com

[Ed Pegg]

The author of this Popular Science article, Theo Gray, also recently relaunched http://www.periodictable.com/ Thousands of elemental pictures and videos are available there, all linked in with his Popular Science series.

Who chose the images of metal grinding?

[schwit1]

You've got cast iron, steel, aluminum and ... and where's the titanium? The entire article is about how to tell if the metal is titanium. They even mention to look for white sparks as the telltale sign.

DOH!

Re:Who chose the images of metal grinding?

[g0dsp33d]

While I'm guessing people with the proper light monitoring tools would still be able to tell, I am guessing the average person couldn't tell between Ti (white) and Mg (white).

Re:Who chose the images of metal grinding?

[Anonymous Coward]

The main photo at the top page of the story shows what you are looking for.

The photos in the link show other things for comparison, and not the "money shot" of the article, hence they are not on the front page.

And to the sibling respondant, you don't need a spectograph or to be an expert, the difference is quite obvious.

Also, everyone posting in this story needs to get a life and get off the internet on christmas.

Re:Who chose the images of metal grinding?

[Smidge204]

The article I clicked on - the only link in the summary as I write this - leads to a page that has both a huge photo on top showing the two side by side (titanium vs steel) but also a video where they grind various items. The difference is very noticeable.

=Smidge=

Not Just Titanium

[TheWanderingHermit]

When I tested adamantium, it gave off a shower of brilliant white sparks as well.

But they were so hot they caught my workshop on fire.

Re:Not Just Titanium

[ScrewMaster]

If you were testing Adamantium, those sparks were probably from your grinding wheel being worn down to a nub.

Re:Not Just Titanium

[kaizokuace]

well if we are going that route then I was testing to see if the armor for my robot was real Gundamanium but sadly it was not sparking brilliantly :(

Credit where credit is due...

[Anonymous Coward]

I imagine that credit card companies won't be too happy about customers grinding up their titanium credit cards.

Don't try this away from home

[dacarr]

One thing to keep in mind is that sales droids are probably not familiar with the wonderful world of minerology and/or science minded. They are sales people for a reason. They aren't the people who understand these concepts. (If anyone should understand the concept, it is you, the reader.) So as such, if you go and apply a dremel tool to, say, a platinum wedding ring you have in mind for your wife and, lo and behold, it's showering yellow sparks, the first thing through their mind is not going to be something to the effect of "aw dammit, I've been found out!", it's going to be more like "Holy f*ck! This f*cker just damaged my merchandise! POLICE!". You can't talk logic into them, and the police are more likely to side with the jeweler. Sure, you might be able to prove the jeweler wrong in a court of law and countersue for false advertising (and expose him as a fraud), but having to fart around with legal crap for months is, for one, not my idea of a good time.

This is very much a point where Hanlon's Razor can be applied.

Re:Don't try this away from home

[philwx]

Dumb sales people or not, you would be damaging their merchandise. Especially if its jewelry. They might be dumb, but you don't have the right to do kind of test until you purchase your item. So.. there must be a better way.

Mods smoke crack

[The Anarchist Avenge]

Parent is warning about fake link in the GP. How exactly is this offtopic?

Re:Mods smoke crack

[mcpkaaos]

Anonymity + mod points = control freak. Welcome to Slashdot.

Re:Mods smoke crack

[moogied]

Well you see, this is slashdot. Offtopic is actually a way to take out anger from your dog/cat/wife not putting out

Re:Mods smoke crack

[Anonymous Coward]

Your cat doesn't put out? That's, errumm... good.

Re:Mods smoke crack

[jcuervo]

Shitcock

wow

[sendorm]

there is also a method about testing if a stone is a real diamond or not. Just burn it, if it does it's indeed diamond.

I also remember the method to find out if a person was a witch or not. Just dump her in water. if she floats, she is a witch, burn her. If not what a shame, damn she is drowned anyway.

Re:wow

[Anonymous Coward]

There is also a method about testing if a stone is a real diamond or not. Just burn it, if it does it's indeed diamond.

There's long been a test for amber by poking it with a hot needle. If it smells pine-like, then it's amber. If it smells bad, it's plastic. Of course it leaves a mark.

So, how do you test fuses?

Re:wow

[techno-vampire]

You don't even need that much heat. Just warm it in your hands, and if you get a faint pine smell it's amber.

Re:wow

[Phoobarnvaz]

there is also a method about testing if a stone is a real diamond or not. Just burn it, if it does it's indeed diamond.

Once looked at a titanium wedding ring & was thinking WTF??? Since about 50% of marriages (more in the bible noose of the US) end in divorce...it's a real waste of a decent metal. Tin or copper...YES...gold or titanium...NO.

Re:wow

[jandrese]

Ah, the copper ring, perfect for people who like turning their fingers green. It also dents easily, which makes it perfect for something you're going to wear on your hand all day and bang into things. Pretty soon you'll have a moonscape replica for a ring, which is what everybody wants.

Disclosure: I actually went for the Titanium ring because I figured it would hold up under the daily stresses of my life, and I wouldn't have to clean/polish it. The only downside is that you cannot get a Titanium ring resized if your finger changes because Titanium is a real bitch to machine.

Re:wow

[Anonymous Coward]

Posted again to see if anyone wants to speak up and tell me why they think I'm off-base. Look, I can come up with AC postings much more easily than you can come up with mod points, and what I ask is so little. His sig meets every definition of spam I know of: it's unsolicited, it's commercial in nature, it's an advertisement, it does nothing to enhance the discussion, and it costs the sender nothing or next to nothing. My negative reaction to this sort of pollution is justifiable.

And what will the mods do? They'll say "oh noes! he used the word FUCK in his post, and I don't like that - time to ignore his point and abuse the mod system to enforce my tastes on others!" I feel sorry for you as a human being if this is really how you operate, doubly so since you are probably proud of this. Notice we haven't heard anything from techno-vampire on the subject? I wonder why that could be? Hmmmm... Cat got your keyboard? Too cowardly to weigh in when the facts are not on your side? I know I'm notified when someone replies to *my* account's postings. Like I said, if his spammy sig isn't "off-topic" then neither is my objection to it.

I'm glad you took the opportunity of having a sig to introduce FUCKING SPAM into every discussion in which you participate. If I need your product, don't worry, I already know about it and have compared it with others' offerings to make my own decision. If I don't know about your product, it's because I don't need it and you're a fucking spammer. If anything, if I were thinking about doing business with "1 and 1" before, I would make it a point to NEVER give them any of my money after seeing your SPAM sig. Congratulations.

Re:wow

[techno-vampire]

His sig meets every definition of spam I know of: it's unsolicited, it's commercial in nature, it's an advertisement, it does nothing to enhance the discussion, and it costs the sender nothing or next to nothing. My negative reaction to this sort of pollution is justifiable.

And, it's in my sig, not in the post itself. You not only don't have to read the sig, you can even gasp! turn off sigs in your preferences if you want. Not only that, it doesn't try to trick you into clicking on it. It's an advertisement for the web hosting company I use. Deal with it. It's not supposed to "enhance the discussion," any more than any other sig is. I'm almost certain that the only reason you keep posting this is to trick fools into wasting mod points on you instead of putting them to better use but it's not going to work, because the number of fools with mod points is too high.

Re:wow

[Anonymous Coward]

And, it's in my sig, not in the post itself. You not only don't have to read the sig, you can even gasp! turn off sigs in your preferences if you want.

Ah, and of course this leaves you blameless. Why, I forgot, it's perfectly reasonable to allow some asshat like you to destroy any utility that sigs have without saying a word, and the idea that I might prevent myself from seeing everyone else's sig just to avoid seeing yours sure must give your ego and your sense of worth a biiiiigg hard-on huh? And if you don't like the fact that drunks drive, just give up and sell all your cars. A dog might shit in your yard, damn I guess it's time to move to another neighborhood. Somewhere in your country, at least one politician or local official is dishonest, hell it's time to buy an island someplace. Fuck that. Better to give shit to spammers like you, patrol the road for drunks, shoot the dog, and vote against the politician.

Not only that, it doesn't try to trick you into clicking on it. It's an advertisement for the web hosting company I use. Deal with it.

How noble that you are such an honorable spamming sack of shit who doesn't use such filthy tricks. I guess the fact that you're not a very sophisticated spammer magically makes it something other than a nuisance. Wow and it's the web hosting company that YOU use. Why, you have financial ties to a site you are spamming, what a surprise! How kind and selfless of you to inform us of such a wonderful company. I'm sure your motives are pure.

It's not supposed to "enhance the discussion," any more than any other sig is.

The sigs are often rather witty, or amusing, or remind me of a great quote, or otherwise tell me something about the person who is posting (you are no exception, perhaps that is why your remedy is for me to disable all sigs!). However, there is no form of advertising that enhances much of anything. That's why it is that if you want to put an ad in the paper, or a commercial on TV, or on the radio, or an ad in a magazine, you *gasp, holy shit!* FUCKING PAY FOR IT. Guess what, you're getting a free ride and a free shameless plug and all because Slashdot admin look the other way (after all the Slashvertisements, I suppose they would) and the mods are too sheeplike and spineless to take a principled stand against spam which is something that practically all of them would profess to hate. Imagine, abandoning a complete idea of right-and-wrong just because the wrong is done in a more subtle fashion and you'll see how I mean "spineless". It's not like there is this high expectation of sigs that you are failing to live up to, so don't play that idiot-victim "you're asking too much" act. It's that you are going out of your way to make your sig a nuisance that you know god damned well no one comes here to see (the discussion wasn't about web hosting providers or how to enhance their profits).

I'm almost certain that the only reason you keep posting this is to trick fools into wasting mod points on you instead of putting them to better use but it's not going to work, because the number of fools with mod points is too high.

In this case I was able to accomplish two things at once. Three, if you count the fact that you didn't respond until taunted to do so by my previous post. For someone so self-assured, so confident that his sig is anything other than a nuisance and that the best way to object to it is to disable sigs entirely ... for someone so sure of himself, you sure are easy to provoke, you fucking spammer.

Re:wow

[Anonymous Coward]

Good grief, get a hold of yourself! He just mentions a hosting-company that meets his needs! In his sig!! Well, here's mine: http://www.yournamewebhosting.com/ Yep, there surely are financial ties involved because I pay them! For doing their job very good!

Re:wow

[techno-vampire]

Sigh! That's what I get for trying to reason with an idiot.

Uh oh...

[ComputerPhreak]

This story + slashdotter + eggnog + cheap "titanium" Christmas gift == fancy paperweights that Walmart won't take back because you don't have the receipt

Re:Uh oh...

[Anonymous Coward]

Walmart doesn't require a receipt.

...it was just aluminum, which doesn't burn.

[John Hasler]

Aluminum burns quite well. It's just that it is so soft that the grindstone doesn't get it hot enough to ignite.

Re:...it was just aluminum, which doesn't burn.

[sh00z]

Thanks for your comment. Coming to the discussion late, the first thing I did was search on "aluminum," to make sure that somebody had corrected the bad science. Shame on you, PopSci. If aluminum didn't burn, the Space Shuttle wouldn't exactly go, uh, anywhere.

Ow! Shit!

[schon]

Man, I just tried this with a new package of Energizer Tianium, and the spray burned a hole through my skin!

You can be sure I'll be returning these "titanium" batteries just as soon as I'm back from Emergency!

Why titanium anyway?

[Anonymous Coward]

It has good tensile strength and low weight but few applications warrant the additional expense.

Seems "titanium" has become buzzword marketing fodder for products that don't actually use any titanium. At that point they may just as well follow the cosmetics industry and start making it all up.

This comment reinforced with AC's revolutionary titulaniar carbonaficetubes for great karma!

Re:Why titanium anyway?

[YrWrstNtmr]

It has good tensile strength and low weight but few applications warrant the additional expense.

Wrong. Several I can think of. Here's a couple that I have personal experience with.
Bicycles. A Ti bike is a noticeably different ride than other materials.
Eyeglasses. Steel contains quite a bit of nickel. Many people are allergic to it, and get a rash when in constant contact with it. So, in eyeglasses, you have a choice between regular steel, Ti, or plastic. Guess which wins.

Re:Why titanium anyway?

[ScrewMaster]

Some years ago I had an expensive pair of prescription sunglasses. Went on a car trip out west with my girlfriend, and about halfway through the Badlands I couldn't find them, so I was blind for a couple hundred miles. Stopped for gas ... and found that she'd been sitting on them the whole time. Crushed them into uselessness.

So when we got back, I bought a couple pairs of glasses (one regular, one polarized) with titanium frames, or maybe it was some titanium alloy, I don't know. Unbelievably cool though. They were really too expensive, but considering that nobody (including me) was ever able to damage them they were worth every penny. I remember her accusing reply when I showed them to her: "You just bought those because I broke your other ones, didn't you!" Yep.

Re:Why titanium anyway?

[aflag]

Wrong. Several I can think of. Here's a couple that I have personal experience with. Bicycles. A Ti bike is a noticeably different ride than other materials. Eyeglasses. Steel contains quite a bit of nickel. Many people are allergic to it, and get a rash when in constant contact with it. So, in eyeglasses, you have a choice between regular steel, Ti, or plastic. Guess which wins. Plastic? I'd expect to people allergic to steel or nickel to try plastic rather than other metal.

Re:Why titanium anyway?

[Anonymous Coward]

All but one of the people I know with Ti bicycle frames have more disposable income than common sense. Like I said, the additional expense is unwarranted considering the low usage. At 3 -4 weekends a year max, they're simply poseurs. If you're serious about cycling, it's another matter entirely.

As for body piercing and eye-glasses... the nickel in stainless steel is too tightly bound to leach with perspiration. If in doubt ask for AISI 304 or 316LN and apply for copies of the mill certification. If you're wondering why 304 and not plain 316, read up on the manufacturing process (plate vs. bar). For the record I doubt spectacle frame made from 316 would trigger any allergy, sounds more like salesmen praying on consumer ignorance in order to sell a more expensive product to me.

Re:Why titanium anyway?

[YrWrstNtmr]

After having steel framed glasses for many years, and started getting a skin reaction exactly where the frames touch my skin...I asked the optometrist about it. She said "oh...you have nickel allergy. You need something else besides steel frames."

Bought the (too expensive) Ti frames, and the condition went away almost immediately. Within days. Couple years later, tried another pair of steel ones. It started coming back. All Ti from then on.

And the Ti frames are significantly stronger/more flexible.

Re:Why titanium anyway?

[YrWrstNtmr]

If you're serious about cycling, it's another matter entirely.

Exactly. I don't currently own a Ti bike, but this summer that may change. Apparently, you know too many poseurs.

the nickel in stainless steel is too tightly bound to leach with perspiration.

Stainless steel may be different, but with the more common non-stainless steel my skin tells me otherwise.

For the record I doubt spectacle frame made from 316 would trigger any allergy, sounds more like salesmen praying on consumer ignorance in order to sell a more expensive product to me.

Cross referencing all the possible different alloys with all the different frame styles is way too much work when I know the Ti does not have the same problem.

YMMV, but it works for me. Plus, the frames are actually stronger.

Re:Why titanium anyway?

[toddestan]

How is that wrong? The applications you list are areas where you would want something strong, lightweight, and people are usually willing to pay a bit more for a good bike or pair of shades, meaning cost isn't as much of an issue. Hence titanium.

I think the poster was refering to titanium graphics cards, laptops, mp3 players, speakers, credit cards, or whatever where titanium is more of a buzzword more than anything eles.

Re:Why titanium anyway?

[Anonymous Coward]

Steel contains quite a bit of nickel. Many people are allergic to it, and get a rash when in constant contact with it. So, in eyeglasses, you have a choice between regular steel, Ti, or plastic. Guess which wins.

Ummm, how about alloys of steel without nickel? There are lots of steel alloys that don't contain nickel, particularly for a low-strength application like glasses.

You see this all the time with earrings. They often are labeled hypo-allergenic which is either gold-plated or no-nickel.

Re:Why titanium anyway?

[Spirilis]

Ditto-- had some kind of "hypoallergenic" frames for a few years that were probably made from nickel or steel with a coating overtop to make it "hypoallergenic", and after the coating wore off it started giving me nasty skin problems around where the frames touch. This time around I bought titanium frames--problem went away within a month or so (it was really bad for me), and I am sticking with titanium from now on.

Re:Why titanium anyway?

[antichip]

I make Titanium rings and other non critical parts at home and very high end optic components at work. This metal takes on awsome interferance colors when heated to various points. It is a nice metal to finish.

A few simple ones

[BlueParrot]

a: Titanium is not ferromagnetic, and hence it is not attracted by magnets as strongly as iron is ( the difference in force should be orders of magnitude ).
b: Titanium's density is 4.5g/cm^3 , iron is 7.8g/cm^3
c: Titanium is corrosion resistant to dillute sulfuric and hydrochloric acid, iron is not.

Re:A few simple ones

[Anonymous Coward]

a: Titanium is not ferromagnetic So are some types of steel, so that's only good to proove that something isn't titanium.

Re:A few simple ones

[bcrowell]

Re the magnetic test, one thing to watch out for is that a lot of metal things you buy are actually alloys, and since paramagnetism and diamagnetism are generally orders of magnitude weaker than ferromagnetism, the dominant effect may be ferromagnetism from any ferromagnetic materials in the alloy. There may also be ferromagnetic parts (screws, ...) in an object that's mainly titanium. An example of this is that you can attract a piece of pencil lead detectably with a strong neodymium magnet, but I believe pure graphite is actually diamagnetic, so it would be (weakly) repelled by a magnet; the attraction is probably due to ferromagnetic or paramagnetic contaminants in the graphite. There may be a similar problem with the density test; you may have a hard time measuring the density of the titanium parts independently from the density of whatever other non-titanium parts are included or alloyed.

Re:A few simple ones

[florescent_beige]

It's hard to determine the density of something like a ring because even if you weight it you don't know its volume. But there is a way around that, weigh the item in air then in water and take the ratio of the weights. A jewelry store would be more open to that idea than coming at the thing with a power tool. Here's the arithmetic: volume of item = v density titanium = d_t density water = d_w weight in air w_a = v*d*g weight in water w_w = w_a - v*d_w*g w_w/w_a = (w_a - v*d_w*g)/w_a = 1 - d_w/d_t plugging in d_w = 1 g/cc d_t = 4.5 g/cc w_w/w_a = 1 - 1/4.5 = .78 If it's steel: w_w/w_a = 1 - 1/7.8 = .87 Most jewellers would have a setup that can weigh something immersed in water, it's how they tell themselves what the material is. If they say they don't then you are probably being had.

Re:A few simple ones

[dave1g]

...or you could have a... uh... eureka! moment and just dunk the ring in water to measure the change in volume. and then use the volume and previous mass measurement to find the density. But I suppose either method is valid, and just as difficult since they both involve a scale and water.... but one has more historical significance.

Re:A few simple ones

[florescent_beige]

It's effectively the same thing but the weight ratio is more practical. The volume of jewellery is so small that reading the change in water level in a graduated cylinder is really hard. It's generally smaller than the meniscus.

Plus most jewellers are already set up to do the water-weighing.

Re:A few simple ones

[TubeSteak]

c: Titanium is corrosion resistant to dillute sulfuric and hydrochloric acid, iron is not. Ummm.. how dilute?
I have the extra links from my Fossil Blue Titanium watch that I can test.

Interesting!

[Poromenos1]

Next up: Test if your explosives have gone bad by detonating them.

Re:Interesting!

[Kazymyr]

If you know of a more reliable way, I'd like to hear about it. No, seriously.

Re:Interesting!

[BlueParrot]

If you know of a more reliable way, I'd like to hear about it. No, seriously.

Physics to the rescue:
http://en.wikipedia.org/wiki/Elitzur-Vaidman_bomb-tester

Re:Interesting!

[Anonymous Coward]

or Psychics to the rescue:
http://en.wikipedia.org/wiki/Wave_function_collapse

if you're not into this spooky quantum physic :)

Re:Interesting!

[Anonymous Coward]

How does one make a single-photon detector that doesn't absorb a photon if the bomb is a dud?

Re:Interesting!

[c6gunner]

You may have just discovered the REAL purpose behind the invasion of Iraq....

Re:Interesting!

[Kazymyr]

I said "reliable". To quote from the article:
On average, this will identify all of the dud bombs, explode half of the usable bombs, and identify half of the usable bombs without detonating them.

Of the non-exploded bombs, you won't be sure which one is a dud and which not.

Re:Interesting!

[Poromenos1]

Most people would put "not destroying all usable bombs while testing" above "making sure it works", but not you! You work for the government, don't you!

Re:Interesting!

[Kazymyr]

You got it almost right.

The government works for me! Muhahahahahaaaaaa.....

Re:Interesting!

[Anonymous Coward]

On average, this will identify all of the dud bombs, explode half of the usable bombs, and identify half of the usable bombs without detonating them.

Of the non-exploded bombs, you won't be sure which one is a dud and which not.

So by your own definition, if it neither explodes nor is identified as a dud, then you know it's usable. Where's the "won't be sure" part come in? Reading comprehension is important, you dumbass.

Re:Interesting!

[Kazymyr]

Dear AC,

You could try reading the article. You would know then that the procedure leaves you with a category of "possibly dud, and possibly good" bombs. And you have no way of distinguishing them.

Yours truly,

Dumbass.

Re:Interesting!

[Anonymous Coward]

The article also points out that you could test your bombs from that category again, gradually improving your results. Furthermore, "In 1996, Kwiat et al. devised a method, using a sequence of polarizing devices, that efficiently increases the yield rate to a level arbitrarily close to one." So what's the problem here, dumbass?

Re:Interesting!

[foreverdisillusioned]

Wrong. Read the article again. If you get a hit at detector C, the bomb is usable, yet it does not explode (in our universe. According to the many-worlds interpretation of what's happening here, it DOES explode in an alternate universe, and we're basically detecting the results of that explosion. Freaky shit, I know.)

Laser?

[Anonymous Coward]

What are they teaching kids in school these days?

GRIND THIS!

[denzacar]

Apparently, Google has "interesting" sense of humor regarding titanium products.

Re:GRIND THIS!

[zackeller]

Well it does encourage maximum hardness.

Re:GRIND THIS!

[denzacar]

Yeah, but in the light of recent developments - it appears to be prone to cracks and breaches.

Tip

[monoqlith]

Don't try this with your Powerbook G4 Titanium.

Re:Tip

[Anonymous Coward]

Why not ? I've seen some cool effects done on PowerBook G4's...

Titanium: not recommended for rings

[steveha]

I read a story about a couple who loved bicycling (and loved their titanium bicycle frames). They decided to have rings made from titanium.

One day the guy had some kind of accident, and his ring finger was mashed; it swelled up badly. They took him to the emergency room. In the ER, someone got out the cutters to cut the ring off the swollen finger. Whoops, titanium. The cutters (probably simple diagonal cutters) had no problem with the usual soft gold rings, but titanium was too hard! They wound up getting a Dremel tool or the equivalent and cutting the titanium ring off (very carefully, I imagine).

The moral of the story: if you get a titanium ring made, maybe you should wear it like a necklace.

P.S. Merry Christmas everyone.

steveha

Re:Titanium: not recommended for rings

[Anonymous Coward]

I that likely imaginary anecdote, the force that was required to crush his titanium ring would likely have nearly destroyed his ring finger with or without the ring. Maybe the ring saved his finger? See the myths about steel toed boots versus composite for another instance (with the exception of electical conduction). Gold is an extremely soft metal, it's not surprising went it bends (try with a gold ring in your hands, it will deform easily; getting it back to perfectly round might be difficult though).

Re:Titanium: not recommended for rings

[Anonymous Coward]

I suppose the anecdote could be imaginary, but I did read it in a bicycling magazine. I didn't make it up.

And I'm puzzled by your comments about the ring saving his finger. My understanding is that his finger got mashed, not that the ring got mashed hard enough to deform it. So he had a finger swelling up, and a non-deformed ring at the base of the finger.

steveha

Re:Titanium: not recommended for rings

[Nexzus]

About 18 years ago, I was on an underwater oil-drilling rig, when the mission we were "tasked" to perform by the navy went horribly wrong, and the rig started taking on water. I was running frantically running through cold freezing water towards a closing hydraulic door. I didn't make it in time, but I stuck my hand in the opening, and the door was stopped by my titanium wedding band. A colleague had found me, cut the hydraulic power to the door, and saved me. Earlier I had almost flushed it down the toilet. Good thing I didn't.

Couple hours later I met some aliens.

(Yeah, I know, but it sounds better in 1st person.)

Re:Titanium: not recommended for rings

[1729]

Actually, titanium rings can be cut off fairly easily, at least according to the guy who made my wedding band:

http://boonerings.com/faq.htm#4

Tungsten carbide rings are difficult to cut, but they can safely be cracked with vise grips:

http://www.trewtungsten.com/remove.php

Re:Titanium: not recommended for rings

[Anonymous Coward]

Put the ring in a vice and slowly compress it until it cracks, that's the recommended way to get a tungsten ring off anyways.

Re:Titanium: not recommended for rings

[Henry V .009]

I must be missing the reference here...

Re:Titanium: not recommended for rings

[ghideon]

Ed Harris' character from the Abyss.
http://imdb.com/title/tt0096754/

Re:Titanium: not recommended for rings

[dbIII]

Strong than gold yes. Stonger than stainless steel no. There's a lot of myths about this stuff and people who mix up strength to weight ratios spread a few.

Re:Titanium: not recommended for rings

[dbIII]

I must be missing the reference here...

An abysmal movie (The Abyss) that actually got some physics right but certainly not that bit.

Re:Titanium: not recommended for rings

[ColdWetDog]

Put the ring in a vice and slowly compress it until it cracks, that's the recommended way to get a tungsten ring off anyways.

Oh yeah, that ought to be a comfort to a patient in the ER:

"Ah yes, we need to take that titanium ring off, here - put your finger in this vise. This will take just one jiffy."

I think I will stick to the ring cutter.

Re:Titanium: not recommended for rings

[snoopyjd]

I worked as an EMT for a while. I was doing a ride along on an ambulance and responded to a call at a basketball court. Some guy went to dunk and got his ring caught on the hoop. Almost all the tissue on his finger was ripped off.

The moral of the story - cut your ring most of the way through. If it gets caught it will hopefully break before it removes your finger.

Re:Titanium: not recommended for rings

[eli pabst]

Yeah, I remember hearing the same thing when I was shopping for wedding rings and came across some made of tungsten carbide. They are supposedly 4x harder than titanium. Interestingly, I just came across this about tungsten while writing this post, so I assume they can cut titanium as well:

"In the event of an emergency, a ring can be removed by a medical professional."

Re:Titanium: not recommended for rings

[rizole]

Surely the moral of the story should be something like: Whatever precious metal you prefer your jewellery made from, don't get your fingers mashed up.

Yes but

[Anonymous Coward]

Will it blend?

So I have to grind it great!

[dindi]

Probably it does not matter with my titanium dive knife if I have to grind into it a bit, I could actually sharpen it as well (not that it is not razor sharp already)m but the question is if you want to really grind into that titanium fancy case, that pen, or other "cool" device you just got.

I was honestly hoping for a less destructive testing method. On the other hand just for curiosity, I really would not buy titanium for the "bling" factor, only for its strength and weight. And where you need those, you will know just by looking and weighing if it is titanium or not.

Or just buy decent brands maybe?

Safety first?

[ELProphet]

He's not wearing any gloves! The safe Boy Scout in me is not impressed!

Re:Safety first?

[smidget2k4]

Gloves + rotating grinder = BAD. You don't want a glove to get caught in that, your hand goes with it. Better to be burned by some sparks than to lose a few fingers (at best).

Re:Safety first?

[Anonymous Coward]

No doubt...

Saw a man lose 2 fingers and associated tendons while I was at work at Lockheed a few years ago....

Pretty messy sight. Gloves pulled right through and shattered the saftey guard....Next were the fingers and tendons.

They can be cut off.

[raygundan]

I know an ER doc who thought the same thing, until somebody came into her ER with one, and it was as trivial to cut off as anything else. Even if they lack a proper cutting tool, you can just squeeze it until it shatters. Titanium is strong, but it's not like a ring made of the stuff is somehow immune to being cut or broken. Hospitals are full of interesting tools, and it sounds like even in your story, they improvised fairly well.

Give the OP some credit here

[raygundan]

He didn't say the *ring* was crushed, he said the *finger* was crushed. The ring doesn't have to deform at all for the finger to be injured enough to swell up larger than the ring, which necessitates cutting the ring off. But titanium shouldn't present a problem to the emergency department. Even one without a special tool for titanium rings will likely improvise just fine, as in the original poster's example. There's no shortage of interesting tools in a hospital, and doctors are reasonably smart people.

Pile of Dust

[Nom du Keyboard]

Hello Customer Service. This pile of titanium dust is what's left of your expensive titanium product after I tested it to ensure that you weren't lying. I expect it to be replaced by a brand new product immediately, now that I know you're honest. Thank you very much!

Jiffy pop

[morcheeba]

We were ready to pop some Jiffy Pop at a campfire, when then noticed it had a warning "do not use in campfires." We tried it anyway... the aluminum foil pan burned in to nothing before the popcorn popped, so we were left with just the steel handle.

Direct comparison is enlightening

[NtroP]

I have a large Seiko titanium wrist watch that I invested in a few years ago. To this day it's interesting to hand it to someone and see the look on their face when they take it. It's rather plain-looking and "feature-free" for something so frickin' expensive, but when they feel how light it is, they can hardly believe it. I must have very acidic sweat because I rot leather and canvas watch bands like crazy and metal bands actually corrode away on me. This is the first watch I've owned that has literally shown no wear at all since I bought it. Normally by now, I'd have gone through three or four watches.

No. I will not be grinding into it.

Re:Direct comparison is enlightening

[Antique Geekmeister]

So to test all these rings and things to non-destructively see if they're titanium, we should just give them to you to wear?

Re:Direct comparison is enlightening

[Jaime2]

I have two Seiko titanium watches and a titanium wedding band. My experience is similar to yours. Although I didn't see them as quite as expensive as you do. My ring is cheaper than a gold ring of equivalent design, and I got the second watch for a little over $100 to use as a backup while the first is in the shop (second time unfortunately, but Seiko has been really good with me about fixing it for little or no charge and it's 10 years old).

Re:Direct comparison is enlightening

[dbIII]

You can weigh the stuff and then find out how much water it displaces to work out the density. Running naked through a town in Greece is optional.

Re:Direct comparison is enlightening

[Antique Geekmeister]

Of course, you do have to drill holes or melt it down to check if it's hollow. But if you melt it, you can douse it in the water and save a step!

The power to the door was pneumatic though

[Dr_Barnowl]

.. not hydraulic

Works like a charm

[aflag]

I tried the method with my tennis racket. Indeed, it *was* titanium.

Marketing BS

[Anonymous Coward]

All the titanium hype is just pure marketing BS anyway.

They're capitalizing on the idea that titanium is high-tech and expensive. Which it is. But that's relative steel
and aluminum. Aluminum costs about $2,500 a (metric) ton. Titanium, on the order of $50,000/ton. Contrast that to gold, which'll cost you around $25,000,000/ton.

So titanium jewellery? I'll pass. In fact, I read an article where a metals wholesaler said that he didn't even bother to charge for the small amounts used for designer jewellery.

It's all just a marketing stunt. Titanium isn't actually better than the metal it's replacing a lot of the time. To take an example, I saw an expensive titanium camp stove (as opposed to aluminium). The stupidity of that, besides being heavier, is that titanium sucks as a heat conductor, in particular in comparison to aluminum (what's your CPU heatsink made of?)

Instead of asking themselves "Is it really titanium?", people need to ask "Why does it need to be titanium?"

Re:Marketing BS

[Anonymous Coward]

uh, copper? it's got a plastic fan on it, too.

Re:Marketing BS

[Anonymous Coward]

It's interesting that you're selecting suitable metals for jewellery simply on the basis of which is more expensive - assuming that more expensive is better.

Personally, I have no problem with people choosing jewellery for other factors (durability, corrosion resistance, even *gasp* appearance). Why would you want to use gold, just because there isn't very much of it? Conspicuous consumption is a pointless waste of society's resources.

Re:Marketing BS

[Anonymous Coward]

All the titanium hype is just pure marketing BS anyway.

Not entirely:
http://www.guggenheim-bilbao.es/img/all/el_museo/foto_postal_08.jpg
http://www.guggenheim-bilbao.es/secciones/el_museo/el_edificio.php?idioma=en
http://www.stainless-steel-world.net/titanium/ShowPage.aspx?pageID=206
It is very pretty and durable.

Oh jebus, I hope I haven't given any vandals a bright idea... one hot torch (~2200F) could make a real light show of that place (for a few seconds). I wonder if they have appropriate security and preventative measures in place.

Anyway, the point was, titanium is a beautiful metal in such large quantities, it has unique optical characteristics.

Re:Marketing BS

[Ant P.]

(what's your CPU heatsink made of?) Copper. Feels like it weighs a ton too, despite being one-third the size of the stock aluminium one. It conducts heat good enough that on cold days I can safely yank the fan and have an almost silent system. Not bad considering it's a P4.

Re:Marketing BS

[athakur999]

Titanium is one of the few metals I can wear for a significant amount of time without my skin breaking out. The only others I know is pure gold. Everything else I've tried, even those labeled as "hypoallergenic" cause me to begin to break out after a few days.

Since a pure gold jewelery would be both expensive and scratch up very easily, that leaves titanium for my wedding band and my watch. I wish I could find something a bit heavier though. Titanium jewelery is not very substantial feeling due to its light weight.

I tried a tungsten carbide ring but it caused me to break out as well. Now the quest for another "alternative" metal continues anew :)

Re:Marketing BS

[TheThiefMaster]

I use an Arctic Cooling "Freezer" cooler, which is a big copper heatpipe cooler, on an AMD X2 cpu. The motherboard is set to automatically adjust the speed of the cpu fan. I had to turn off the motherboard's "slow/stopped cpu fan" warning, because the cpu ran so cool that the motherboard intentionally ran the fan below the lowest warning level.

I could probably run this without the cpu fan even on a hot day.

Re:Marketing BS

[notnAP]

Indeed, many people have similar problems, myself included. For this reason, I don't wear any jewelry, and even my gold wedding band (not 24k) caused occasional problems. (Divorced now, so problem resolved.)

More significantly, I do need to wear glasses, and contacts don't agree with me. As was mentioned in another comment, many people have bad reactions to even hypoallergenic frames. After going a month or two constantly coating my frames with clear nail polish to avoid the blistering rash I got everywhere metal touched, I spent the money for a titanium frame. No more problems.

For many, it isn't a matter of "bling," as the GP mentioned.

Re:Marketing BS

[mpaulsen]

To take an example, I saw an expensive titanium camp stove (as opposed to aluminium). The stupidity of that, besides being heavier, is that titanium sucks as a heat conductor

Why would you want it to be a good heat conductor? You're not trying to heat the cookware via conduction.

Re:Marketing BS

[lhaeh]

I think you are missing the point on its cost: Titanium isn't expensive to buy, but it is very expensive to machine.

Re:Marketing BS

[ambrosen]

To spread the heat from the flame as evenly as possible, avoiding hot spots, thus helping to prevent burning.

Re:Marketing BS

[demi]

The Coward above hasn't really thought this through. First off, the conduction he's talking about is of interest on the pan, not the stove--the pot supports on a backpacking stove (the kind that get made out of titanium) are there to do just that: support the pot. Even on real gourmet gas cooktops the flame contacts the pan, not some kind of conduction plate. With titanium, you can make a really light stove because the stove supports and other pieces can be thin but won't bend, like they would with aluminum. It's strength per ounce that is the primary consideration.

Now, cooksets (the pan) also come in titanium, and it's for the same reason. "Spreading the heat out" sounds like a good idea, and it is a good idea in a gourmet kitchen, but it's a secondary consideration to weight, on the trail. Backpackers don't carry enameled cast iron pots or copper-bottomed aluminum pans on a trip, because fancy heat conduction is of minor importance compared to lugging it around. Because aluminum is weak, you need to use more of it in a cookset. Compare, for example, a typical three-piece cookset: stainless weighs in at well over a pound, aluminum at 14 ounces and titanium at half that, 7 ounces.

Obviously, the titanium products are aimed at people for whom weight is a primary consideration, but really, it only takes one backpacking trip to appreciate that that's essentially everyone. A 7-ounce weight savings may not seem like a lot, but repeat that over all your equipment and you might be saving several pounds. At about a $15 price difference for the titanium set over the aluminum set, given the longer lifetime, that can definitely be worth it.

Re:Marketing BS

[BlueParrot]

I tried a tungsten carbide ring but it caused me to break out as well. Now the quest for another "alternative" metal continues anew :)

I'm not a chemist, but I imagine it should be plausible to coat a tungsten ring in a layer of titanium using electroplating. Dnno if it would be pure enough for your needs thou.

Real men (and women)...

[Anonymous Coward]

...want only the real Adamatium.

Wow...weeks behind...(dot)...com...

[DrStoooopid]

Popular Science beat the number 1 source for science news and information? You guys are slipping at /.

Besides, everyone knows Titanium gives off white sparks. Did we not pay attention in Science class? Hell Popular Science even did an article about Titanium specifically. So maybe we should change that title from weeksbehind(dot)com to decadesbehind(dot)com.

Corporations and Marketing Departments are always going to mis-represent the facts....welcome to the 21st century. That's just a given.

What kind of pansy want's Titanium?

[Colin Smith]

Titanium is a woman's metal. Real men use Tungsten.

Re:What kind of pansy want's Titanium?

[twifosp]

Pfft. Real men use depleted Uranium. Me? I go one step even further. My wedding band is made from Plutonium.

Re:What kind of pansy want's Titanium?

[Anonymous Coward]

I imagine the same kind of pansy who insists on using apostrophes only when necessary. Bunch of loser's.

Re:What kind of pansy want's Titanium?

[Khyber]

http://trewtungsten.com/

Damn right real men use Tungsten.

Re:What kind of pansy want's Titanium?

[atamido]

A Tungsten/Platinum ring? I hope you're never in an emergency where the the ring needs to be removed and you have have one that you can neither crush nor cut. Sounds dangerous.

Re:What kind of pansy want's Titanium?

[Gkyluig]

Yep, platinum is for girls--they use Tungsten to cut it. But no worries, atamido: http://trewtungsten.com/remove.php

Re:What kind of pansy want's Titanium?

[Colin Smith]

Sounds dangerous. Yeah. HIGHLY risky.

Testing is wayuch easier

[trib3003]

As we all learned from this Documentary called "The Terminator" (released lately in 1080p):
"Its framework is a hyper alloy titanium combat chasis" (wh00!)

So, whenever the time is right and i need to know if the object of my interest is titanium or not: i'll just shoot it!
If it's still alive: it is (ass seen in above mentioned docu) titanium most likely ... if it's dead: No way it's sweet titanium!

These science thingies are so ez sometimes once u only start to use your brain, i just realize!

Have some eggnog too,
trib

It reminded me of something that I had happen

[edwardpickman]

We were building a rig for a show and there were a lot of surplus aitcraft parts around. I found a large bracket that was perfect but it needed an extra hole drilled in it. The piece was light enough I assumed it was aluminum. I was using a hardened drill bit that should have cut through stainless. After five minutes I checked it and I barely scratched the surface. Aircraft Aluminum can be fairly hard but it seemed rediculous so I tried again but still nothing. I flipped over the part and there stamped/cast on the otherside was Titanium. Needless to say I gave up. All I managed to do was kill a good drill bit. If it seems really light for it's size and can't easily be scratched there's a good chance it's Titanium.

Re:It reminded me of something that I had happen

[greyhueofdoubt]

You were either using a really dull bit, or you were using a bit that was too large and needed to be pilot drilled.

I work with titanium all the time, and we use the same cobalt steel bits for Ti work that we use for anything else. It is rough on end mills, but at that point you should be using specialized coolants and cutting speeds.

The best way to test for Ti? Heft. The stuff can look like steel to a layperson (I personally think it's easy to tell Ti vs CRES vs Fe) but the feel of it is very different. If you pick up a metal piece that feels like it should be hollow because it's so light, it might be titanium. Or it could be hollow, I suppose.

If the piece is large enough, you can ring it with another piece of metal and listen for the sustain. Titanium parts, e.g., guide vanes, will ring considerably longer and at a higher pitch than softer, heavier metals (steel) or softer, lighter metals (aluminum, except the harder allows like 7075).

Or send the parts to me, I'll take a look. If they're fakes, I'll just toss them on the scrap heap. Promise.

-b

Re:It reminded me of something that I had happen

[Anonymous Coward]

Titanium's not a hard metal. It's strong and it's tough, which are mechanical properties independent of hardness (hardness governs the scratch test).

You should be able to scratch titanium with any moderately hardened tool steel. You won't necessarily be able to machine it. Titanium is a tough metal (a simplification is that toughness is a measure of the energy consumed to break it, while strength is a measure of the force required to break it) has a tendency to get hot and weld itself to cutting tools. Machinists who work with it regularly can tell you that you need to run at very specific feeds and speeds with tools that have certain rake angles and plenty of coolant or cutting fluid. What probably happened to you is that the flutes ended up coated with titanium making them effectively dull and unable to cut.

Obviously the different grades have different properties. Any of the commercially pure grades (1-4) will be pretty soft. I have two titanium rings I made out of CP2 with a cordless drill, a hacksaw, and a set of files. Took forever, but it worked. I made a third ring from the leftover scrap using a lathe and carbide tools, and it cut like butter. The alloyed grades, like TiAlVa or TiAlNb, can get considerably harder, especially from heat treating.

Also, titanium, when polished, has a unique color that doesn't look anything like aluminum or steel.

So what's next? platinum?

[sectionboy]

someone please tell me how to tell if there's real platinum in my Capital One® platinum Card, I always want to know.

Re:So what's next? platinum?

[stile99]

Send it to me. I'll be glad to check it out for you.

so this explains the "titanium" watch....

[InfoHighwayRoadkill]

That I got real cheap that was covered in scratches within about a year and then the strap looked like it was corroding... I took it to a jewelers to get a new strap and they said "its not worth it".

Re:so this explains the "titanium" watch....

[cunina]

Actually, titanium scratches pretty easily. Like a steroid abuser in bed, it's strong, but it's not hard.

Archimedes principle?

[Ernesto Alvarez]

If the object is solid, why not use the archimedes principle?
It worked for gold, why not for titanium?

Question about my Titanium Ellis Buttress Plate

[dafing]

made my Downs Surgical Limited England, it came from a hospital (along with a bunch of tools from the morgue) but I doubt they put T4 Titanium into dead bodies? It was in packaging, just opened it now so I could grind it (JOKING!) and I cant seem to find any info about what a "Ellis Buttress Plate" does inside the body. Maybe I dont want to know... Its shaped like a T, with places for two recessed screws. The end of it the horizontal part is smooth, the end of the other bit is rounded around where the screw would be.

Can anybody help me?

Re:Question about my Titanium Ellis Buttress Plate

[AgentPaper]

It's a bone fixation plate for use in hand and wrist fractures - e.g. a Colles' or Smith's fracture, or some other fracture of the distal radius (wrist end of the outermost bone in your forearm). How you got hold of one, though, I'm not sure I want to know. They're not exactly cheap, and hospitals track their stock of orthopedic implantable items extremely closely, both due to their expense and due to the fact that they frequently have to be custom ordered.

Orthopedic implants are almost exclusively titanium or 316L alloy, with a few items (articulating surface liners, implant shaft sleeves, etc) made of PTFE or various ceramics. We prefer to use titanium or titanium/ceramic devices in younger patients and active older adults, as they have a much longer working lifespan and they'll take a lot more damage before they require replacement.

Re:Question about my Titanium Ellis Buttress Plate

[dafing]

Thank you very much friend!

I take it you work with these or similar :) I'm very glad you took the time to explain what they are used for, thank you very much, from the bottom of my heart.

It just came in with the tools, I knew it must be something special so I got it for myself, I am a little curious now for what they would be worth haha, I paid NZ$20 which would be like US$15 I would guess. Would you be so kind to tell me how much it could possibly be worth, you know, just so I could have an idea, its ok if you dont say, just would be something interesting to know. I have one question for you, just something simple I bet, how does it attach? I can see it has screw holes, but the other end is like a smooth blade really, not sharp enough to cut into bone etc, and it doesnt have any way for a screw to be put through it etc short of drilling a hole for that in it.

Its interesting what came with it too in its little sealed bag, just some basic instructions the surgeons would know, its not sterile, its T4 Ti etc etc. It mentions not to reuse them, I can imagine the trouble a broken one could cause. I did know about using ceramic parts, read about Hip Replacement on Wikipedia, they have a very cool Titanium part in the hip joint I'd rather like to have one but that could be a bit...icky for lack of a more masculine word :)

Thank you very much for your help, I was genuinely at a loss to find out, I actually emailed the company that makes them in England and they didnt bother to respond. Thank you for taking the time.

Try licking it?

[foxalopex]

Last I recall Titanium isn't very reactive so when you lick it, it shouldn't taste like metal.

So...

[cyberjock1980]

Does Unobtanium burn bright white too? Anyone got a sample and can confirm?

If it's important you can tell

[syousef]

If it's a decorative piece of jewelry or similar the properties won't matter too much at least in the short term. The jewelry wont magically change into something unwearable. The decorations won't suddenly turn to dust etc. If you're buying the metal for it's value in a piece of art, you're an idiot and have been ripped off whether or not it's titanium.

If it actually matters whether you're using titanium, you'll know about it. Not titanium in the skin of that shiny new SR-71. Well your plane will melt won't it.

Now what are people being taught in science class exactly? Yes testing the hardness of a metal is one (destructive) way to test if it's the real deal. Corrosion and reactivity are another way. But has no one ever heard of measuring the density and electrical conductivity of a metal? Honestly what do you people learn in science classes?

Theodore Gray is clueless.

[SvnLyrBrto]

Titanium and steel may very well spark in the manner he describes. But this little gem, so far as I'm concerned, renders everything he says suspect:

it was just aluminum, which doesn't burn.

Aluminum most certianly *DOES* burn. Though fairly difficult to ignite, aluminum burns ferociously and spectacularly and is notoriously difficult to extinguish, as the crew of the HMS Sheffield learned much to their dismay. The fuel of the Space Shuttle's solid rocket boosters is aluminum. And aluminum is the fuel component of thermite.

I think that the "scientific" opinion of anyone so clueless as to try to claim that aluminum won't burn should be discarded with the lowest grain of salt

cya
john

Re:Theodore Gray is clueless.

[c6gunner]

I'm sure he meant to say "it was just aluminum, which doesn't burn while being ground".

Let's not assume stupidity where a simple misunderstanding is possible.

Re:Theodore Gray is clueless.

[bwcbwc]

Calling Gray clueless because he doesn't add qualifiers like "when ground at room temperature" in a general public magazine is a false argument, because under the STP conditions that are in the normal realm of his readers' experience, his statement is true.

And your own examples are even more bogus:

The sinking of the Sheffield is sometimes blamed on a superstructure made wholly or partially from aluminium, the melting point and ignition temperature of which are significantly lower than those of steel. However, this is incorrect as the Sheffield's superstructure was made entirely of steel.[6] The confusion is related to the US and British Navies abandoning aluminium after several fires in the 1970s involving ships that had aluminium superstructures.

Yes, aluminum has a lower melting and ignition temperature than steel, but do you have any citations of disasters caused by Aluminum ignition? The cases I've found where Aluminum contributed to fire-related disasters reflect the fact that Aluminum structural features melted (about 660C) and caused structural failure, not because the metal started burning. On the other hand, Magnesium is infamous for the Apollo 1 ground fire and requires specialized equipment to extinguish:

Water should not be used to extinguish magnesium fires, because it can produce hydrogen which will feed the fire, according to the reaction: Mg (s) + 2 H2O (g) --> Mg(OH)2 (s) + H2 (g) or in words: Magnesium (solid) + steam --> Magnesium hydroxide (solid) + Hydrogen (gas) Carbon dioxide fire extinguishers should not be used either, because magnesium can burn in carbon dioxide (forming magnesium oxide, MgO, and carbon).

Not to mention that there's a big difference between metallic aluminum in a person's home and the mixture of aluminum with oxidizing and other compounds used in thermite and rocket fuel. Perhaps the fires in the Sheffield were so difficult to extinguish because of the rocket fuel, rather than aluminum aboard the ship? Saying aluminum is flammable because thermite is explosive and solid rocket fuel is hard to extinguish at least as sloppy as Gray's work, if not more-so.

Re:Theodore Gray is clueless.

[bill_mcgonigle]

Let's not assume stupidity where a simple misunderstanding is possible.

Aww, but then how can we fly off the handle, proving our superior intellect while simultaneously demonstrating how to be righteous asshat?

Wait, this isn't therapy?

Hello!

[CODiNE]

Powerbook owners where are you??

Famous last words...

[Anonymous Coward]

Hmmmm...I wonder if this works with magnesium?

Re:Famous last words...

[notnAP]

You posted anonymously, but you do realize your anonymity will be gone the moment video of your death hits YouTube, don't you?

Re:Famous last words...

[argent]

Bulk magnesium doesn't burn very well, and it's pretty soft, so you shouldn't get sparks.

The resulting ground magnesium dust, though, burns quite well indeed. Do be careful with it. For example, don't grind tutanium immediately after grinding magnesium. :)

serious uses

[Anonymous Coward]

Light weight and greater strength are basically the holy grail for things like engine parts. Of course counterfit titanium rocker arms, con-rods, etc. would result in some blown engines, so that sort of thing isn't going to fly. The manufacturers who are going to be able to pass off fake goods and get away with it are selling to people who don't have a specific need for it anyway.

Somebody around here smokes crack

[MachDelta]

Well you see, this is slashdot. Offtopic is actually a way to take out anger from your dog/cat/wife not putting out

I don't know what's more frightening. The fact that "dog" and "cat" are listed before wife, or the fact that some genius with mod points actually dropped a "+1 Insightful" on the parent post...

Re:Somebody around here smokes crack

[moogied]

I suppose the far most.. fuck you. lol :P

No dremel?

[ed1park]

How bout a blow torch, chlorine gas or liquid oxygen? :)

Even bulk titanium metal is susceptible to fire, when it is heated to its melting point. A number of titanium fires occur during breaking down devices containing titanium parts with cutting torches.

When used in the production or handling of chlorine, care must be taken to use titanium only in locations where it will not be exposed to dry chlorine gas which can result in a titanium/chlorine fire. Care must be taken even when titanium is used in wet chlorine due to possible unexpected drying brought about by extreme weather conditions.

Titanium can catch fire when a fresh, non-oxidized surface gets in contact with liquid oxygen. Such surfaces can appear when the oxidized surface is struck with a hard object, or when a mechanical strain causes the emergence of a crack. This poses the possible limitation for its use in liquid oxygen systems, such as those found in the aerospace industry.

http://en.wikipedia.org/wiki/Titanium

Call me paranoid, but I think I'll stick to gold if I ever wear jewelry. But interesting to know if you're ever in a McGuyver type situation. :)

Re:No dremel?

[owndao]

To the best of my knowledge 3-D Neutron Beam Analysis is the best non-destructive test available. It will not be affected by layers, etc. See http://focus.aps.org/story/v17/st20/ for a detailed explanation. Last I heard this method was going to be used at border crossings and on shipping containers to examine contents without opening any containers.

Site idea...

[PhotoGuy]

WillItGrind.com... Anyone got a spare iPhone to donate?

Or indeed cars.

[ambrosen]

It's the brand name for Ford's higher spec models here in the UK.

Spark test

[cephus440]

While the poster's intentions are great, the description doesn't help much at all.

To do an actual spark test, you would take a piece of known metal, spark it (with the hand grinder as described in the post) and spark the material in question. Some tool steels (like M42) give off a red spark.

Other characteristics of Ti:

Titanium is not magnetic!
Titanium will explode in powder form (seriously, I was machining Ti for a couple days straight and a spark lite my pile of chips on fire!)
Titanium is the 9th most abundant material on Earth (it's in everything, but rarely found by itself)
Most Ti deposits (with less impurities) are found in good ol' Russia

Sure the Russian way

[tbcpp]

There's always the Russian way, 'cause you know in that country the titanium holds the grinding wheel to you! Although you may find the US/EU way less painful.

X-Ray spectroscopy

[Goldsmith]

First, get out your electron microscope (what, you don't have one?), and get your pumps ready to go. Then make sure your x-ray spectroscopy system is installed, and that your photodetector has been cooled properly. Get out a piece of silicon, or pure copper or something like that and calibrate your detector and software. Then, you can load in your "titanium" item and analyze it. Not only will you find out just how much titanium is in there, but if you get good with the system, you can find out exactly what kinds of impurities you have around, without grinding bits of it off. ... at least, that's what I did...

AOL CDs

[ThatSandersKid]

I'm sure I've got one that says "AOL 6.0 Titanium" somewhere around here.

Resistivity

[JAGrady]

Assuming that the object in question is reasonably homogeneous, you could always try to determine the resistivity of the metal. That of titanium is 0.420 m. This being Slashdot, I assume you all have a four probe multimeter, right?

Samurai Sword

[fahrbot-bot]

this is why Japanese samurai swords were forged to have one side harder than the other side, so the sharp side would be extremely hard, but the other side would be less hard and more strong

Actually, the inner core is made of the softer steel, which is wrapped with the higher-carbon steel that forms the cutting edge. The (straight) sword is quenched and the softer steel contracts more (because of less carbon) than the outer high-carbon steel causing the sword to curve. The clay is used to create and preserve decorations on the blade face. High-quality swords can run over $100k.

Thank you PBS and NOVA, Secrets of the Samurai Sword, which shows the manual process from raw materials to finished sword.

Re:Samurai Sword

[MadUndergrad]

The clay also allows differential heat treating. Depending on the design of the sword, it may still have high-carbon steel toward the back, so the clay allows that to cool more slowly than the cutting edge when quenching so that it's tougher than it otherwise would be. The clay does also, of course, make a pretty temper line, but that's not its sole purpose.

Re:Samurai Sword

[fahrbot-bot]

Cool! I either missed that on the show, or it wasn't fully explained, but it makes sense. Thanks! That was one of the best hours on TV in recent memory...

Jaw Plates

[skeeto]

I will have titanium plates surgically placed in my jaw next week. I saw the headline and thought, "Heh, I could cehck if it really is titanium!" Then I got here,

Hold any genuine titanium metal object to a grinding wheel

I think I will take the doctor's word on it instead.