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Electrolytic Etching, For What A Dremel Can't Do
Dustin writes "A lot of people modify computer cases, often requiring them to cut intricate custom designs in
sheet metal. For most, there is the Dremel tool. But
sometimes, that just isn't good enough. Possibly due to an insanely complex design, or
unsteady hands, a Dremel just might not cut it (pun honestly wasn't intended). JimBob, a member at OverhauledPC.com, has a much better way. Using
readily available salt water and electricity, his technique is much easier than trying
to cut patterns with a rotary tool."
I preloaded this into the Coral Cache, just in case it gets slashdotted.
Here's the Cache Link if it's needed.
Or maybe someone used one in the server network cable... no comments and down.
Using readily available salt water and electricity, his technique is much easier than trying to cut patterns with a rotary tool.
The site is down. Therefore I will assume that he poured water over the case and shocked the shit out of it.
You could get some interesting burn patterns that way. You might even match your case.
The coolest voice ever.
any of the paying Slashdotters wanna grace us with the text?
;)
I promise you'll get lots of Karma for it!
Watch the Teaser Trailer for "The Lightning Thief" Her
First off, there's nothing a Dremel can't do.
But since your alternative involves electricity, water, and chemicals, we'll forgive it. (But next time, could you kindly use something more dangerous than sodium chloride? We've got reputations to uphold here, and if the case mod weren't so danged cool, we'd feel we were slipping.)
Now, instead of merely cutting myself, I can electrocute myself as well. I love case modding!
Well, either they've taken their site down, or the "Slashdot Effect" has kicked in. They're gone.
;)
Rats! I wanted to see how this works - suprise my boyfriend by etching the fenders on his 69 Mustang
2 cents,
Queen B
HDGary secures my bank
Let's see your fancy "salt water" and "electricity" do this!
http://trigeek.net/mirror/etch/guides.php.html
What a true geek would do is build their own computer-controlled laser cutting/etching rig, a few of these together should cut through aluminium or mild steel no problem :)
I'll try to summarize this since I managed to read the first few pages before the horde of slashdot ate the website.
You take two plates of metal and hold them parallel (not with your hands, they're going to be electrified!) underwater. Electrify the plates and the positive ions in the water will collect at the negative terminal and the negative ions will collect at the positive terminal. By adding some salt to the water however, you can encourage a chemical reaction to happen at a given electrode. By covering the metal with paint or duct tape, you insulate it from this effect. So what they're doing is, essentially, painting around the hole they want to cut, leaving the hole itself barren, then submerging it in saltwater and electrifying it, causing the exposed metal to oxidize and be eaten away.
It's roughly the opposite of electroplating, which is the procedure which this technique is likened to in the article. Instead of trying to accumulate more on a given electrode you're trying to reduce the amount of matter present there.
Reinvent the wheel only at either a lower cost, greater effectiveness, or your own personal enrichment and satisfaction.
how do you produce methane from NaCL, H2O, and Fe ???? I think only H2, and O2 are emitted!!
Yeesh, you would have thought the kid would atleast have worn long sleaves and a face mask (welding mask)... They did this on Mythbusters and the fragments when into the human flesh like gel about 2inches...
One of my friends reminded me the other day of a time when he was making his cooling system. After a while of playing, his computer made wierd noises, and so by looking through the case window we could notice that his cooling system did not work. Basically it looked like a carwash inside his computer. I feel that the best case designs come from mistake, even though that mistake cost him his wonderful computer parts. But lego cases look cool too.
I thought what I'd do was, I'd pretend I was one of those deaf-mutes. - Catcher in the Rye
Kinda apropos, dremel has a Case Modding Project on their website. They cut the word DREMEL into a case. Looks nifty.
FeCl3 is cheap, relatively safe (don't eat it kids!), and easy to handle. It stains like a bitch though, and will attack most metals so be careful with spills.
Works on brass too. but its harder to get ahold of that stuff nowadays. Drano will probably work faster on Aluminum and not require electricity but you got to play with the concentrations or the process will heat up so fast it will melt your resist.
SLASHDOT: news for people who can't concentrate on work or have no life at all and got tired of yelling back at the TV.
Not directly dioxins, but it does make covalent chlorine, which often ends stabilizing as dioxins. Even if it ain't that, its still BAD (worse than not putting comments in code, Broken As Designed).
Unfortunately, I was unable to load the article - so I can't comment on the procedure involved. But if you haven't studied electrochemistry to at least a small extent to know whats going on (and I know people with B.S. in chemistry I wouldn't trust with understanding reactions in this catagory), its best you DO NOT try this. The procedure listed may be completely harmless, I can't say without having access to reading the procedure. But if you are someone (like most slashdotters) who doesn't hesitate at "improvising", stick to the dremel.
This is a terrible guide. Several times he says "make sure you know what you're doing" but offers no help or explanation. It is poorly worded and offers little guidance. The pictures do not help at all, either. Does anyone know of a better guide for electrolytic etching?
Easily done. Head to Techniks or some other similar place and get some Press 'n Peel PCB transfer film.
Draw what you want to etch as a negative and then iron it onto your metal. Dip the whole thing in the acid bath and wait a bit. Steel wool to clean off the resist and that should do it.
If you're really cheap, toner is a decent resist. No different than making a homebrew PCB.
Weaselmancer
rediculous.
Cover the "canvas" with masking tape. Draw your design. Cut out your design with a sharp X-Acto blade. Etch the exposed design with a bead-blaster (like a sand-blaster, but uses smaller, more uniform glass beads, and doesn't eat away as much, as fast).
Been doing this for years.
"I might have made a tactical error in not going to a physician for 20 years." -- Warren Zevon
I managed to grab a link out of the page from mirrordot before it went tits-up again. This is the link the guy got part of his idea from.
http://gravert.club.fr/galvetch/contfram.htm
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This technology is nothing new. My father built systems to do R&D and production using Electro Chemical Machining. [...]
Items used every day may have under gone this process, turbine fan blades, air bag explosive chambers, hard drive motors (meow), test sabot rounds for tanks.
Are you sure those are all built by electrochemical machining? I suspect some of them are built by its close relative: electrodynamic machining.
Electrochemical machining is reverse electroplating. It pulls metal atoms out, not just from the cut, but from the surrounding metal that is intended to remain, changing its properites.
Electrodynamic machining is a spark to the workpiece through a dilectric solution (typically water or oil). It can cut through anything that can be made to conduct. (You do diamonds by flashing a bit of metal over them for the initial contact. As you're removing diamond, the surface that's left has a microscopic layer that is converted to graphite to keep you going.)
Three sorts of tools:
- Use the end of a wire as a drill. (Feed the wire as the end erodes.)
- Use the side of a wire as a bandsaw. (Feed the wire in the inches-per-minute range so the cutting edge is always smooth and of a known size.)
- Make a graphite electrode in the shape of the hole you want and burn your way in. (Graphite doesn't erode much at all. Replace as needed.)
Cutting action: The spark vaporizes a path through the dilectric and melts a tiny pit in the workpiece. (Polarity is chosen so most of the melting is on the workpiece.) When the spark stops the channel collapses and the shockwave blasts the molten material out of the pit before it can re-harden. Repeat at a rate in the kilohertz range. Spark generally forms at the shortest space, which is where you want to remove the most metal, giving you a mirror finish.
(This effect was originally discovered in Russia about WW II when an engineer tried increasing the life of ignition "points" by putting them in an oil bath to cool them. They disintegrated within hours. It's also why you always use a brush to run current around a lubricated ball- or roller-bearing instead of passing it through the bearing: The effect would destroy the bearing surfaces in a similarly short time.)
The cut-away material ends up as a contaminant in the dilectric. So you pump that through a filter to clean it out.
Motion control is paramount: You sense the spark voltage to tell how far you are from the workpiece and use it for feedback, advancing or backing up to keep your spark path at the correct length.
Contaminants (especially chips) sometimes short the gap, so you back out until you clear it and can spark again. Sometimes you end up machining away the chip. Sometimes you may have to back far - even completely - out of a cut to clear the contaminant from your gap. This may mean retracing your path around several turns. (In the shaped-carbon-rod drill-in mode you also run the rod in little circles and/or back-and-forth it now and then to pump the dirty dilectric out and clean stuff in.)
You're CONSTANTLY backing-and forthing. MOST of your tool motion is back-and-forth, a small fraction is motion into the workpiece as the cut advances. So you MUST use an integer motion-control algorithm that retraces its steps exactly (or within an LSB or so) and doesn't accumulate roundoff err. Any accumulated roundoff, even a TINY bit, quickly walks you out of your path and into the workpiece, shutting you down.
The device is essentially a big power supply, a resistor, a switch, a voltage measurement peripheral, a computer, a motion table, and a dilectric pump/filter. Most of the energy ends up in the resistor. You do it that way as the easy way to control the spark's waveshape. The switch might be a bunch of paralleled FETs on a big heatsink. The resistor might be a bunch of foot-long power resistors, with a fan blowing on them so you can run them far beyond their normal ratings, carefully wired to minimize parasitic inductance.
That's the bulk of the specialized knowlege you'd need to build one, as they were about 15-20 years ago (when I did software for one).
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Roughly speaking, you don't use acid because you would need too much of it, and it sucks at cutting, and at giving neat edges. Oh, and resists are difficult, and it's slow.
Resists: You need something that is resistant to the acid, but can be applied neatly, and removed neatly afterwords. It needs to adhere well to the metal surface, yet be resistant to the acid and to water, and any by-product produced. Also, it needs to be resistant to exfoliation - as you start to etch, it's no good if your resist falls off around the cut. Oh, and it needs to be cheap and easily available.
Rates: Acid is slow. Or, rather, acid's that you would want to use for this purpose are slow. Anything that can eat through steel or aluminum at a decent rate is not something you want to handle. (Consider: What do you store it in, and what do you do the reaction in? Both are doable - but not strightforward). So you're left with acids that don't eat the metal very fast.
Edges: With an electrical current, you can ensure that the direction of cutting is more or less perpindicular to the surface of the metal (that's why it's two large plates, for example). With an acid, that's not the case. They will tend to etch out round indentations under the edges of the resist - giving you razor sharp edges to your cut out. Which would need filed down afterwords, and means there is a minium thickess of cut, proprtional to the thickness of the sheet.
My back of envelope sums suggest that the miniumum width of cut by acid etch is roughly equal to the thickness of the material, assuming an infitessimally small start. For 1.2 mm sheet metal, that's a 1.2 mm width - easily doable with a Dremel.
It would also take around 3-4 months, I think.
Acids are good at etching a surface layer. I would use an acid if I wanted a matt surface - for example, to etch details onto sheet metal. A combination of cut outs and etching would work very well in giving a unique appearence to a panel.
Using salt for this will produce chlorine in addition to oxygen.
Use baking soda or sodium hydroxide instead. Either electrolyte will give off substantially less-dangerous byproducts.
p
In Korea, long hair is for old people!
A REAL geek would use Explosive Forming.
The 40% solution mentioned in the article probably limits the strength.
Keep it off of your 501's or we will know you can't use a Dremel tool.
From: Electrochlor.com
1.2 Reactions
The principle reactions occurring in the electrolytic cell that produces sodium hypochlorite are quite simple, as shown in the following:
Oxidation of the chloride ion occurs at the anode:
2Cl- -> 2Cl2 + 2e-
Followed by a rapid hydrolysis of the chlorine:
Cl2 + H2O -> HOCl + HCl
Reduction of the sodium ion occurs at the cathode:
Na+ + e- -> Na
Followed by a rapid reaction of the sodium with water:
Na+ + H2O -> 1/2H2 + NaOH
The acids (HCl and HOCL) produced at the anode react with the base (NaOH) produced at the cathode:
HCl + NaOH -> NaCl + H2O and,
HOCl + NaOH -> NaOCl + H2O
The net reaction of electrolysis is:
NaCl + H2Oe- -> NaOCl + H2
The amount of hypochlorite produced is related directly to the amount of direct electrical current passed through the cell.
Easier to read on web site. I had to hack in '->'s.