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Want a Cool and Quiet PC? Dunk it in Oil
The Last Gunslinger writes "Tom's Hardware Guide has published an article (complete with video) showing how they employed their own approach to the liquid cooled computer. To offset the loss of normal airflow around their Athlon FX-55 and GeForce 6800Ultra, the mad scientists in the lab decided to fill the case up with 8 gallons of cooking oil. The oil temperature leveled off at a comfy 104F during benchmarking operations intended to tax both the CPU and GPU to their limits. Interestingly enough, they first attempted this operation using deionized water. It worked for 5 minutes before developing short circuits...but the hardware was amazingly undamaged." Slashdot has covered similar projects in the past but it was neat to see the differences in oil and the look at capacitance around the CPU pins.
No pics left but archive.org does have a few pages achived from a guy who subsubmerged his Celeron 333 in oil back in 1999. I'm sure even earlier attempts exist...
s data.com/drffreeze/FAQ.htm
http://web.archive.org/web/19991122030011/www.acc
Also, vegetable oil is a good solvent for a lot of polymers. And I imagine that there are several oil-soluble polymers on a motherboard. It might not dissolve them quickly, but it'll do it eventually.
It's not the water that damages electronics but rather the salts and other ions in the water that allow short-circuiting, and if concentrations are as high as in tap water will often leave conductive salt bridges between pins. (Washing ciruit boards in the dishwasher can be ok, though, if you know what you're doing.)
Deionized water temporarily has no ions but disolves some out of virtually anything, making it an undependable resistor. It also has a whopping dielectric constant that would be a bad idea in any case for a bath for high-frequency circuits designed to run in air.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
Tranformers have used oil for a very long time for cooling. The problem with putting it in a computer case is that over time the oil would most likely work its way into the slots on any cards you have installed and cause the system to stop working. And you have the maintance problem, you want to upgrade that video card but now you have several hours job of draining the oil, removing the existing card, cleaning the slot connectors carefully, installing the new card, sealing the system up, refilling with oil, only to find out that you forgot to set the options on the card correctly, back to step one.
BTW: I saw a tranformer on a pole catch fire once. Spit oil and other stuff all over the cars below it. Very impressive.
Brake fluid (Dot5, silicone based) seems like it would be a good candidate.
Dot3 has awesome heat transfer ability, but collects water, and plays hell with paint (I imagine sensitive electronics to feel similar pain).
Silicone is a dielectric, right? How about PEG? http://en.wikipedia.org/wiki/Polyethylene_glycol
We've been immersing electronics in oil for decades. Difference is, we build sonar systems, so we're doing it so the electronics can survive a high-pressure environment, and also because oil provides lots of heat sinking and you don't want to put fans and such in a sonar receiver. Like others have posted, though, it gets heavy: one of our units is only about as big as a Shuttle XPC box but weighs over 75 pounds.
I haven't seen the rancid oil problem, but we've only used a couple kinds of oil: a synthetic type (I'm told it's often used as a base for cosmetics), and castor oil. I have seen circuits change their operation when submerged (due to increased capacitance), but only once: a microprocessor reset controller changed its timing (it used a capacitor connected to a pin to determine how long to wait before letting the machine out of reset). You just have to be careful and watch for these things when designing the circuits.
Water leaks are bad, though water will tend to head down to the bottom. Our equipment is usually made to much tighter specs than any PC case, though (titanium housings and electron-beam welding, and sometimes an anti-corrosion coating). You get what you pay for.
A couple of things we deal with that your average PC builder won't: we have to forgo the use of any component with air inside it (e.g. aluminum can-type capacitors, some clock oscillator chips, really big power transistors), since they'll collapse under pressure (thousands of pounds per square inch), and we have to put a flexible window (or something similar) on one side of the enclosure because the oil volume will change with temperature.
Also... that oil gets on everything, man. No fun to work with. At least it doesn't smell too bad when you have to solder through it. But your hands feel greasy for the rest of the day, even after washing them.
I should call 3M and see if they can find me a non-conductive, inert, non-volitale chemical to submerge a PC in. I'm sure they make one.
You should. But I'll save you the trouble.
It's called 3M Fluorinert, and now that it's come up in two separate discussions in two days, I now know more about the stuff than I ever wanted to. (Great use of company time, eh?)
This is the 3M page about it, they make a bunch of different varieties for various purposes. I believe what you'd want to use on a computer is the '77' variety. (I'm told that's what the Cray II used.) 3M Fluorinert
Some people who will sell it to you in small quantities (3M wants you to buy 11 lbs.)
And here's the obligatory Wikipedia entry: http://en.wikipedia.org/wiki/Fluorinert
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
if it's good enough for x-ray and broadcast transformers and particle accelerators, it's good enough for your pc. it's less likely to grow crud, very much less likely indeed to harbor water, and readily availiable.
if this is supposed to be a new economy, how come they still want my old fashioned money?