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Vacuum sealing the mobo?

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Daedlus

New Member
Joined
May 15, 2001
I keep seeing warnings about peltiers and the nasty effects of condensation. As I understand it, condensation is water vapor drawn out of the surrounding air that is at a higher temp than the condenser. That being said, why not eliminate the air all together? that way, there is no issue/problem of water vapor.

Now people may say "Daedlus, you might end up insulating the chip if you put it in a vacuum."

Here is my (tentative) answer.
Get some sheets of lexan or lucite, and find a friend who has the cutting implements that the job would call for. fashion a box that fits around the mobo, leaving clearance for the pci slots etc. We may just want ot encase the upper half od the mobo, and leave breathing room for the ram slots and all of that. This could also be a multi compartment box. whatever. once we get the form down, we make sure that the peltier and water cooler will fit (for the cpu and the northbridge), either flush with the top of the box, or just inside it. Then we take all large amount of rtv silicone and start gooping it on all of the potential openings. we install a pressure valve somewhere on this box, preferably in an easily reached area. We then test the bugger out by hooking it to a vacuum pump and sucking all of the air out. IF the vacuum holds, we then take the box to the local fire station, and have them pressuize it with CO2, or nitrogen, or whatever non-explosive/ non-corrosive/ non conductive happy gas that we can think of that will hold the nasty air at bay.

Then we can crank the peltier and cpu to insane levels.

what is the weak point in this plan?
 

[Oc]acaridans

Senior Member
Joined
May 11, 2001
does Co2 hold moisture? i dont remember....i wouldnt reconmend using nitrogen due to it explosive nature... the biggest problem is sealing it...rtv wont work it would get ripped off...the reason vacume chambers are round is the fact that the pressure is spread out evenly...a case would colapse in on itself as soone as you started sucking the air out....if you want to do a extream cooling setup id reconmend, a liquid N rig...my 2 cents but if youve got an old computer laying around try it...id love to see how it works
 

NightFire

Registered
Joined
May 18, 2001
It would probably be easier to get a de-humidifier, and remove the moisture from the air. (I would suggest not actually working on any electronics equipment without at least normal humidity levels though.)
 

CreePinG_DeatH_reverted

Registered
Joined
Dec 22, 2000
Well the problem is that the Peltier would nuke itself and the CPU in a second. How would you remove the heat from the peltier? And then from that device? Point being air is what usually cools everything. Now you might be able to get a water block to pump through some strong tubing into the vaccuum chamber, just becareful because air helps a lot more than one might think.
 

ken257

Senior Member
Joined
Dec 20, 2000
Conformal coat and insulate + some dielectric grease. This is a much easier and practical solution. I run my cpu sub-zero and have no problems with condensation.
 

Thelemac

Administratively Deficient
Joined
Mar 15, 2001
CreePinG_DeatH (May 30, 2001 08:23 p.m.):
Well the problem is that the Peltier would nuke itself and the CPU in a second. How would you remove the heat from the peltier? And then from that device? Point being air is what usually cools everything. Now you might be able to get a water block to pump through some strong tubing into the vaccuum chamber, just becareful because air helps a lot more than one might think.

Well, air is what is commonly used. To worry about condensation from a pelt, though, you're gonna have to be watercooling that...

In this case, the heat is being transferred directly to a coldplate, which gives it to the tec, which gives it to the waterblock, which gives it to the water, which takes it to the radiator (assumed to be outside the vacuum) which gives the heat to the air.

It would be easier and more practicle to go with a nice conformal coat and grease and such as ken257 mentioned. Though if you really wanna vacuum seal or just fill an airtight container with some gas (0% humidity air, for instance) then more power to you! It's not always the praciticality that drives us to different ideas, but the fun in doing so.
 

surlyjoe

Senior Member
Joined
Dec 27, 2000
Location
far west
thats an interesting idea , if you could just put like a tupperware bowl over the CPU area and seal it up good and force the air out with a gas that was moisture free it should work fine,, if your gonna try it lemme know ,,,if not I may
 

Fink

Member
Joined
Dec 18, 2000
First, nitrogen is not explosive....

Argon would be a far better choice as the replacement gas. Argon, being much heavier than air will displace air from a container. Argon will 'pool' at the bottom of the container and push the air out the top. We use this principal on a daily basis to work under dry atmospheric conditions - a must when your chemicals ignite when in contact with moisture. Argon is also cheap (~$40 for 235 cf) and readily available in a highly dry state (for some extra$$). Nitrogen (the un-explosive kind), being a large percentage of air, will not displace the air, but will just mix with it, this makes getting all the moisture out difficult but it is cheaper than argon but typically contaminated with water

Another problem not mentioned, is moisture on the component surfaces - there can be a significant amount of water adsorbed onto metals, silicon and especially ceramics. In the lab, we usually remove this adventitious water by heating the glassware to 140C overnight or drying the glass over a propane/air flame followed by purging with argon - works great, with glassware. Problem with electronics though, won't handle the heat.

You can dry non-heatable items by a number of alternate methods. Using the pump-purge method, the equipment is placed in a sealed, airtight bag, is pumped down to 0.1 torr vacuum ( 0.1 mmHg) and the bag filled back up with your dry gas of choice (argon), repeat x3. Viola! 99% of H2O gone. OR, if you do not have access to a vacuum pump, place your components in a plastic bag or Tupperware with a saucer filled with a desiccant and seal it up. Depending on the aggressiveness of the desiccant, 2-5 days should be sufficient for H2O removal and you really do not need to use argon. I can recommend calcium chloride or silica (as long as you dry the silica first) as commonly found desiccants. Drop me a note if you want to know how to find them in the store. The baggie-dessicant method would work great for this experement, as you could cut holes in the bag and seal them with silicon (acetic acid free silicone), allowing you to pass cables through. You would still have to extract the heat somehow though…. Plenty of ways to do that….

We do this kind of 'dry' work every day and there are a large number of techniques we can use to dry unusual components. Heck, if I had a TEC and PS, I would try this myself…. Great Idea!
 

Fink

Member
Joined
Dec 18, 2000
First, nitrogen is not explosive....

Argon would be a far better choice as the replacement gas. Argon, being much heavier than air will displace air from a container. Argon will 'pool' at the bottom of the container and push the air out the top. We use this principal on a daily basis to work under dry atmospheric conditions - a must when your chemicals ignite when in contact with moisture. Argon is also cheap (~$40 for 235 cf) and readily available in a highly dry state (for some extra$$). Nitrogen (the un-explosive kind), being a large percentage of air, will not displace the air, but will just mix with it, this makes getting all the moisture out difficult but it is cheaper than argon but typically contaminated with water

Another problem not mentioned, is moisture on the component surfaces - there can be a significant amount of water adsorbed onto metals, silicon and especially ceramics. In the lab, we usually remove this adventitious water by heating the glassware to 140C overnight or drying the glass over a propane/air flame followed by purging with argon - works great, with glassware. Problem with electronics though, won't handle the heat.

You can dry non-heatable items by a number of alternate methods. Using the pump-purge method, the equipment is placed in a sealed, airtight bag, is pumped down to 0.1 torr vacuum ( 0.1 mmHg) and the bag filled back up with your dry gas of choice (argon), repeat x3. Viola! 99% of H2O gone. OR, if you do not have access to a vacuum pump, place your components in a plastic bag or Tupperware with a saucer filled with a desiccant and seal it up. Depending on the aggressiveness of the desiccant, 2-5 days should be sufficient for H2O removal and you really do not need to use argon. I can recommend calcium chloride or silica (as long as you dry the silica first) as commonly found desiccants. Drop me a note if you want to know how to find them in the store. The baggie-dessicant method would work great for this experement, as you could cut holes in the bag and seal them with silicon (acetic acid free silicone), allowing you to pass cables through. You would still have to extract the heat somehow though…. Plenty of ways to do that….

We do this kind of 'dry' work every day and there are a large number of techniques we can use to dry unusual components. Heck, if I had a TEC and PS, I would try this myself…. Great Idea!
 
W

William

Guest
hmm, we are not approaching this logicly. I thought about this a while back, and the best way to do it is to vacuum seal the ENTIRE case in something else. Then let air in through a dessicant tube filled with something like anhydrous calcium chloride. MUCH cheaper than Argon or Nitrogen(which is inert and does not expload at all). So you just use air, and dry it it out before it gets into the case. Thus, no water vapor to condensate.
 
W

William

Guest
well you can heat the area the comp is in and bake at say 80F which a comp can stand and just a have a pool of calcium chloride in the bottom. This is what chemists use, its called a dessicator, and they dry crap with it, I think this may be better than argon IMHO as it would probably be even cheaper. You could also dry your argon this way.
 

Fink

Member
Joined
Dec 18, 2000
dunno260 (May 31, 2001 04:47 a.m.):

hmm, we are not approaching this logicly. I thought about this a while back, and the best way to do it is to vacuum seal the ENTIRE case in something else. Then let air in through a dessicant tube filled with something like anhydrous calcium chloride. MUCH cheaper than Argon or Nitrogen(which is inert and does not expload at all). So you just use air, and dry it it out before it gets into the case. Thus, no water vapor to condensate.

The only problem is that even a single 36 cfm fan will pull enough air through a calcium chloride drying tube necessitating replacement of the dessicant in about 1-2 hours. Also, calcium chloride (anhydrous) is not a particularly rapid nor efficent dessicant, a column of activated molecular seives or a conc. H2SO4 bubbler (followed by requisite traps) would be far more efficent. A zero air generator coupled to a large (10cm) drying tube filled with CaSO4 and mol. seives would be ideal.

My original thought was to seal the MB and TEC unit up tight and the bag filled with argon. The heatsinks could then protrude through the plastic so that they may be cooled by air. The tupperware idea that Spode had was good, as it would produce a nice compromise between cooling of the MB by air, but eliminating the possibility of TEC condensation.

well you can heat the area the comp is in and bake at say 80F which a comp can stand and just a have a pool of calcium chloride in the bottom. This is what chemists use, its called a dessicator, and they dry crap with it, I think this may be better than argon IMHO as it would probably be even cheaper. You could also dry your argon this way.

Well, that is what I said. You don't need to heat it though, just give it 24+h in the dessicator and it should be dry enough. Anhydrous calcium chloride is a salt, when it turns into a liquid it is the decahydrate.
 
W

William

Guest
well on the chemicals, i just used CaCl2 as the example cause that is what we use. I see how the H2SO4 bubbler would be very good to use.you don't have to blow air in and out, once it is dried, you just recycle the air in your sealed area. You could make a radiator of sorts to cool the air down and return it to the intake. I don't know, i think just using grease or insulation os SO much easier.
 

UnseenMenace

UnseenModerator
Joined
Apr 23, 2001
What about the financial aspect of doing this? would'nt it be more cost effective to just get a more powerfull CPU and watercool it ?
 

surlyjoe

Senior Member
Joined
Dec 27, 2000
Location
far west
whata ya mean ,,they dont make a more powerful one , and this is gonna be watercooled, with at TEC on it.. :-D
 

mudguts

Member
Joined
Apr 23, 2001
Location
San Francisco Bay Area
This is a great post Daedlus! It really got people thinking! I know I will be mulling it over all day tomorrow at work. Its cool to see how everybody throws in their own ideas on how it could be done. Yeah sure it would be easier to insulate overkill, but thats not as much fun as breaking new ground!
 

Fink

Member
Joined
Dec 18, 2000
dunno260 (May 31, 2001 07:09 p.m.):
well on the chemicals, i just used CaCl2 as the example cause that is what we use. I see how the H2SO4 bubbler would be very good to use.you don't have to blow air in and out, once it is dried, you just recycle the air in your sealed area. You could make a radiator of sorts to cool the air down and return it to the intake. I don't know, i think just using grease or insulation os SO much easier.

I thought about recycling the air too, but worried about keeping the air from heating up too much and how to cool the air down, solves the dry problem though... What you could do would be to add a second TEC, cold end attached to a heatsink and fan to chill the air in the container.

I consider this more of a thought experement, I'm broke and thoughts are, generaly, free. Cheers!
 

NightFire

Registered
Joined
May 18, 2001
Fink (Jun 01, 2001 06:58 p.m.):

I thought about recycling the air too, but worried about keeping the air from heating up too much and how to cool the air down, solves the dry problem though... What you could do would be to add a second TEC, cold end attached to a heatsink and fan to chill the air in the container.

I consider this more of a thought experement, I'm broke and thoughts are, generaly, free. Cheers!


I am working on something like this, sealing the lower part of the case with neoprene, and circulate the air inside with fans. I have 4 TECs w/heatsinks that will cool the air inside the case. I am using that many TECs to keep from overworking them, not to get the air any colder than with just one. When I finish it (read: whenever my wife lets me have more money :) ) I will post it.
 

Mord-Sith

Member
Joined
Apr 4, 2001
If you could get a gas that conducts heat well and make a whole case out of Plexiglass (air tight of course) and just fill the whole case that would work great. You would also have to come up with some form of gas radiator to cool the gas inside the case. You could also use sheets of copper for parts of the case and attach heat sinks hand fans to both the inside and outside of the case.

On a second thought if you just separated the mobo and cards from the rest of the equipment this would make it much easier to cool. You could even use a device like this http://www.ocmod.com/code/show_art.php?id=17&pg=1 with the hot side on the outside of the case and the cool on the inside to keep your mobo cool. You would also need to water cool your video card to keep the mobo temps down.