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heat conducting glue??

Posted: Tue May 12, 2009 2:53 pm
by POLAND_SPUD
what can I use as a substitute of thermal glue?? (you know the thing used to glue the CPU and radiators)

I won't use thermal glue becasue it's very expensive (well at least here it is) and I need to use a lot of it

any ideas ?

ohh just in case you need this info - I want to join copper with the outer shell/casing of a fridge compressor

Posted: Tue May 12, 2009 3:11 pm
by ramses
there is this radiator repair stuff. It is basically a glue with aluminum powder in it.

Posted: Tue May 12, 2009 3:15 pm
by Biopyro
Does it actually need to conduct well, or just be heat resistant?
I take it it doesn't need quite the conduction of the CPU glue?

You could use flue sealant or something similar with metal powder in it to aid conduction.

I think it's expensive everywhere though :(

Posted: Tue May 12, 2009 3:24 pm
by POLAND_SPUD
@ biopyro
Does it actually need to conduct well, or just be heat resistant
well I don't expect it to work as good as commercial thermal glue... I need something that conducts good enough... or better than most glues (which AFAIK are no good at conducting heat)

Posted: Tue May 12, 2009 3:24 pm
by SpudFarm
woow! you need a lot of thermal paste there!

considered getting a big CPU or GPU/VGA heat sink?

just modify it untill you get the surface area you want from it..

or you can get a crappy one and use only the heat pipes to conduct the heat away and into your cooler.

Posted: Tue May 12, 2009 3:25 pm
by jimmy101
Most glues are at least OK thermal conductors, actually, pretty much any solid that doesn't include a lot of entrained air is about the same when it comes to heat conduction. Metals tend to be much better heat conductors but metals don't occur in glues too often.

Any mucky substance that is semisolid and won't melt at your temperatures can be used for the thermal conductor. Something like axle grease would be one possibility.

One easy way to add copper to the outside of the compressor would be to just wrap 1/4" soft copper pipe around the pump housing. If you need serious cooling you can pump water or air through the pipe. Another possibility would be to use the copper pipe as a clamp to hold copper cooling fins in place.

Posted: Tue May 12, 2009 3:47 pm
by POLAND_SPUD
I do have one heat sink and it seems quite effective at disipaing heat... the problem is that the casing doesn't have a lot of flat surface to attach it so I need some glue that can fill the gap

I also have at least several kilos of short strips of copper sheet (AFAIK they are used for securing sheets of glass in greenhouses or soemthing like that)

I already have a CPU fan and it's quite good at doing its job but I suppose that I could do without it if I could greatly increase the surface of the compressor casing by attaching the radiator and the strips...

Posted: Tue May 12, 2009 3:54 pm
by Biopyro
I would just try a couple of CPU heatsinks with fans. How bad is your overheating problem?

If you have some soft copper tube, definately get some water pumped through and some airflow past it.

Have you considered putting it in a fridge? :P

Posted: Tue May 12, 2009 3:56 pm
by SpudFarm
you know what? putting the whole compressor in a TIGHT plastic bag and then submerge it in cold water will be quite effective. it should cool it's core as normal with the air sucked through it. but with the added effect of water it will run cool.

water is a liquid annd we all know that liquid is a good cooling medium.

Posted: Tue May 12, 2009 4:04 pm
by POLAND_SPUD
overheating can be a problem if one uses it for longer than 40 minutes or so... the problem is not that they produce a lot of heat but that it's difficult to disipate it since the casing has rather small surface area

I have tried a sort of 'overkill approach' first - I used a large fan and the firdge was only slighly warm but the point is that I am looking for other ways of doing it - just in case I'll ever want to turn it into a two-stage pump that can genereate higher pressures (and most likely more heat as well)

of course I can use a 90W fan do do the trick, immerse the whole compressor in oil or use water cooling but I am trying to find new, better, less energy consuming and easier ways of doing it

@spudfarm
water and electricity don't go well toghether... I did consider this idea but it's too dangerous... I want to see if larger surface area can do the trick... I want a maintenance free cooling and I just need to find material that can conduct heat effectively and I hope that jimmy is right

Re: heat conducting glue??

Posted: Tue May 12, 2009 7:08 pm
by Technician1002
POLAND_SPUD wrote:what can I use as a substitute of thermal glue?? (you know the thing used to glue the CPU and radiators)

I won't use thermal glue becasue it's very expensive (well at least here it is) and I need to use a lot of it

any ideas ?

ohh just in case you need this info - I want to join copper with the outer shell/casing of a fridge compressor
Due to the relatively low Watts/sq cm in a compressor, a super low thermal resistance is not needed. The same way crankcase heaters can be used on compressors, a cooling tube can be attached. For portable use, a simple 2 part epoxy can be painted on and then the copper tubing can be wrapped around the compressor shell. Remember the compressor inside the shell is not bolted to the shell, but is suspended on springs to keep the noise down for a refrigerator. The thermal conduction is simply through an oil bath. Your goal should be to simply keep the oil cool. The cool oil will keep the compressor cool.

A fancy water block is not needed in this application. The heat density is not high enough to require it.

Posted: Wed May 13, 2009 6:35 am
by psycix
Biopyro wrote:Have you considered putting it in a fridge? :P
Where'd you get that idea? Nobody would do such thing. :D
Image

I have to say, this cooled him down quite fast!

Posted: Sat May 16, 2009 1:48 pm
by POLAND_SPUD
Superglue conducts heat (not as good as I would like it to do it but it works)
attaching the radiator was rather easy and it works quite good at dissipating heat - I could feel that metal around the radiator was slightly cooler than on the other side of the casing

copper strips also seem to work good but after attaching 10 of them I realized that turning the compressor into a hedgehog doesn't make it look neat at all... at least now I know that it's possible to cool the compressor without using a fan

I think I'll have to find a better way of attaching the strips :?

Posted: Sun May 17, 2009 6:23 am
by psycix
Not to mention it makes the damn massive thing even heavier then it already is.
For ultimate cooling, drill two holes in the bottom and attach pipes/hoses which lead to a pump and a radiator. Then you can pump the oil through the radiator to cool it, and the oil effectively cools the insides.

Posted: Sun May 17, 2009 10:27 am
by POLAND_SPUD
yeah that would be the most effective method at least it seems so... I think that drilling the holes would take a lot of time

but it seems rather time consuming and complicated when it comes to using several compressors at once I think that it would be the best idea to put them in a sort of a box, like a CPU chasis - with vent holes and place a big ass fan on top of it