Thermal adhesive

[libraryman]

I am considering using  Artic silver thermal adhesive to attach a peltier pad to a cold finger then the heat sink to the hot side of the peltier using the same adhesive.

Has anyone used this type of attachment, it looks very feasible on the face of it..(pardon the pun) and it helps to reduce the size of the cold finger face!

Ray

[russellhq]

I've not tried this, but is the idea to avoid a clamping arrangement?

[Gina]

Haven't come across this stuff before - looks interesting   I have had problems with the TEC sliding out of place so gluing it to the cold finger could solve it.  Bear in mind though that this is a permanent adhesive so if the TEC fails you'll need to replace the cold finger as well.  I see it's a two part adhesive so I think it's probably an epoxy resin.

[Mr TamiyaCowboy]

the thermal exchange foam pad tape. 

hmmm. to be very honest i would stay well clear, it was used to hold heat sinks onto 

computer graphics cards memory chips. it will work but no way near as effeicent as thermal compound

arctic silver compound is a thermal GREASE , a heat exchange grease.

the way we use it in electronics is as a thin thermal compound. we use very little

grease and allow suction pressure to hold it roughly inplace, we the use a spring

based clamp system to hold the heat sink unit to the face of the chip/s.

over time the grease can dry up and need replacing ( isopropol alcohol removes it)

to keep up the best thermal exchange qualitys possible. Cameras are an inherent pain in the rear to cool

its not the placement of cold fingers, but keeping them inplace and clamped to sensor and chipset surfaces.

grease up the hot plate side , use a small ball in the center of the TEC. 

use an old credit card/marge tub, to smooth the past evenly over the surface.

marry up the heatsink ( clean this puppy with isopropol alcohol beforehand )

press the two together give it a little wiggle as you do. 

holding the two together without spring clips ? i have seen older computer systems using a C clip

clipping to the underside of a raised chip and into a small runner rail on the edge of low profile heatsinks.

using a plastic c clip could be a way to go 4 clips, two clips on one side two on the other. 

i have a heatsink here its a 45x45mm x8mm deep alloy grid vane type, but it has a four c clip attachment system.

gap between heatsink face and clips would hold a 3-4mm thick tec plate

[libraryman]

Thanks all for the replies, yes the idea is to avoid clamping, you can indeed get Arctic Silver thermal adhesive, it is not the same as the grease type, it's a two part resin and as Gina say's it sticks like the proverbial.

I suppose it comes down to testing it, i am hoping that it's thermal qualities are similar to the paste! Solder is another option as long as the temperature required to melt the solder does not stuff the peltier!!

The thermal pads are another method but i believe less efficient thermally! 

Ray

[russellhq]

Ray, the thermal performance of the grease is so low compared to the actual heat sink ( it's in the order of 5 vs 400), you're not really going to notice a difference.

The greases work by filling microscopic voids and surface imperfections between the 2 surfaces. When you apply the grease, you should still be able to see the surface you've just coated, but it will just look slightly dull.

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

It's a bit misconception that thermal grease is a good conductor of heat, it's actually pretty poor, but compared to the air it's replacing, it's relatively good.

[russellhq]

An interesting read of various mounting methods:

https://thermal.ferrotec.com/technology/thermoelectric/thermalRef06

[libraryman]

Thanks for the link Russ, i had found this and decided to try the thermal adhesive, just waiting on the copper for the finger and i am considering one of these  AK-351-2  as the heatsink!!

what do you think..will it do the job?

Ray

[russellhq]

Thanks for the link Russ, i had found this and decided to try the thermal adhesive, just waiting on the copper for the finger and i am considering one of these  AK-351-2  as the heatsink!!

what do you think..will it do the job?

Ray

It looks neat but I don't think it'll be up to the job. This is a good site for cpu heatsink reviews: http://www.frostytech.com/

Here's the one I got:

http://www.frostytech.com/articleview.cfm?articleID=2587

[libraryman]

Thanks Russ, I took the example from that excellent website showing the very pro looking 550d mod, that camera only uses a small copper heat sink, though its heavier, it should be more efficient, its quite cheap as well.

On that example it looks as though neoprean has been used to insulate the cold finger!!!

Tidy and possibly very effective?

Ray

[russellhq]

Thanks Russ, I took the example from that excellent website showing the very pro looking 550d mod, that camera only uses a small copper heat sink, though its heavier, it should be more efficient, its quite cheap as well.

On that example it looks as though neoprean has been used to insulate the cold finger!!!

Tidy and possibly very effective?

Ray

Yes, that's a very nice example of a cooled camera. I think it's completely possible to use a small heatsink, but you have to insulate well so you keep the heat load on the TEC as low as possible otherwise you won't get nice low temps. The heatsink and fan in my QHY8L proves my point:

This easily achieves a delta of 35C with what looks like a basic heatsink and 50mm fan.

The insulating used on the 550D looks like Armaflex which I've used before and is very good. You can buy it in tape rolls or as self adhesive sheets.