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Originally Posted by Jabo
The problem is that with so high forces materials needed would need to be very 'strong' = dense = good thermal conductors  . There are two ways of increasing thermal resistance, either change material or reshape it |
You are right about changing thermal resistance, that's why I suggested changing materials. Reshaping is not always an option, so you should really be considering thermal resistivity, or conductivity, which are material properties and are not affected by shape.
That's not exactly a good correlation between strength and thermal conductivity, density has little to do with either. And from my calculations, by applying 300PSI of pressure to two 50mm^2 peltiers, you would need a #4 washer to withstand compressive pressure of about 10,000PSI, or ~70MPa in "those other units". According to this materials database software that I'm using, nylon ranges from 55-104MPa in compressive strength. So nylon might actually work just fine, depending on the washer's specific properties and how the pieces are assembled.
Considering both compressive strength and thermal conductivity, here are some of the viable options that the software suggests...
Polymethylmethacrylate (PMMC, Acrylic)
Polyamides (Nylon, PA)
Polyetherketones (PEEK)
Titanium - only 5-12W/m-K and definitely strong enough
And then some kind of wacky materials that would never fly due to manufacturing issues... Brick, various glasses, bamboo, stone.
