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| RTV copper silicone as thermal compound? |
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| smile:
Hello, might be stupid question but given the price are these RTV silicone sealants that claim they have copper in them can be used as liquid thermal pad? Thermal adhesive silicone? Supra Copper Gasket Maker - Permatex Copper rtv silicone gasket maker -DoneDeal many more brands, the MSDS does not mention copper maybe because it is no harmful? Or it's just marketing crap? |
| wraper:
Liquid thermal pads do not cure like RTV silicones, they remain mushy. If you need adhesive in particular, RTV silicone can be used for that. You need neutral cure silicone to use anywhere near the electronics and most of them emit acetic acid when curing. Permatex appears to be fine. DoneDeal says "Sensor safe when cured" which is very suspicious wording, no datasheet too. Normal RTV silicone can be used as thermal interface if heat dissipation and thickness are not high. Generally you can expect about 0.2-0.3 W/mK thermal conductivity, although some are significantly worse. Don't use it between two wide pieces of metal as it will take forever to cure in the middle. Wide plastics are generally fine as they pass moisture to some extent. If you need high thermal conductivity, there are some special silicones. Do not expect any outstanding thermal conductivity unless there is exact number in the datasheet. If silicone say contains only 10% of copper, it won't improve thermal conductivity too much. |
| smile:
Well the wmk is very unreliable. ARCTIC G-1 - Thermal Compound. 4.3 wmk.. 6.3Eur for 9grams No longer manufactured, the manufacturer must have unlearned how to make thermal glue in 2023. Not that it would be true 4.3wmk but was not bad in year 2011, at the price is sold it great too. Why Arctic no longer makes it they make no alternative is very strange. Regarding RTG copper gasket makers - same thing how much copper nobody knows. I think better use copper powder etc. and RTV silicone or better two component silicone. But it's not available at small quantities |
| wraper:
Filling Silicone with powder won't do the job. You can add only so much until it becomes unusable. If you say add 30% copper, it should be like 1mm thick layer of this concoction performing like 0.7mm of pure silicone. Which is not great at all. |
| smile:
How so 30% only, if the particle size is 1/5microns then the copper content can be about 70% at least. This is based on my experience with aluminum powder and epoxy. The aluminum powder is coated with oil and will not cure in silicone sealant of any kind. |
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