I have 8 Crydom SSRs (6 40A and 2 25A) with 30A and 15A being supplied respectively. My heatsink is 9.5" x 11.5" w/ 2" fins. Do I just apply a thin layer of thermal compound then attach to the heatsink? Also, will the cheap stuff from the local computer store work or do I need the fancy "Silver Fox" or whatever?
How much thermal compound to apply?
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NoNothing
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The cheap stuff will work
I used to be REALLY into computer overclocking, god I miss my 200% OC's with my phase change unit getting my chip to -50C, maybe that'd work for wort cooling? lol
Anyway, you dont need anything fancy, and just use a thin layer.
Its meant to fill in the valleys created when you press the metal together to create more surface the heat can transfer through.
I used to put a a line on one end of my heatsink, and take a razor and spread it out thin, and be good to go. You can put a dab in the middle, and press the heatsink on your SSR and get the same results.
As another side note, I found in my youth that JIF peanut butter doesnt work that much worse than normal thermal paste, but wears out faster...
I used to be REALLY into computer overclocking, god I miss my 200% OC's with my phase change unit getting my chip to -50C, maybe that'd work for wort cooling? lol
Anyway, you dont need anything fancy, and just use a thin layer.
Its meant to fill in the valleys created when you press the metal together to create more surface the heat can transfer through.
I used to put a a line on one end of my heatsink, and take a razor and spread it out thin, and be good to go. You can put a dab in the middle, and press the heatsink on your SSR and get the same results.
As another side note, I found in my youth that JIF peanut butter doesnt work that much worse than normal thermal paste, but wears out faster...
Bjornbrewer
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Agreed. just a thin layer and remember to not over-tighten the SSR to the heatsink! just snug is all you need...any more can adversely affect cooling (you start warping the bottom plate of the SSR). Also I'd avoid the razor...you could accidentally nick the metal and create a pit. just use your finger or popsicle stick.
haha!
Bret86944
Well-Known Member
The reason you use thermal paste is to create a thermal bridge between the two surfaces. On a microscopic level, the two surfaces only actually touch in a few spots, and there is an air gap over the rest of the area. Since air is a great insulator, there is a large resistance to heat transfer. Since you want the heat to move rapidly, you fill that gap with paste that easily transfers the heat. I'm sure you are wondering why I bothered giving you this useless knowledge. The answer is I don't really know...
Just to pile on here, too thick a layer will actually insulate your SSR, which ain't such a good idea. The paste doesn't have really good thermal conductivity, just a lot better than air. Thin layer, fill air gaps only, as said above, is good advice.
jjyoung
Well-Known Member
I "think" everyone's over thinking it a bit. 
No matter how much you put on, once you tighten down the bolts/screws on your SSR which attaches it to the heatsink the extra is going to squeeze out (ergo: use just enough, and not a bit more). Just don't put a lot on and make a mess. And be careful not to get any on any cloth you care about...you'll never get it out.
No matter how much you put on, once you tighten down the bolts/screws on your SSR which attaches it to the heatsink the extra is going to squeeze out (ergo: use just enough, and not a bit more). Just don't put a lot on and make a mess. And be careful not to get any on any cloth you care about...you'll never get it out.Similar threads
