I have this heat sink laying around
and thought maybe I can use it to mount my focboxes on to get a better cooling.
My question is now, could I just screw the focboxes with there stock heat sink on my heat sink like this
and wouldn’t it support the cooling?
Or do I need to dismount the pcbs and mount them directly on my heatsink with a thermal pad inbetween?
I know @Kug3lis is a heatsink expert 
maybe you can give me some advice.
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I would get some heat transfer paste/tape and mount them as is directly to the heat sink. Then cut as small a hole as you can in your enclosure and bolt it to the enclosure, with the fins down. Once you have the fit perfec, remove it from the enclosure, add some 3m silicone (or other sealant) and re-mount it.
Any idea where you got that heat sink? Looks nice.
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I got the sink in our local electronic store for about 5$ 
I‘ll mount the heat sink on top of my battery on top of my deck into a custom made 3D case.
So that shouldn’t be an issue.
Just on the focbox I have this terminal on the place of the fets
As my heat sink is flat, I would need to creat some kind of spacer plus use bigger thermal tape. If no, I think I would short the other contacts from the pcb.
That’s why I came to the idea if it’s possible to use the heat sink of the focbox as it’s already everything cut out right for the pcb and just add some more heat sink on top of it.
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You could buy some plastic stand offs and then you could mount straight to the big heatsink. Unless you’re just want to slap it together as is. Either way will work. I would say though, mounting the pcb to the bigger one would be better though.
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But for this i would need a 5mm thermal pad
Not sure where I can get something like that
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More heat sink the better surely. Do like mike. Get the fins in the airflow.
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I dont know if that pad will be thin enough to do its job well? 
The regular pad is thin as heck
Yeah my bad forgot what it actually looked like. So what about cutting the heat sink out of the focbox bottom and then attaching? Same concept as you were thinking. I figure with it just being the heatsink part instead of the whole bottom, your causing a more direct path to the bigger one. I hope you followed that lol. Cloud 9 as usual here lol
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I don’t think it will crest enough heat to worry about that. Unless he just ovst amps it down/up hill
put the stock sink back on the focboxes and bolt the big sink directly to the stock sinks. You can do this because there are threaded screw holes ready to be used on the focbox sinks. I’d get some Arctic Silver or other CPU thermal past to smear on the surfaces before bolting together just to make sure they are thermally coupled.
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That’s all I did. made a plate and mounted the focboxes to it with some thermal paste. Then mounted the plate to the deck. Does the trick. Nothing fancy.
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@akhlut and @longhairedboy thx for confirmation. That was the intial plan. Just add some thermal paste between the sinks and than bolt it together through the holes which already in the stock sink. Just wanted to get it confirmed that it will work like this.
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is heat sinking them necessary? I have been running 45A per VESC in my eboosted enclosure without it for a while. I do live in the UK mind, we are not famous for our hot weather 
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Nu i need a bit more than 45a for my 8085 motors
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Same and I’m in qld where winter only gets down to a chilly 25 degreesC Not a heat issue with standard sinks running 40amp per
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No, 45a should work with the stock sink too. With the boosted sink it will work even better I think.
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Ask @Kug3lis how much amps he pull through his focboxes
It’s a bit more than 50.
Everything just depends how good you can get rid of the heat.
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fair enough mate, good to know… I am just about to start a Trampa build with a pair of focbox so handy to know this
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