Thermal Compound for PCs?

Hey guys. I'm also a PC enthusiast, and so, naturally, I have a surplus of thermal compound generally meant to increase heat transfer between chips and heatsinks. Has anyone tried using this for going between motors and heatsinks? I wonder if most PC thermal compounds would fail at the temperatures motors like Feigaos and whatnot run at.

[blueb8llz]

i use that between my 7xl and heatsink. i have not tried running it without the compound so i cant compare temps. but even with the compound, you still need to take breaks inbetween because the motor still runs pretty hot. the motor temp was around 186 after 15 mins of bashing. and it was like 60 degrees outside, and i have holes cut out on my body.

[BrianG]

As long as the two surfaces don't move (in relation to the other) while running, the surfaces mate quite well, and you don't use too much, it can't hurt. After all, CPUs can get to 60*F (granted, on the high side), which is 140*F.

[SunnyHouTX]

I will be putting some thermal paste on my LSP-R (my thread) tonight when I get home and will post before and after temp readings.

[blueb8llz]

for more accurate temps. you should run the truck both times with the same outside temperature. and on the same terrain. my guess would be with thermal paste...10 degrees less.

[brijar]

I have a heatsink on my Mamba Max 5700 motor in my Rustler and the heatsink always gets hotter than the motor, so I assume it is doing its job.

[pullinteef]

Originally Posted by brijar

I have a heatsink on my Mamba Max 5700 motor in my Rustler and the heatsink always gets hotter than the motor, so I assume it is doing its job.

How is that possible?

[VintageMA]

Originally Posted by pullinteef

How is that possible?

Well thermal paste is designed to increase the thermal transfer efficiency or a metal/metal contact so I suppose it could be possible.

I tried thermal paste on a motor heatsink, but I always had problems with keeping it from getting all over as I slid the heatsink onto the motor can. How have people gotten around this problem? Since most heatsinks are made of aluminum they are pretty rigid and don't bend well to just snap on over the can.

[Arct1k]

Originally Posted by brijar

I have a heatsink on my Mamba Max 5700 motor in my Rustler and the heatsink always gets hotter than the motor, so I assume it is doing its job.

Not really possible without a heatpump - Only suggestion is motor had cooled down and residual heat was in heatsink... This is difficult to imagine as the heatsink should be radiating more that the motor.

Only one final thought is that the heatsink was "radiating" more than the motor and fooling your temp gauage.

[SunnyHouTX]

Man, I guess RC-Monster makes a heatsink that's pretty snug! My little test was inconclusive: pretty much the same max temps all around.

Props to Mike, then! lol. I'll leave the thermal paste on my heatsink, since it's already there. Thanks Sunny.

[SunnyHouTX]

No probs man. I did notice that the motor cooled down quicker, a little bit.

[BrianG]

Originally Posted by Arct1k

Not really possible without a heatpump - Only suggestion is motor had cooled down and residual heat was in heatsink... This is difficult to imagine as the heatsink should be radiating more that the motor.

Only one final thought is that the heatsink was "radiating" more than the motor and fooling your temp gauage.

Or it could be the color and/or composition of the heatsink has a different emissivity rating than the motor. IR thermal probes are somewhat sensitive to that setting, which is why you are supposed to set the emissivity to whatever material/color you plan to use the most.

[Arct1k]

That's what my last statement was trying to say but not as techy/wrong i.e. radiating vs emissivity.

One final thought is IIRC AS5 is electrically conductive - AS ceramique i don't believe is...

This a really good question. I'm a bit of a nerd also, so when I did my E-Revo I slathered the RCM heat sync with cpu thermal paste. Didn't even think twice lol.

Anyway, I'm probably geared wrong as the esc and batts are getting barely warm, but the motor gets to about 70C after about 5 min of race style driving. The bottom part which is uncovered by the heat sync is much hotter than the actual heat sync itself.

The RCM sync is REALLY snug tho. I took it off after the first few runs to make sure there weren't any air bubbles and found that it was fine; I only put a very thin coat of paste on so was quite happy.

CPU paste isn't generally rated much above 60C tho, so I'd imagine that mine will be useless in another few runs; it'll all harden up and stop conducting the heat away from the motor. Might see if I can find some non cpu paste.