Waterproof Case for ESC

thingiverse

I've got several EMAX SimonSeries 12A ESCs that I'm planning to use in a small RC watercraft and I'm looking for some advice on waterproofing the ESC. As you know, airborne or waterborne systems are notoriously susceptible to water damage, and most solutions focus on embedding the ESC in heatshrink or conformal coating. However, these methods don't offer any way to dissipate heat, so I needed to find a different solution. I already had the ESCs, but then I stumbled upon 22mm x 22mm x 10mm anodized aluminum heatshrinks on Amazon (Gadgeteer 10pcs Aluminum Heatsink, $8.99 for 10). The 3D printed parts were created using a Makerbot 2X printer with PETG filament. Next, I removed the factory heatshrink from the ESC and attached the aluminum heatsink to the surfaces of the ICs using double-sided thermal transfer tape that came with the heatsinks. Then, I fitted the heatsink/ESC assembly into the 3D printed case, making sure the heatsink fins protruded through a hole. To seal the gap around the heatsink (and wire feed throughs) and the case, I used epoxy. The cover was then fitted with a piece of foam wedged internally between the back of the board and the cover, and the seam was sealed with epoxy as well. I've only bench-tested the waterproofed ESC so far, and at full load, the fins of the heatsink barely get warm. However, I still need to install it in an aircraft, which will be a small seaplane. We'll see how it works off the lake this summer.