Before taking apart the esc, test the esc on the bench. This insures that the esc is working before you dismantle it and  lose the warranty.

This is the picture of the fets with the heat sink removed. We used a conformal spray epoxy to make the board more water "resistant". Spraying 5 coats.

This is the bottom of the board. We also sprayed 5 coats of spray epoxy on this side. You will see some red on the circuit board! By mistake I picked up red spray paint and started to spray the circuit board.

Removing the heat sink is simple. 4 screws behind the sticker hold it on. When taking off the plate beware, its also held on with thermal tape. Slowly lift starting at one edge. I cut out a 65mm x 42mm brass plate from some 1mm  thick stock. Round & removing any sharpness on the edges.

I cut a couple of pieces of 5/32 K&S tubing to 75mm long. Soldering them on proved a bit difficult. Because the plate is so large, it takes lots of heat to solder the tubes to the plate. I used two soldering irons at the same time. One iron directly on the center of the tube that was on the edge of the plate. Than used another to apply the solder to the entire length of the tube.

I'm going to continue to use the stock heat sink. It will help hold he new cooling plate and I hope provide even more cooling. 

Added double sided kapton tape to the bottom of the new brass plate. This will help conduct the heat from the fets to the new plate.

Completed unit. After allowing the unit to dry for 6 hours or so, I powered it up on the bench and its working great. My only problem will now be finding a boat to run it in for a real life test..