According to the datasheet, the dissipation at 40 amps will be around 27 watts.
In actual riding, you probably won't be running at 40 most of the time, so dissipation will be less.
Imaging stuffing a 25W light bulb into a little box and letting it run for a while. It's going to get pretty hot. Any amount of air circulation around the fins will help tremendously.
The heat sinks look very good. Potting in epoxy sounds good. Make sure to test it before pouring the epoxy!
In actual riding, you probably won't be running at 40 most of the time, so dissipation will be less.
Imaging stuffing a 25W light bulb into a little box and letting it run for a while. It's going to get pretty hot. Any amount of air circulation around the fins will help tremendously.
The heat sinks look very good. Potting in epoxy sounds good. Make sure to test it before pouring the epoxy!