[OZ4]

Here's how I did it.

I repaired one like yours by using foil duct tape to form a mold to fill with two part epoxy.

I cleaned the edges of the case first so the epoxy will stick. Then held the foil mold in place with little clamps and more tape.

 I can't remember if the foil tape just released from the epoxy or if I used something to cause it to release. 

You might try testing some epoxy on the adhesive side first and see if it will release.

I never did get around to painting it.