RE: Source for ABS plastic?
If you need some ABS I have some .020,.030,and .040 in 12 x 18" sheets. $3 a sheet..
But i think the easiest way to fix your problem is to glass the inside with some fiber glass cloth. I would personally rough up the inside of the cowl with sand paper and then lay the cloth in place and use medium CA to adhere the cloth..It work great and fast too.....
Ty