Re: Repair of ABS plastic boat
I have a 1974 Apache camper. It is a hard sided pop up with ABS walls and roof. I have extensive knowledge of ABS repairs.

...Forget plastic welders, epoxys, glues, or anything that will shoot out of a caulk gun...The best way to fix it is to solvent weld the cracks using ABS/MEK goo. I buy ABS pellets from Apache Sales Corp, or if you can come up with a ABS source, you can cut it in small pieces. Anyway, take your ABS pellets/scraps and put them in a jar with MEK. The ABS will melt overnight into a goo. If it is too thick add a little more MEK. If it is too thin, leave the lid off the jar a bit and some MEk will evaporate. Next, put some MEK on a rag and rub your crack to soften the material. Paint the goo on with a 1" paint brush. Let it dry a few minutes and put on another coat, followed by another. It is best to put some fiberglass cloth in the middle of the coats. It will dry rock hard in a few hours. After a day or two, you need to paint the repair to protect it from UV rays.