Anybody recommend a hot plastic weld tool.

[Harry Hill]

would pour foam in the bottom of your canoe make it better. I had a sears skiff that was made from some kind of plastic and at speed the bottom would pop in if you hit a wake or hard chop. I filled the bottom with pour foam and then took a grinder and made it flat and it worked great at stopping the flex in the bottom and never came loose and as far as I knew I never had a hole in the bottom so I don't know if it would stop a leak. It also made the bottom a lot warmer when fishing on ice cold lakes.Just an idea you might want to look into. You have to watch the density as the real dense stuff adds a lot of weight.