How do you stop leaking skimmer box on above ground pool?

I have run into problems with plastic pool fittings leaking. In Australia there is a product known as selleys Aquakneedit. this stuff comes in a stick that has an outer layer that needs kneading together with the inner material of the stick. Clean the damaged area of the skimmer wit some wet and dry abrasive paper and then apply the putty to it. it has always worked well for me, up to now,