Originally Posted by
TravisW
RTV won't hold very long, if at all. HDPE is a very waxy plastic that until recent advances in epoxy technology could only be fixed with plastic welding, and even now the special epoxy is pretty pricey, so plastic welding is still the cheapest method of repair. Harbor Freight has a couple different plastic welders, one for $40 without an on-board air motor (you have to hook it up to an air compressor), or one for $60 with its own air motor, both capable of reaching high enough temperatures to weld HDPE. You'll have to look elsewhere for HDPE welding rods since I haven't been able to find them there, supposedly zip-ties make good welding stock.