leak at connection to drain pipes and Holding tank

Years ago,I broke off the dump valve when it caught on a tree stump.It also cracked the connection where the drain line came out of the tank. I used JB Weld apoxy. I cleaned off the crack in the tank and mixed and applied the JB weld per the instructions. It lasted for the over 2 years and then I sold the trailer.I have used JB Weld on different things both plastic and metal and it always worked for me.