would suggest Plasticweld epoxy putty. It's designed to work with most plastics, including PVC. Because it's a putty, it's moldable and can be used to attach to a greater amount of surface area of the pipe to the gun.
Explanation:
Main Plumbing Pipes. There are five plumbing pipe materials that are or were in the case of galvanized steel most common copper, galvanized steel, polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) and cross-linked polyethylene (PEX).
