Here is a pic of our pipe exiting the plastic barrel. The union goes
through the barrel. It is held by a flange of epoxy that extends
maybe 3/4" out past the fitting. We worked the expoy into the cavity
from both sides, hard. The inside has some JB Weld dripped over it as
well. Not needed, I think, but helpful. This joint is about 10 years
old. We thought the rigid epoxy filling the space would do the job.
It did. The joint does not have much motion. Smaller pipe brings the
water into the barrel. It is set in a similar manner. Basically, we
have formed epoxy in and around the barrel to hold it still.
Others may have good ideas about other methods for holding the seal.
Jim