Connecting polypropylene to straight pipe (without inside bevel)
Polypropylene to copper drain with male thread

You should use a rubber 1 1/2&quot; slip-joint gasket for this connection.


Polypropylene to Oatey Sure-Vent

What you have should work fine, as long as the tapered edge of the slip-joint washer fits into the ID of the fitting (as opposed to butting up against it...)