SBH wrote:

Anyone have a suggestion for a good plastic glue/adhesive? I need it to be
very strong.

As you know, there's no such thing as one glue that works well on most
plastics, and super glue usually isn't so super for them, except maybe
Bakelite and polyester.

Plastics like styrene, ABS, PVC, CPVC, acrylic (plexiglass/Lucite),
and maybe even polycarbonate can be dissolved together with a solvent,
like acetone or lacquer thinner, but you really should use something
made especially for the particular plastic, especially acrylic and
CPVC (CPVC glue can be used on PVC, ABS, and styrene).

Plastics not affected by acetone or lacquer thinner, like nylon,
delrin, polypropylene, and polyethylene usually have to be melted
together with a soldering iron or wood burning iron (the Teflon tip
helps), but hard plastics, like Bakelite and polyester, can usually be
super glued or epoxied well. I don't know about 2-part acrylic glue
(not related to acrylic solvent), except that you don't want to stock
up on it because it spoils in just a few months. You may want to
check the websites of companies like Tech Bond, Tap Plastics, and N-
bond.