I'm getting close to mounting hatch rims (one Valley oval, one Kajaksport round) on fiberglass/epoxy lips I've fabricated for my Isfjord. I'll also be installing new hatch rims on my NDK Explorer, as both hatch rims have cracked through next to the mounting rivets (Kajaksport tells me this happens when the factory either improperly countersinks or overtightens the rivets). In any event, I've been wondering what sort of adhesive/caulking to use.

I've looked at some of the Sikaflex and Lifecaulk products available in the local marina, but they all caution not to be used on plastic surfaces, and the rims are ABS plastic.

I emailed Kajaksport (and got a response within 24 hours....still waiting to hear from NDK after two weeks). They suggested I prime the plastic surface with Sika Primer (215 or 290DC), then use Sikaflex-221 caulk to bond the rim to the deck. But the primer alone is around $60 for a small quantity and that seems steep.

Does anyone know of another product compatible with ABS plastic? A friend suggested priming the mating surface of the ABS rim with epoxy to protect it, then using Lifecaulk. Another suggested 3M 5200, but I've heard that makes subsequent removal for repair near impossible.

Any suggestions?