It has been my experience as well, that epoxy resin will bond to sanded and cleaned plastic.
polyester resin will likely not work.
the 3m 5200 is great stuff, but i think you would have to prep the seat in the same manner as epoxy resin to adhere, and the 3m5200 takes, what 10 days to cure in warm climates?
In dog beers, I've only had one.
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Tilt your head, not the taco.