Worried about Polysulfide

By: Grace L. Schmidt

QuestionI used polysulfide for my through-hull fittings, assuming it would be adequate for this application. However, I now read that it isn’t for plastics. Should I be concerned? I thought if a product didn’t have a vinegar smell it was fine for through-hulls.

AnswerPolysulfide is not compatible with polycarbonate plastics such as Lexan and Plexiglas. The polysulfide leaches the plasticizer out, and the product will become brittle, craze and crack. Most through-hull fittings, however, are not made from polycarbonate plastics. They are usually delron or nylon, which is fine with polysulfide. If the through-hull is polyethylene or polypropylene, you should be OK as well. Polysulfide is ideal for through-hull fittings, since the boat can be launched immediately after application.


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