By Don Casey
Revised by BoatUS editors in April 2012
What type sealant to use can be confusing. Here is the code:
- Use silicone to electrically insulate dissimilar metals and to bed plastic.
- Use polyurethane only to join components that will NEVER need to be disassembled.
- Use polysulfide for everything else.
There are exceptions, but following these three rules will avoid most wrong-choice problems.
Don Casey has been one of the most consulted experts on boat care and upgrades for 30 years, and a panelist on our "Ask The Experts" website for a decade. He and his wife cruise aboard their 30-footer part of the year in the eastern Caribbean. His books include Don Casey’s Complete Illustrated Sailboat Maintenance Manual, and the recently updated This Old Boat, the bible for do-it-yourself boaters.