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Recommendations for Adhesives & sealants for boating.

First time post guy here. I'm normally a dry land 5th wheel RV-er, which has its own types of caulks and sealers, (butyl tapes, lap sealants) But I just bought a 40-year old Bayliner Nisqually, and I'm wondering about the types of marine sealant goo I should use, and where.

For example, I just unscrewed a strip of decorative teak from the side of the cabin -- behind it and across the top there was a copious glob of what looked like clear silicone rubber sealant, which seemed to have work quite well, but sure ugly.

Can someone give me a novice rundown of standard marine sealants, and where the might be used?

Example, 3M 5100 for underwater thru-hull tasks -- type of sealant behind rub rails or railing posts, or cleats, held down by screws.

Thanks, kids.
Brad on Whidbey Island.
 
For example, I just unscrewed a strip of decorative teak from the side of the cabin -- behind it and across the top there was a copious glob of what looked like clear silicone rubber sealant, which seemed to have work quite well, but sure ugly.

Ayuh,.... Welcome Aboard,.... that was most likely the handy work of a P/Owner,....

Sillyseal is rarely used on/ in boats,...

5200 is for anything you will never try to remove again,.....
4200 is for things ya know will someday need to be taken apart,....

I never use never-seize, but always use Permatex #3, which is the same stuff as Quicksilver Perfect Seal,.....
 
For 'above the waterline' applications, your previous experience is highly applicable....bondo provided the preferred below the waterline sealer....


The only other item I'd add that may come in handy is epoxy.....again, depends upon what you are doing...
 
Silicone is used by people who have never had to remove it ten years later.
Not surprising but the same caulk you use on your house works on a boat. Dap Alex plus is my go-to. Takes paint, cleans up with water, sticks to everything and lasts for years. If you have to remove it it is soft enough that it comes off pretty easy. I rarely use 5200 except for places below the waterline for permanent install. Thing is once you take the cap off, that's it. Begins to catalyze and after a week or two you have a solid lump inside the tube. I buy the little tubes but even then I throw away more than I ever use.
For things that might be removed, I like to use dum dum. Also known as rope caulk. Usually found in with the weatherstripping. you put this between the deck and what you're bolting, and then tighten the fasteners. It's non hardening, so years later if you want to remove that thing it will come away clean. I put this around the stainless thru hull fittings for the bilge pump outlet. Works great.
There are bazillions of dedicated products, but the best are the simplest/cheapest. In the old days the only thing they used was white lead and linseed oil mixed to peanut butter consistency. This was known as bedding compound and got slapped on everything. Sorta like window glazing putty, if you know what that is.
 
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