What sealant do I use to seal exhaust tips and the fastener holes?

What sealant do I use to seal external steering brackets and fastener holes?

What sealant do I use to seal tie down U bolts and holes?

What sealant do I use to seal thru hull fittings (above the water line)?

Appreciate the time, Fellas!

I use 3m 4200 on all those parts. DO NOT use 5200 unless you never want to remove it.... ever! I look at 5200 as window urethane .... Better than a weld.

I recommend against using anything labled bath tub caulk you find in the mark down bin at the dollar store.

I liked to use 3m 101 Marine Sealant (polysulfide) on items I may want to remove, but I guess it was discontinued by 3M. Another polysulfide sealant similar to 101 is BoatLife Life Caulk. I like 4200 too, but find the polysulfide's are a little easier to work with and also easier to remove later.

3m 4200 is a good choice for everything you listed.

+1...4200 if below the water line..it also helps if you install the part loose the mask around the area with masking tape..when you add the sealer then tighten up the part and the sealer ooozs out you peal the tape off and it takes the sealer with it for a easier clean up..

"3M 4200 Fast Cure is a one-part general purpose polyurethane sealant with good adhesion to wood, fiberglass, gelcoat, plastic, and metal. When cured, 4200 forms watertight, weather-resistant seals on joints and boat hardware above or below the waterline.


4200 FC (fast cure) is ideal for hardware and bedding applications. It is paintable and sandable. While 3M 5200 sealant results in permanent bonds, 4200 has approximately half the strength, making it a good choice for applications where the bond may need to be broken in the future such as replacing hardware."