Best adhesive or sealant for plastic through-hull fittings?

[rhafley]

I'm replacing my livewell intake, drain, and overflow fittings. I have some Boatlife Life Caulk but I was thinking about using 4200 or 5200. What say the experts here?

[McGreavster]

5200. The fast cure one is thicker and won’t drip and make a mess. Also it cures in 1-2 days vs normal that doesn’t fully cure for closer to 7.

[RazorCat]

I used the 5200 slow cure on my last thru hull fitting repair. It’s activated and cured using water. I would hit it with a spray bottle twice a day to keep it moist. McGreavster is right about cure time although mine was solid in about 5 days in 80degree weather, but I waited 7 days to put the boat in the water. The fast cure 5200 will work, but you don’t have much time to work with it before it starts setting. Permanently. At least in my experience. Hence, the reason I used the slow cure.

[SkeeterSD]

3M 5200. But it’s a real pain in the ass to get off after it dries.

[ClarkBird]

A "Below the water line" silicone is better and much easier to remove when the time comes.

[Mike D.]

Life caulk !!!!!!!!! If you use 5200 and you damage, or an other reason need to take out the through hull fitting you will destroy the fitting and probably damage the hull ! 3M 5200, 4200, 4000 are all polyurethane adhesives, first and formost! Their sealing capability is secondary! Silicone can be used, but it is not a true bedding compound for this purpose !

[Marshfly]

4200 or Lifecaulk is the right thing to use if above the waterline. There are VERY few instances where 5200 is the right adhesive. I just can't understand why it got this reputation as the go-to adhesive for most things on boats. Totally unnecessary and way overkill for the vast majority of applications.

[McGreavster]

4200 or Lifecaulk is the right thing to use if above the waterline. There are VERY few instances where 5200 is the right adhesive. I just can't understand why it got this reputation as the go-to adhesive for most things on boats. Totally unnecessary and way overkill for the vast majority of applications.

Never seen a livewell intake above the waterline. I don’t think there’s anything wrong with using 4200 or 5200 below the waterline. But if you’re resealing something under the waterline what’s wrong with opting for the more permanent adhesive? It’s not like you’re pulling off thu hulls every season to reseal lol, do it right once and you’ll be good for a very long time. And it’s not like 5200 is completely unremovable and 4200 cleans up with no elbow grease, you’re going to have to work to clean up both old ahesives.