Caulk for rebedding bronze thru hulls

[cburger]

Opinions on compound for reinstalling bronze thru hulls. Was going to use buytl but supplier does dot reccomend for below waterline. Do not want to use 5200, something that stays plyable, maybe Dolphinite?

[HopCar]

Real men use 5200. Seriously this is exactly what 5200 was designed for. You are unlikely to need to remove a bronze thru-hull for the life of the boat.

If for some unlikely reason you do need to remove it, heat the bronze with a propane torch and the 5200 will let go. Easy peasy.

[JamesPNW]

Originally Posted by HopCar

Real men use 5200. Seriously this is exactly what 5200 was designed for. You are unlikely to need to remove a bronze thru-hull for the life of the boat.

If for some unlikely reason you do need to remove it, heat the bronze with a propane torch and the 5200 will let go. Easy peasy.

Yup. The 5200 is a pain in the butt to remove. I recently removed a window glued with 5200. It took 3 days to cut, saw, and chisel to get it out. The darn window wouldn’t move even just 1/2 inch glue left around the rim. It is a 15yrs+ old application. And that what you want for a thru-hull.

[Adelie]

When I redid the keelbolts for my Cal20 (real bolts thru a flange at top of keel) the supplier, who is the Cal20 guru, would not recommend anything but noted that they had originally been bedded in Dolphite and since I hadn’t been leaking after 49yr I decided to use that.

He also would not indicate how much to tighten the bolts and offered no hints. He was ducking liability and I thought that was smart of him.

I’ve also used Dolphinite to bed deck hardware.

[Allied39]

Yep, 5200 or, if you do not want to spend $30 go to home dopey and pickup a tube of Loctite marine sealer. It is polyurethane...the same as 5200, but it's about $14 a tube.
Great stuff, for below waterline and about the right price.

This was just answering the OP.s question, not interested in argueing or dealing with the trolls.

[mike d.]

Looney tunes are Great ! 5200 is an adhesive, not a sealant ! DO NOT USE 5200 FOR BEDDING THRU HULLS You should only use a poly sulfide sealant incase youi have to remove said fitting ! If you use 5200, you will have to do major damage to area to get said fitting out, unless you use their solvent, to degrade bond ! Like silicone, 5200 is not a bedding compound !!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Bycrick]

While 5200 is an adhesive rather than a sealant, the idea that it takes massive effort to remove a through hull fitting bedded with 5200 simply isn’t true. Last haul out, I replaced two through hulls, a 3/4” and a 1-1/2”. In both cases, the valve wasn’t easily removable from the inside due to space restrictions. The cost of the new through hulls was far less than the cost of trying to get the valves out to save 38-year-old hull fittings.

I took an angle grinder and cut two X-shaped cuts across the mushroom head. Warmed it slightly with a small propane torch and hit the pieces sideways with a hammer. They both came right out. Total time for both was less than 30 minutes, and I didn’t break a sweat.

[Orion Jim]

3M 4200 is perfect for underwater fittings.

[Manateeman]

The Locktite marine stuff looks like, sticks like, smells like, and seems to work perfectly ...like the high priced spread.
According to the manatees ...they can’t believe it’s not butter.
So they put it on popcorn and leave boxes of it labeled popcorn with white cheese. They put the boxes next to big power boats along with a six pack of beer then they just mosey around till the fun begins.
See...you thought Orcas were bent on revenge.
Happy trails to you.
Captain Mark and his prankster manatees

[DanielPerry]

Originally Posted by Orion Jim

3M 4200 is perfect for underwater fittings.

For what it's worth, 4200 will also cure underwater if applied to dry, clean surfaces. I'd personally use that or dolphinite.

[NYSail]

I use 4200 and make sure my mechanical seal is good.

Will never release

[Pegu Club]

We bed all of our Groco bronze thu hull fittings with 5200 during our refit five years ago, don’t fear 5200, removal is really no big deal, heat works well, and a product call ”unhesive” works as well. As was stated previously a real bronze thru-hull will last for far more years than you will likely own the boat.

Fair winds,

[skipmac]

I had to remove a few very old bronze thru hulls on my boat that PO installed with 5200. One came out, the rest even after heating with a torch until I was afraid of damaging the glass AND application of two different solvents that claimed to work on 5200 I had to cut out in little pieces.

[Locquatious]

Sikaflex 291 also works. It has the same flexibility as UV4000 and 4200. We had tried 5200 and pulled the gelcoat off when we did have to re-bed our bronze ports.

The copper in the bronze may inhibit the cure. We have seen uncured caulk in some inner regions of the seal. It may be that the outer skin formed during the cure prevented the inner caulk from curing.

Do not use wood on the interior of the thru hull. It will eventually rot and become spongy, such that you cannot tighten the compression bolts. If you must use wood, coat it with epoxy to slow water infiltration. A fiberglass ring works best.

[Seaturtle44]

I use BoatLife Life-Calk..
It cures to a positive waterproof seal below water line. Also can be easily removed.