Resealing above waterline thru hulls

[boatrboy]

I am resealing the 2 1/2” exhaust thru hull and a smaller 5/8” for a sink drain.

One of my posts about resealing cockpit hatch hinges, it was suggested to use Buytl tape for the hinge and bolts as it’s a great all purpose sealer above the waterline.

I believe Lazy Daze and Techmitch commented on the many uses for this tape, So my question here is, does Buytl tape make sense here too? I realize it’s non hardening and wonder if that is a negative here.

I’ve read many posts about sealing these and most end up in a debate 5200 vs 4200.

 

[Golfman25]

I would probably go with 4200 on those.

 

[bobeast]

Given those choices, 4200. 5200 only if you want to insure no-one will ever be able to remove them. Given that there is a backing nut, I'd even go with just clear silicon.

 

[Lazy Daze]

Because this is a mechanical connection, it's really just about "sealing", not "glueing". Meaning, you don't need anything "adhesive". You can get away with just about anything here. But, yes, butyl tape would work very well here. If you don't have it - don't worry about going out and buying it, though. A good caulk/sealant is MORE than adequate.

Place the fitting temporarily in the hole and mask the hull around the fitting. Then apply the sealant and install the fitting.

 

[my3sons]

^^^^
After I painted the cleaned up hole with unthickened west systems epoxy and it was allowed to dry.

 

[sbw1]

4200 is made for this type of fitting.

 

[Skybolt]

42/5200 is also perfect, I don't find much difference between the two. But use mineral spirits for clean up and it will come out perfect. I am not a big fan of butyl tape although many are. I find the sticky 42/5200 is perfect.

 

[sbw1]

42/5200 is also perfect, I don't find much difference between the two. But use mineral spirits for clean up and it will come out perfect. I am not a big fan of butyl tape although many are. I find the sticky 42/5200 is perfect.

5200 is for below the waterline applications. These fittings are above and will need to be replaced eventually. Using 5200 on them will mean pulling off a lot of gel coat getting them out. 4200 is a sealant made for this type of fitting and is removable with out damage.

 

[Skybolt]

5200 is for below the waterline applications. These fittings are above and will need to be replaced eventually. Using 5200 on them will mean pulling off a lot of gel coat getting them out. 4200 is a sealant made for this type of fitting and is removable with out damage.

I use 5200 for everything and there is no way in hell it will pull gelcoat off. 5200 although advertised as a adhesive, is a much better sealant and the only way I have ever used it. a little heat and mineral spirits and it comes right off, have done this many times.

 

[Soulshine]

I use 5200 for everything and there is no way in hell it will pull gelcoat off. 5200 although advertised as a adhesive, is a much better sealant and the only way I have ever used it. a little heat and mineral spirits and it comes right off, have done this many times.

I so glad you said that. I'm tired of the mythogy that 5200 is this impossible to remove stuff that can do all this damage.

Applied to new work where everything is clean and fresh, it's tenacious for sure but anything that is assembled can be disassembled with some patience and ingenuity.

Heat helps too.

 

[Lazy Daze]

I guess we're getting a little off track here but, "technically" 5200 adheres to gelcoat with greater strength than gelcoat does to fiberglass. Yes, heat can work to soften it up. And, for sure, if someone likes using it - go for it. That's why we have options But in reality, it's WAY overkill for a mechanical connection (both in strength/tenacity and price). Other products are better suited for this application - and they will "seal" just as well.

4200 and 5200 are both approved for below the waterline - 5200 is just stronger. 4200 is still quite strong as an adhesive, though.

We all have our opinions (including me) and what we like/don't like. For me... truthfully, I almost NEVER use 5200. I save that for things that meant to never come apart like a deck to hull joint. I'd rather use a sealant for a job like this - again, it will SEAL just as good - and make disassembly even easier down the road. I realize saving some money here isn't the primary issue - but I also hate just throwing it away for no reason.

So... my opinion... if I had it laying around (which I usually do), I would go to butyl tape first. Next would be one of the Boat Life products - like Life Seal.

If anyone hasn't ever used butyl rubber tape - check into it. It is generally considered the #1 sealing product for cases like this where there are two flat surfaces and ultimately held in place mechanically. It will seal 100% and you can even take it apart 10 years later just as easy as it would be 10 minutes after applying.

 

[Skybolt]

I guess we're getting a little off track here but, "technically" 5200 adheres to gelcoat with greater strength than gelcoat does to fiberglass. Yes, heat can work to soften it up. And, for sure, if someone likes using it - go for it. That's why we have options But in reality, it's WAY overkill for a mechanical connection (both in strength/tenacity and price). Other products are better suited for this application - and they will "seal" just as well.

4200 and 5200 are both approved for below the waterline - 5200 is just stronger. 4200 is still quite strong as an adhesive, though.

We all have our opinions (including me) and what we like/don't like. For me... truthfully, I almost NEVER use 5200. I save that for things that meant to never come apart like a deck to hull joint. I'd rather use a sealant for a job like this - again, it will SEAL just as good - and make disassembly even easier down the road. I realize saving some money here isn't the primary issue - but I also hate just throwing it away for no reason.

So... my opinion... if I had it laying around (which I usually do), I would go to butyl tape first. Next would be one of the Boat Life products - like Life Seal.

If anyone hasn't ever used butyl rubber tape - check into it. It is generally considered the #1 sealing product for cases like this where there are two flat surfaces and ultimately held in place mechanically. It will seal 100% and you can even take it apart 10 years later just as easy as it would be 10 minutes after applying.

I get what your trying to say Dennis but I have been working with this stuff since it came out and personally I would not use it as an adhesive. It is the best sealant I have ever used. As an adhesive it will hold most things but I would never rely solely on that. Removal after it's been on for a few years is quite easy with some heat and a putty knife. If your going to try and hit with a hammer or try and push it through something from the un-sealed side, then good luck, not happening. But when tackled right, no problem.

I just (this past fall) re-attached my salon window to the hull with 5200, cleaned and prep'ed correctly. I noticed later that the window itself had cracked (plexi) and was leaking and needed to be replaced. It took some doing, but some 45 minutes later and the window frame was out. Like I said, heat, mineral spirits and putty knife.

 

[Lazy Daze]

I get what your trying to say Dennis but I have been working with this stuff since it came out and personally I would not use it as an adhesive. It is the best sealant I have ever used. As an adhesive it will hold most things but I would never rely solely on that. Removal after it's been on for a few years is quite easy with some heat and a putty knife. If your going to try and hit with a hammer or try and push it through something from the un-sealed side, then good luck, not happening. But when tackled right, no problem.

I just (this past fall) re-attached my salon window to the hull with 5200, cleaned and prep'ed correctly. I noticed later that the window itself had cracked (plexi) and was leaking and needed to be replaced. It took some doing, but some 45 minutes later and the window frame was out. Like I said, heat, mineral spirits and putty knife.

Sure, understood, Orlando. Different strokes for different folks. All good!

 

[boatrboy]

Wow - quite a variety of opinions and experiences here.

Funny I was trying to avoid the 5200 vs 4200 debate and found myself on the 3m website. They recommend 4000 UV for thru hulls.
It’s interesting that all the other sealers don’t even mention thru hulls.

I posted this originally because I bought a roll of Buytl tape a month ago for the hatch hinges and am sitting on it as that project is not done yet. It just seems like a good option and much less messy.

You guys have me reading and learning more from all of your personal experiences.

 

[Lazy Daze]

It interesting that all the other sealers don’t even mention thru hulls.

Most thru-hulls are one of the easiest things to seal. They've got a big, wide flange and are entirely held in place mechanically - some even have a depression to allow for extra sealant.