Best choice for bedding deck fittings?

[peaman]

Today, I removed a deck hatch for the first time. I have read plenty about hatches that were hard to seal, or were impossible to remove for re-bedding, and as a result, I was dreading the need to re-bed a hatch.

But today, I decided to remove the forward hatch on my 1987 32-3 which was leaking in two spots. The removal was spectacularly easy, and the clean-up went pretty smoothly. It was way easier than I had imagined, and I like that. There were no traces of any prior re-bedding efforts, so maybe this was the first time since 1987 that the hatch had been removed?

Given the ease with which the hatch was removed and prepped for re-bedding, I would happily do the same every five years rather than to delay re-bedding only to have to use hammer and chisel or a halyard and purchase to pull a now-bent hatch frame, or to endlessly scrape at old rubber compounds.

So my question is, what's the best choice for bedding for a balance between good performance and ease of replacement? I've read here about some of the great qualities of butyl tape, but later removal apparently can be really tough. I'd like for the next removal for re-bedding to go as smoothly as the first.

 

[gabriel]

I didn’t like butyl tape because even in hot weather it wouldn’t fully compress and later it oozes out leaving whatever it was sealing loose. This problem seems exasperated on objects with large surface area and not so bad on single fittings where you can really crank down on the two surfaces and squeeze the stuff out. I also found out that it does in fact degrade.

That being said, I like 3M 4200 for this job.

 

[Loren Beach]

Given my recent experience re-bedding all of our deck fittings, including hatches, I would use Sikaflex 291,
and please refer to reply #10 in this thread-- https://ericsonyachts.org/ie/threads/sealant-for-rebedding.18651/#post-143857

Other sealants will certainly work, but this is our recent experience,

 

[racushman]

I've been using butyl tape for hatches and ports. I can see what some say about it continuing to squish out over a period of time, but that seems to stabilize after a couple weeks. What I like is you can use a lot of it... and be confident the seal is good... but it's easy to clean up... and easy to use when only one set of hands is available.

 

[Kenneth K]

This problem seems exasperated on objects with large surface area and not so bad on single fittings where you can really crank down on the two surfaces and squeeze the stuff out.

Very true. On small fittings (like the small cleat Mainesail uses in his butyl tape demo) butyl is quite simple. On my winch bases (where all the fasteners are around the perimeter, leaving a large, unclamped area in the center) it literally took months before the butyl stopped squeezing out.

On the flipside, it only took about 2 min to clean around the perimeter with a small pick and remove excess butyl each time I retightened. And, the final look was very clean. Based on this, I might say butyl is a drawback only if you're working with a large-based fitting that's in a hard-to-get-to area.

I used white butyl tape and I'm pretty happy with the results (though I'll probably re-tension again as soon as we get a few hot days).

 

[Lakesailor]

Sikaflex is a great product...3M also makes some good LPU adhesive/sealants. Cant go wrong with either of them and of course they come in different grades as well as clear/white/black. My personal preference is Sikaflex.

 

[peaman]

It was the following comment from Sharonov thay got me concerned about butyl:

"I used butyl tape. Several layers. Tighten screws over several days time. Remove squeeze where excessive amount got applied. No oozing after that. Maybe because the tape was from Maine Sail. As for adhesion, I had to remove the hatch later and had to use halyard and winch to pull it off."

 

[Martin King]

I like BoatLife Life Caulk. It's tensile strength is only 170 psi. That's a good thing when it comes to pulling stuff apart again. And you can get it in black, white, or teak colors.

 

[Parrothead]

I prefer sealants I've used in the past successfully, success measured in terms already mentioned:

• No leaks
• Ease in application
• Easy clean up with common solvents
• Flexibility
• No ooze
• Consideration for future gear removal
• Variety of colors, particularly white

In other words, I use the material I know. Below the waterline = 3M 4200 or Sikaflex 291, above the waterline = Boatlife Life Caulk, aluminum framed window refurbishment = Dow 795. I tried Butyl once in the 1970's from a caulk gun and once a few years ago in tape form on a friend's boat and detested both experiences. It failed over half of the properties on my list above.

 

[bigd14]

I am a fan of the butyl tape from Maine Sail's website. The stuff from RV and marine stores is garbage. I have been using it for portlights and deck fittings for 12 years and have never had a leak. The key is to use just enough for the job and no more, and if you apply when its cold use a heat gun to gently warm the fitting and deck before tightening it down. If you pile it on, it will ooze for awhile. It cleans up well with mineral spirits and is easily removable, although for larger surface areas it can be tenacious. Wedges, heat gun and patience work.

 

[c.gustafson]

I'll place another vote for Life Caulk. I've used Life Caulk on hatches and port lights with no problems.

 

[Loren Beach]

I'll place another vote for Life Caulk. I've used Life Caulk on hatches and port lights with no problems.

Just do not bed any plastics with it. The BoatLife company also makes "Life Seal" and that is the correct one for plastics.

 

[peaman]

aluminum framed window refurbishment = Dow 795.

What, exactly does this refer to? Fixed lights with aluminum frames? Or something else?
Thanks for your response above.

 

[Parrothead]

What, exactly does this refer to? Fixed lights with aluminum frames?

Yep, the fixed ports common in the 1970's. Many people find them challenging to redo/rebuild/reseal.

 

[Loren Beach]

Yep, the fixed ports common in the 1970's. Many people find them challenging to redo/rebuild/reseal.

Well stated. And "challenging" is such a nice polite word you can use around people with delicate sensibilities... !

 

[JSM]

Re bedded a leaking hatch four years ago with this. Still water tight.

DAP Dynaflex 230 10.1 oz. White Premium Elastomeric Exterior/Interior Window, Door and Trim Sealant 18275 - The Home Depot

DAP DYNAFLEX 230 100% waterproof window, door, siding and trim sealant is a premium elastomeric sealant with silicone like toughness to withstand the elements. Combines outstanding durability, adhesion

www.homedepot.com