Is Butyl Tape Still Recommended??

[Brezent]

Bought some butyl tape for rebedding and was planning to use till I talked to a yard manager the other day.

He claimed that butyl tape was not as good as 4000/4200 because it would heat up, ooze out, and loose it's seal. He indicated that it was all the rage a few years back, but didn't work as well as expected and recommended against using it.

Hoping to hear from people that used it 5+ years ago that can give feedback on how well it works over time. I expect that 4000/4200 will be good for 10 years.

[S/V Illusion]

Butyl was highly marketed by the folks selling it, not by those using it.

For those who don’t know how to properly use liquid sealants, butyl is idiot-proof.

For those who aren’t, use the proper sealant.

[Maine Sail]

Originally Posted by Brezent

Bought some butyl tape for rebedding and was planning to use till I talked to a yard manager the other day.

He claimed that butyl tape was not as good as 4000/4200 because it would heat up, ooze out, and loose it's seal. He indicated that it was all the rage a few years back, but didn't work as well as expected and recommended against using it.

Hoping to hear from people that used it 5+ years ago that can give feedback on how well it works over time. I expect that 4000/4200 will be good for 10 years.

It will do that if you buy an ordinary "butyl tape". Bed-It Tape is not a "buytl tape" but rather a hybrid formulation specifically formulated to limit cold flow/creep...

This article show you how to properly use it:
https://marinehowto.com/bed-it-tape/

[BenBowSirocco]

Many of the deck fittings on our old cutter were bedded in quality butyl tape 41 years ago and still dont leak a drop. Never oozed or caused issue for us. I have certainly seen some cheap stuff- especially on RV's that is oozy and works very poorly.



Compass Marine (marinehowto) sells some high quality tape- its awesome stuff.



Its especially helpful if you need to remove something with regularity- like a deck hatch in order to change the lens.



Be mindful of the bedding process, its not just stick it down and forget it, you need to re-tighten a couple times during its initial bedding.

[Dsanduril]

Barely at your 5 years, but we re-bedded our leaking stanchions with Bed-It Tape in 2016. No leaks so far (knock on wood). Have since used it for other bedding projects, less time on them, still no leaks.

One thing I appreciate is that it seems (so far) to last a long time, but when I do pull up a fitting that has been bedded in "butyl" (see Maine Sail's post as the reason for the quotes) it is easy to clean up/remove. My experience with 4xxx, 5xxx, other polyurethanes, silicones, etc. is that all of them are much harder to get rid of once used.

We followed the directions, which means we had some oozing/creep for the first week as we tightened things up. Trimmed the protruding bits at the end of that cycle and haven't had any noticeable ooze/creep since then.

Have used a no-name black butyl for sealing radio connectors and it does a good job there, but from experience it will get all over the place when used for anything else. There is a reason for specific formulations in specific use cases.

[valhalla360]

Used properly, it's perfectly fine and has some nice advantages in appropriate situations.

Used improperly, it's worthless and fails when used in inappropriate situations.

If it melts and flows out, you bought some faulty stuff.

It has almost no adhesive capability, so if you try to "glue" stuff together, you will be disappointed. It's best used where it will be under compression.

Example: Where the stays penetrate the deck, there are small plates that slip over and screw down. You caulk under them to keep water out. It's easy to form butyl to the space and when you screw it down, it squeezes out the side and you simply trim off the excess...works great and you can even remove and replace the plate if needed. If you go with 4200, when it eventually fails, it's a real pain to fully remove and if you screw down too far before it sets, you can't easily recover...it's grind it out and start over.

Stuff has been used for decades on RV roofs around hatches and I've never seen it melted out the side.

[pesarsten]

Used butyl tape from Mainsaill to Re-bed deck hardware 5 or 6 years ago. No leaks. Wonderful stuff, I used tape to mask around seal areas and removed after about a week of gradual tightening.

[DougR]

Used “bed it tape” on a large Bomar foredeck hatch about 4 years ago....still going strong.

Prior to that the hatch was bedded with 4200, and that lost its grip on the gel coat after 7 or 8 years.

[thinwater]

I started using butyl when I saw first hand the PERFECT job it did of sealing all the hatches on my 20-year old PDQ, and that it was still in perfect conditions when I removed them for reglazing.



It was not a decision based on fashion.


And as Mainesail said, there are many grades. Some are amazing and some are junk. That is the greatest challenge with butyl; getting the right product.



It has other limitations. I use it when:

• Large item that may need removed for service.
• Secured by bolts or substantial screws. No bonding required.
• Smaller items that are secured by through bolts but that may be prone to shifting under very high loads.

Yes, it does ooze out to some extent, but it can be trimmed and I have not found this to be a problem. Other sealants have other problems. It's not either/or, it's a continuum.

[Jammer]

There are experienced boatbuilders who still swear by the stuff and believe that 4200 etc tend to be overused by new boat owners. I use both.


Butyl is cheaper, has a longer shelf life, is less toxic, and is much easier to remove when the time comes compared to the polyurethane sealants. In applications where it will remain under compression it is a good choice. Even if properly applied, there will be some amount of cold flow so even if trimmed neatly it will tend to ooze out a little which looks messy if exposed.


Generally I use 4000UV polyurethane sealant to bed small deck penetrations above the waterline: stanchions, cleats, blocks, electrical cable. At or below the waterline I use 5200. For things like hinges and winch bases that can be securely tightened and that may have to be removed and reinstalled in the same place, I use butyl tape.

[Tetepare]

I swear by it, and it’s held up. Nothing rebedded has ever leaked.

It will ooze when squished. Cut off the excess and move on.

[roverhi]

The beauty of butyl is it can stretch as much as an inch without breaking the seal so especially good for hardware under torque loads that will break the seal of polyurethane and other tube sealants. I especially like it for lifeline stanchions which the poly and, god forbid, sillycone have special issues. Butyl is rubber so it will squeeze out to some extent but haven't had any significant flow after the initial compression of bolting parts on. I use the stuff from Mainesail and biggest complaint is peeling it off the backing tape. It also takes more time to apply butyl tape than squeezing goo out of a tube but is quicker to clean up with no chemicals required.

An anecdotal tribute to butyl. My 40 year old boat had a portllght that apparently had been leaking from the get go. Found evidence of three different sealants used to try and stem the flow. Sealed the port with butyl and it never leaked again.

[Paul L]

I used butyl tape supplied by a well known port manufacturer. In the tropics it has continued to ooze for 4 years.

[MarkSF]

Originally Posted by Maine Sail

It will do that if you buy an ordinary "butyl tape". Bed-It Tape is not a "buytl tape" but rather a hybrid formulation specifically formulated to limit cold flow/creep...

This article show you how to properly use it:
https://marinehowto.com/bed-it-tape/

I had trouble with "ordinary" butyl tape, so I bought the Bed-It tape, and I still have problems with it continuously oozing out when used in any application where there is significant flex, especially where it gets hot.

Mainly I'm thinking of stanchion bases. If you stress one of my stanchions, you can see water ooze out, meaning that the stuff has lost all adhesion with one of the surfaces.

Stanchions appear to need a fairly strongly adhesive sealant.

The Bed-it tape is OK for other applications, especially if you don't mind re-sealing every few years.

Back to liquid sealants mostly.

[Dsanduril]

That's the internet for you

Some of use are in complete agreement with your yard manager and some of us think it is approaching sliced bread. What do you want to hear? Whatever it is, you can hear it here.