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butyl tape

34K views 53 replies 25 participants last post by  jarcher 
#1 ·
I am in the process of refitting the hinged lid of the propane locker that a PO had built into the cockpit seat. I want to seal the hinges to prevent water from getting into the screw holes (I have already overdrilled the holes, filled with epoxy and redrilled, but I still want to keep out unnecessary water).

I had seen butyl tape recommended for this purpose on a forum someplace, but I have not been able to find it on West Marine's or Jamestown Distributors' web sites.

Does anyone know where I can buy it? Does it have another name?

Or is there another product which is even better?
 
#3 · (Edited)
Not up here..

Ace, Lowe's and Home Depot do not carry butyl tape, at least in the North East, but they do sometimes carry butyl foam weather strip which is NOT the same as the rubbery silly putty like stuff. RV tape is also not the same quality as the good stuff the boat builders used.

Bed-It Butyl Tape

This is the stuff I use
:
 
#6 ·
Halekai, what's with the name change? Did you change vessels?
I've changed vessels three times since I owned Hale Kai but it took me this long to convince the admins to change my user name to Maine Sail, which is a non boat name just a screen name!

I use Maine Sail on most other forums except for a couple which are still "Acoustic", which was another boat name, prior to my current one. I have stopped using boat names due to my ability to buy and sell boats often!!;);););)
 
#10 ·
Hale, is there a material reason not to use the black butyl tape? or is is strictly aestethic? The reason I ask is that I have a nearly unlimited supply of black butyl tape that I can have at no cost; and being a cheap B@$~@r& ......... I would scrounge a small supply of it to squirrel away if it is simply a cosmetic difference.

Thanks, Fred
 
#12 ·
I got curious after Main Sail's earlier piece on butyl tape, so I got some from the online RV place and used it when rebedding locker hinges. Impressively sticky stuff.

Considering that it seems to stay sticky for a very long time--I think MS showed something that had remained pliable and sticky for over a decade?--and seems easier to work with than a caulk gun full of Sikaflex, I'd like know what its limitations are, if any. Is butyl tape suitable for all above-waterline hardware rebedding jobs? Say for stanchions, clutches, etc?
 
#13 ·
I got curious after Main Sail's earlier piece on butyl tape, so I got some from the online RV place and used it when rebedding locker hinges. Impressively sticky stuff.

Considering that it seems to stay sticky for a very long time--I think MS showed something that had remained pliable and sticky for over a decade?--and seems easier to work with than a caulk gun full of Sikaflex, I'd like know what its limitations are, if any. Is butyl tape suitable for all above-waterline hardware rebedding jobs? Say for stanchions, clutches, etc?
I've used it on every type of mechanically fastened devices that you can think of and it works great.

Limitations include feathering a joint and smoothing over the bead. I can't think of any use on deck where I would not use it. As i said 80% of my boat has yet to need re-bedding. My genny tracks for example were done at the factory with butyl nearly 30 years ago and they are still bone dry with not even one drip..
 
#15 ·
Actually, most of the hardware stores DO carry butyl tape just not where you might think it is. Look for a 3-6' long roll, 1-2" wide, in the PLUMBING section or the ELECTRICAL section. I've bought 3M's prime quality "butyl self vulcanizing tape" in Home Depot, right next to the other 3M electrical tapes, it is used to waterproof cable and antenna splices. These tend to harden up over time, not rock hard but layers fuse. Regular butyl "caulking" tape will stay gummier longer.

Sometimes they stock clear silicone tape--which is pretty much the same product, doesn't quite self-fuse as permanently but can be used as a gasket material just as well. Sold in the plumbing sections (along with butyl) as a hose/pipe leak patch material, too.

I'm assuming the tape is going to be laid down flat as a gasket under the hinge panel--not stuffed in the screwhole. Either of these should work as a gasket material, without needing to buy a huge roll from a special place.
 
#16 · (Edited)
I have both self vulcanizing tape and glazing quality butyl ribbon or flat tape sitting in my shop. They are NOT the same product!!!!!!!! I would never even consider using the self vulcanizing tape over the glazing grade butyl.

The stuff I use is very, very, very gooey and sticky and comes stuck between waxed paper as it can not go onto a tape roll or it will be destroyed trying to un-roll it. There are a few grades of things called butyl but self vulcanizing tape IMHO is not one I'd choose for re-bedding deck hardware.

Perhaps in some parts of the country you can find butyl glazing tape in home centers and hardware sotres but not here. RV stores are the only places I've seen the flat version in colors like gray and off white. Again, I would NOT suggest using black if it can be avoided. I used black on my port lights but only because I could not find a source in the diameter needed in gray or white..

Black Round Butyl Tape:

Keeping the black off the gelcoat:

As you can see I used 3M 101 polysulfide to seal the trim ring to the exterior and the butyl to seal the port to the cabin. This kept the black butyl off the gelcoat..
 
#17 ·
A lot of 'better' junk yards, window companies, and windsheild installers carry the black butyl tape, the window places, and steel siding companies often carry the grey or white variety.
I've picked up the black butyl by asking a windsheild installer who was working in the parking lot, gave him $6 for two rolls, don't know if it was a good or bad price, but we were both happy with the transaction so it wasvalue for value.

Ken
 
#18 ·
The stuff I got from the RV supply link Maine Sail provided last time is like very sticky putty in a strip--can be molded to itself just by rolling it between your fingers. It's 3/4" wide and maybe .1 inches thick. I'm planning on using it as my surface "gasket" material and around screw heads and in the deck screw hole countersink. Overall, I like the gray color--it blends in with metal amd looks OK where it shows against the white gelcoat. And you can sort of cut it with a plastic blade to trim after it oozes.
 
#19 ·
When working with the butyl tape, leave the paper backing on, for as long as you can. That will aid you in getting the same thickness over all.
 
#22 · (Edited)
Here's why I like butyl tape

This is a cut-a-way photo i made of a section of deck that I first potted with epoxy then countersunk. I then wrapped butyl tape around the bolt head, tightened it down and left it there for a while. I then loosened the bolt and began pushing up from the bottom. There is no movement on a boat, with a mechanically fastened deck fitting, that will even come close to that amount of flex and stress on a sealant.

Remember this stuff has very low adhesive properties, unlike 5200, 4200 or any other caulk tube type sealant, and cleans up quite easily with paint thinner. Adhesion is not necessarily needed flexibility is! This stuff will out stretch and out flex any caulk tube sealant you can buy in a marine store..

Of course you must always bevel or countersink the deck side so you can fit more sealant in the gap. The more sealant the more allowable flex. If you look close you can see the beveled edge.

Yes I finally got sick of trying to describe the process of potting holes and countersinking so I took some pictures.

Stretch!


 
#23 ·
Maine Sail-

Nice photo... :) very illustrative of the properties of butyl sealant. Glass shops usually carry it btw... but usually only in the black. :(
 
#26 ·
Butyl tape and visqueen beats tarps and tape for staying dry

We are currently living on a boat with all portlights and one hatch removed. Replacing them is taking longer than expected. Meanwhile, we've had sleet, snow, rainstorms, and temperatures in the 20's.

We are snug and dry, thanks to butyl tape and visqueen plastic.

Here's what we did: We cut a piece of plastic to fit over each opening. We formed a long skinny "snake" of butyl and put it around the perimeter of the plastic, then stuck it on. It's quick to put on and take off (we use a dull razor blade to get it started), so we can put it on at night and take it off while we're working. Unlike tape, it doesn't leave residue and we just keep using the same piece over and over.

This would work for just about any large opening or deck repair.

For small holes, just make a ball of butyl and stick it over the hole.

The only downside to this solution is that when you have hail, it's like living in a large, noisy drum! But it holds up just fine.
 
#27 ·
I'll be re-bedding my bow pulpit soon and I have a question on the application of the butyl tape. Obviously it goes around the bolts as per Maine Sail's instructions.
But would you also cover the entire bottom of the plate base with strips of it? I don't see why this would be needed if the bolt holes are sealed with it. Your thoughts..
 
#28 ·
Yes

Yes I cover the entire base of the fitting then tighten it down. It's best to wait for a hot day and the butyl will compress easier.. The problem with us NE boaters is that water can get under a fitting and expand and yuo don't want that so it's best to seal the entire base. Get the thin flat butyl tape. I think mine is 1/16" thick if I am not mistaken.
 
#31 ·
Yes I cover the entire base of the fitting then tighten it down. It's best to wait for a hot day and the butyl will compress easier.. The problem with us NE boaters is that water can get under a fitting and expand and yuo don't want that so it's best to seal the entire base. Get the thin flat butyl tape. I think mine is 1/16" thick if I am not mistaken.
I concur completely. I am on Lake Ontario, so while we don't have the salt, our freeze/thaw cycles are as brutal as Maine's if not worse (we are enjoying one today, for instance!).

I got hit at dock by a Peterson 37, the crew of which had loosened the nut on the wheel in preparation for a winter haulout...BEFORE they had motored there...anyway, one of my stern quarter extrusions had been bashed and needed to be removed for rewelding and anodizing. So when I got my wife back in the stern with a rachet and undid the afflicted piece, I noticed it was fully bedded in grey butyl tape.

My boat was 33 years old at the time, and this stuff was "live" in the sense of being seemingly fresh!

Not being one to argue with success, when I redid the job, I redid the butyl tape the exact same way, but with separately bedded and new bolts and fender washers. It looks great and there will always be a place aboard my boats for this half-forgotten but very versatile product.
 
#29 ·
Thanks Maine Sail. My tape is about the same. About 1/2" wide and 1/8" thick, gray. I can heat the surface and SS with a heat lamp before I pull everything tight with the bolts. I bed my topside teak hand rails last year and still had some squeeze out the joint during the summer. Easy to remove.
 
#30 ·
I think the butyl I have is more like 1/8". I'd love it if it was 1/16" as half of it squeezes out--but at least at that point you can be pretty sure you've got a great seal there.

A couple of things about butyl I've found lately:

* When working on an overhead bolt that hangs straight down, a dot of butyl on a washer will hold it there temporarily while you are trying to get that nut on there.
* Mineral spirits gets it off your fingers and other surfaces if necessary. This is especially handy when your fingers have reached critical mass of stickiness, turning you into spider man.
 
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