Bedding bolts with butyl tape

[zoidberg]

It is recommended to use butyl tape around through-deck fasteners to seal againstwater ingress. One is encouraged to chamfer the holes themselves to prevent water ingress so that the butyl material is squeezed into the small cavity thus formed.
A YouTube video shows small O-rings made from butyl tape which are mounted onto the shafts of bolts, which seems to require rather a lot of fiddly work cutting them out.

Why not simply use rubber O-rings, which are cheap and ready-made?

 

[RunAgroundHard]

O rings could work but a rough chamfer seal is more tolerant to butyle than an o ring. It is not hard rolling butyle like blutak then fashioning a seal in a hole.

 

[sarabande]

Rubber degrades, butyl stays sticky (well the good quality stuff does).

Perhaps trial a strip of butyl wrapped round a bolt stem rather like PTFE tape, then tighten the bolt. It will amalgamate into a homogenous seal, conforming to any imperfections in the bolt hole. Trim any excess to prevent butyl getting in the sipes of your shoes and speading over the deck.

 

[peteK]

It is recommended to use butyl tape around through-deck fasteners to seal againstwater ingress. One is encouraged to chamfer the holes themselves to prevent water ingress so that the butyl material is squeezed into the small cavity thus formed.
A YouTube video shows small O-rings made from butyl tape which are mounted onto the shafts of bolts, which seems to require rather a lot of fiddly work cutting them out.

Why not simply use rubber O-rings, which are cheap and ready-made?

I think you are thinking of neoprene tape,butyl tape can be mouded like plasticine around bolts etc.

 

[Rappey]

I fitted a wood 3" rubbing strake to a boat. Used a 50mm buytl strip behind the wood . Clamped it up. Wasnt right so unclamped.
Was amazed at how well the butyl was stuck and it was a bit of a fight to pull the wood back off. I love butyl tape !

 

[rotrax]

For bolts and screws I just roll it out into 1-2mm 'snakes' and wind it around the threads.

Never failed yet. I bedded 6 portlights and four windows to the 4mm steel cutouts of a steel yacht after making good the corrosion damage caused by the builder fixing them inside. This, of course, left a 4mm lip to corrode as sea and freshwater could collect in the recess.

After having 4 new larger windows made and re-affixing the old portlights and the new windows to the outside, sealing both windows and screws with black butyl tape, the interior was as dry as a Nun's crutch.......................................

I had to do a lot of 'butyl tape snake making as there were in excess of 400 3/16 inch UNC screws! Plus the washers and nuts!

Took a while.

 

[PabloPicasso]

Above the waterline butyl tape is the way to go.

Can even be reused!! Imagine having to undo and rebed something in an isolated anchorage on your summer cruise. Its great stuff.

 

[Dellquay13]

I’ve found the Scapa brand butyl foam tape to be wonderful stuff, as long as you get at least 30% compression all around.
The only time it hasn’t worked for me was on a pulpit base which was bent and warped, and didn’t compress the tape evenly.
Even then, getting the failed tape off to use a gun sealant was wonderfully easy.

As with any sealant, countersinking your holes through grp helps prevent stress cracks and beds the sealant in better

 

[pmagowan]

Stuff works well, relatively cheap, keeps good, easy to apply, easy to reuse and remove. Not fiddly in real life.

 

[GHA]

Bedding Deck Hardware With Bed-IT Tape - Marine How To

 

[jane444blue]

Bedding Deck Hardware With Bed-IT Tape - Marine How To

But where to buy this in the UK? Is US the only option

 

[ChromeDome]

Commonly used in the roofing industry. I recently replaced a plastic sheet roof and had these supplied with the net metal sheets (black in my case, to suit the roof colour)



but available in several variants


When torqued down the butyl "washer" will be squeezed to a perfect seal.

 

[stuartwineberg]

+1 for butyl. I bought a few metres of butyl glazing tape from eBay, works a great and a lot less messy than the stuff in a sealant gun (eg arbormast)

 

[peteK]

I used it to seal a slight leak on a fresh water tank on the pipe connection which was on the bottom of the tank,it was a polyethelene tank so not much else would stick to it.Wrapped the tape around the joint and then covered it with self amalgamating tape.

 

[Ammonite]

It is recommended to use butyl tape around through-deck fasteners to seal againstwater ingress. One is encouraged to chamfer the holes themselves to prevent water ingress so that the butyl material is squeezed into the small cavity thus formed.
A YouTube video shows small O-rings made from butyl tape which are mounted onto the shafts of bolts, which seems to require rather a lot of fiddly work cutting them out.

Why not simply use rubber O-rings, which are cheap and ready-made?

A lot of the late 1990s Moodys use O rings to secure the chain plate to the deck, or at least the fitting that holds the stem balls which in turn is tied to the hull. In theory it's a nice idea but in practice it's a lousy solution and most seem to have been fitted with O rings, traditional caulking and copious amounts of sealant in and effort to stop them leaking...and that was from the factory. If you can guarantee a flat surface and holes that line up perfectly with the machine screws or studs in the fitting I'm sure O rings would work but on a boat....whereas if you countersink the holes and wrap butyl tape around the underside of the studs it takes up the gap and seals perfectly.

 

[alahol2]

But where to buy this in the UK? Is US the only option

Search for Arboseal GZ tape. It has the same properties as the Bed-it tape recommended.
I can vouch for the fact that this tape works fine. There are many other butyl tapes available but I've never tried them...