[George Da Porge]

I've read through Mainesail's primer on bedding gear with butyl. Am convinced that's a great way to go for many applications. One nice thing is that it seals right away since it has no cure time. But it is recommended to tighten the fasteners over a several day (or longer) period. Keeping that in mind, can butyl rubber be used in applications where the fasteners doesn't penetrate the hull or deck? For example, on our Catalina 30 some cabin-top hardware (deck organizers, winches, etc.) is anchored by nuts embedded in the core. If you tighten these bolts over a number of days won't the seal between the BR and the bolt be broken?

 

[Minnewaska]

The chamfer that needs to be cut away from the deck top, should hold the butyl, even if the fitting presses it all out against the deck. When I rebed some stanchions, I had to cut a chamfer. Not much of one, mind you.

 

[elvishessler]

I do not believe Maine ever recommends tightening a screw or bolt more than once.

 

[DonScribner]

Have you used this stuff before. I'm sure there are different grades for different applications but the stuff that the PO used to seal our portlights to the cabin just dripped out over a period of years. It is non-curring and will seek to equalize surface pressure. So, if it seals to a surface, then you move that surface slightly, it will find it and seal to it again.

My company uses butyl tape extensively for one of our commercial product lines. Part of the installation process is to retighten the screws for that very reason.

 

[MarkSF]

If you tighten these bolts over a number of days won't the seal between the BR and the bolt be broken?

No. Because the butyl tape doesn't really set, it can tolerate being re-tightened.

What would be the difference between tightening to a given torque in one step, or two steps, as far as the sealant is concerned? A setting sealant would set during the delay between first step and second, and tear, ruining the seal. That's not going to happen with a non-setting sealant.

 

[pdqaltair]

The hatches on my PDQ were bedded in butyl, mounted with self-tapping screws.
* Never retightened.
* No leaks 1997-2015.
* Easily removed after 18 years.

I'm sure it all depends on the product. I use it all the time.

However, in general I will use 4200 or 5200 for small screw mounted hardware, depending on the size (very small surface contact gets 5200, larger contact 4200 or butyl). For single screws in particular (like small pad eyes and snap screws), a dab of 5200 keeps them tight and still removes easily. A lot of 5200 contact area is a whole 'nuther nightmare.

 

[hellosailor]

Butyl sealant (including tape) may never "cure" and that also means it creeps, forever. So you snug down on it, give it a chance to creep a bit, and if you want snug down some more. Just be aware that if you do keep snugging it down, it will keep creeping out from the pressure, so there's a limit to how useful it is to keep tightening down on it.

 

[Maine Sail]

Butyl sealant (including tape) may never "cure" and that also means it creeps, forever. So you snug down on it, give it a chance to creep a bit, and if you want snug down some more. Just be aware that if you do keep snugging it down, it will keep creeping out from the pressure, so there's a limit to how useful it is to keep tightening down on it.

Sorry but this is just incorrect......

 

[hellosailor]

I've spoken to guys with 30+ year old C&C's that had butyl tape as the caulking between hull and deck. They said it still crept, and that it could still often be tightened to stop hull/deck leaks.

Which is both a pro and a con, versus a permanent structural adhesive like 5200.

So what part is incorrect? Butyl tape stops creeping? Can't be squeezed out or cut by overtightening? In what time frame?

Like plumber's putty on a sink drain basin, butyl is GREAT when you need to remove and reseat something. Assuming you will.

 

[George Da Porge]

If you tighten these bolts over a number of days won't the seal between the BR and the bolt be broken?

No. Because the butyl tape doesn't really set, it can tolerate being re-tightened.

I wasn't clear in my statement. The nuts for these bolts are embedded in the cabin top (no access to them). Any tightening must be done by turning the bolt. So, will turning the bolt compromise the seal between the butyl and the bolt?

 

[hellosailor]

With butyl tape, the bolt is just compressing the tape between two surfaces (i.e. a winch base and the deck) and the bolt itself is never being sealed by the butyl, it is just acting like a flat o-ring that was placed around it.

 

[Minnewaska]

The proper method is to have a chamfer at the deck, which takes up some sealant. Compression between two flat surfaces is not really the point.

 

[RichH]

Butyl sealant (including tape) may never "cure" and that also means it creeps, forever. So you snug down on it, give it a chance to creep a bit, and if you want snug down some more. Just be aware that if you do keep snugging it down, it will keep creeping out from the pressure, so there's a limit to how useful it is to keep tightening down on it.

Ive stopped using Butyl tape on components that can possibly 'move' or 'deflect' - stancheon bases, chainplate through decks, etc. Butyl Rubber does remain 'soft' (remains 'viscous') thus is able to continue to creep. Traditional caulks do cure and over time become an elastic (rebound) that more easily can 'follow' any such deflection.

I still use Butyl tape; but, Im damn careful to totally tighten the components together so that there is a strong mechanical/frictional connection between the solid surfaces/faces, etc. ... assuming that the only advantage characteristic of the Butyl is that will it will more easily 'fill' any irregularity between the non-moving faces of the components Im attempting to 'seal'.

Im having better luck simply using filled elastic (GFlex) epoxy to set my stanchion bases and chainplate through-decks. When in future if I need to remove - wire cable saw, fine toothed FeinTool cabinet blade and/or impact chisel. Ive also raised all the stanchion bases with 1" high FRG 'pedestals' to keep them higher than the flush deck, etc.; pedestals epoxied and gel-coated to the deck. I'll be experimenting with raised 'moats' for the chainplate trough decks. The only place I'll use butyl is non-stressed components such as port lights, etc.
Currently Im putting 10+nMi on my boat per year and my decks get 'water loaded' often, and the Butyl-taped deck components that are repetitively stress affected are just not standing up and sealing against all that 'rigor'. Ive had more time consuming and expensive water leak damage from using Butyl tape than I ever had when using polysulfide, etc. caulks - enough !!!!!!!

 

[Minnewaska]

The point of Butyl on a stanchion base is that is remains stuck to the base and the deck, even during some flexing. Dried adhesives don't. Using epoxy makes no sense to me.

You do require a small chamfer to hold some butyl around the bolt at the deck.

 

[MarkSF]

Ive stopped using Butyl tape on components that can possibly 'move' or 'deflect' - stancheon bases, chainplate through decks, etc. Butyl Rubber does remain 'soft' (remains 'viscous') thus is able to continue to creep. Traditional caulks do cure and over time become an elastic (rebound) that more easily can 'follow' any such deflection.

I still use Butyl tape; but, Im damn careful to totally tighten the components together so that there is a strong mechanical/frictional connection between the solid surfaces/faces, etc. ... assuming that the only advantage characteristic of the Butyl is that will it will more easily 'fill' any irregularity between the non-moving faces of the components Im attempting to 'seal'.

Im having better luck simply using filled elastic (GFlex) epoxy to set my stanchion bases and chainplate through-decks. When in future if I need to remove - wire cable saw, fine toothed FeinTool cabinet blade and/or impact chisel. Ive also raised all the stanchion bases with 1" high FRG 'pedestals' to keep them higher than the flush deck, etc.; pedestals epoxied and gel-coated to the deck. I'll be experimenting with raised 'moats' for the chainplate trough decks. The only place I'll use butyl is non-stressed components such as port lights, etc.
Currently Im putting 10+nMi on my boat per year and my decks get 'water loaded' often, and the Butyl-taped deck components that are repetitively stress affected are just not standing up and sealing against all that 'rigor'. Ive had more time consuming and expensive water leak damage from using Butyl tape than I ever had when using polysulfide, etc. caulks - enough !!!!!!!

10 miles a year? Gosh.

 

[RichH]

ooooops 10K+ nMi/yr