Is it OK to use plain (tub and tile type) silicone to bed cleats, etc to the deck or should I use 3M 4200?
Thanks,
Frank
Thanks,
Frank
Bedding cleats and blocks to the deck
- Thread starter ffaubert
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... try butyl sealant
Definitely 4200 is better than silicone for bedding deck hardware, but butyl tape is even better. It stays pliable and lasts for years. Read MaineSail's excellent post on butyl.
You folks are awesome! On my way to pick up some butyl tape from the local RV centre.
MaineSail, if you read this, thanks for a fantastic tutorial. Everybody else, thanks for pointing a newbie in the right direction.
Frank
MaineSail, if you read this, thanks for a fantastic tutorial. Everybody else, thanks for pointing a newbie in the right direction.
Frank
I am going to rebuild my winches, which may require that I remove one or more entirely [hopefully not]. If I do have to rebed, I looked on ebay as suggested and it seems there is more than one variety of butyl tape. There was something for metal, then something for porous materials, and one that claimed "high strength bonding". The latter would not seem desirable for what I am doing because one would want the option of removal down the road if necessary. Are there really several formulations, or is this the same product being marketed in several different ways?
Butyl tape is really the sealant of choice for any deck hardware that is:
A) Through bolted
B) Not exposed to fuel or liable to be exposed to fuel on a regular basis. Butyl tape dissolves in gasoline or diesel.
A) Through bolted
B) Not exposed to fuel or liable to be exposed to fuel on a regular basis. Butyl tape dissolves in gasoline or diesel.
Sailingdog; I need to install a couple of eyestraps on my deck. The flat area that rests against the surface is very small; maybe 1/2" in diameter w/ a 3/16 hole in the center for the fastener. Does the tape work well for that small footprint?
For a first-rate job, avoid silicone or butyl tape. How many times do you want to do the job over in the next 5 years? Neither of these forms a proper bond; both must be kept under constant and pretty intense pressure to keep from admitting water. Something like 4200/5200 forms an actual chemical bond (adheres more-or-less permanently to both surfaces) and requires only a modest about of pressure to remain watertight. In fact it cures better when you don't apply too much pressure. Silicone never cures completely at all-- you'd be better off with a plain rubber gasket.
Ask yourself this-- would you bed through-hulls and the keel to the hull with butyl tape or silicone? No; because it would leak. Why allow leaks above the deck too?
Ask yourself this-- would you bed through-hulls and the keel to the hull with butyl tape or silicone? No; because it would leak. Why allow leaks above the deck too?
I doin't think that there's disagreement that silicone is not the best choice for deck-mounted hardware (though it's better than nothing). I'm curious about your rejection of butyl. I was fairly impressed with Mainesail's report on butyl sealant, and I've used it this year when refastening some deck hardware. It's my guess that since butyl adheres well but does not cure hard, it would remain attached and therefore waterproof even if the hardware moves slightly, whereas any sealant that cures hard will ultimately fracture under constant mechanical motion (thermal cycling, etc).
Do you have information to share about how butyl tape might fail earlier in this application?
I agree that butyl isn't suitable for below-waterline application, but thru-hulls generally don't experience the same mechanical abuse that deck hardware does. I do like 5200 for below-the-waterline use.
I used 4200 as a caulk along the top edge of a teak rubrail, and after 3 six-month seasons, and then covered for the winter, the 4200 dried up, went chalky, and cracked. I've seen cheap acrylic caulk last outdoors longer than that...
If you want to use caulking I suggest that you use Life Caulk. It has served me well for many years. Personally I have never had a failure which is the reason I continue to use it.
I also happen to be a beliver in butyl so it is also an excellent choice.
I also happen to be a beliver in butyl so it is also an excellent choice.
I am in 100% agreement about silicone, with the exception of bedding acrylic lenses or certain plastic items. I'm sorry to say though that you're misinformed about butyl tape and the fact that mechanically fastened deck hardware needs to be glued to the boat at 300-700 PSI. Builders don't use butyl for deck hardware anymore because it is more labor intensive than a drum of Devils glue. Butyl, when used appropriately, is an excellent and considerably longer lasting sealant in terms of flexibility and rejection to age degradation. Unlike a PU it does not continually get harder and dry out as I have witnessed on numerous occasions with PU sealants. The consistency at 30 years will be basically the same as when installed. Considering the hundreds of thousands of boats out there with wet decks that were originally bedded with 5200 or another PU sealant, and the hundreds of leaking pieces of 5200'd or other PU sealed deck hardware I have personally re-bedded, including the entire deck of a 2005 Catalina 310, in 2006, I can assure you that 5200 AKA Devils Glue and other PU sealants are not the panacea many make it out to be including the marketing departments. Oh, and I can't forget to mention the keel reset I had to do when the 5200 failed to do it's job. Or the leaking hull/deck joint on another boat that were all failures of polyurethane sealants.
Of course no sealant will last long if not installed correctly. I am still amazed that soooo many builders refuse to take the extra 30 seconds to bevel/countersink the deck penetrations. Probably the number one reason I had so many deck leaks on a brand new Catalina, no beveled holes. Though amazingly CS did not bevel, and used butyl, yet virtually nothing has leaked in 31 years.
When I do not use butyl, and I don't for everything, my next choice is a polysulfide then a low bonding polyutethane such as Sika 295UV or Sikaflex 291 or 291-LOT. Butyl is not for every application, for instance I would not use it around fuel fills, and while it certainly could be used to seal a thru-hull I prefer products that are specifically rated for such, insurance wise. Butyl tape is often used in underwater wire runs across the ocean floor to seal connections, and from what I have heard, with very high reliability. Still I reserve it for above water applications..
Concession about butyl
Kenn, I may concede that butyl keeps water out. That said, because it remains flexible forever does indicate it does not lend strength. You may rely on the bolts to hold the mooring cleat down; but bear in mind that 5200 (and even 4200) would be stronger. After all, viewed from an engineering point of view, you'll realize the bolts don't hold your lead keel on; the 5200 does.
I do not find working with 4200/5200 very awkward at all. In fact a freshly-epoxy-treated piece of mahogany or plywood is a very good surface for 5200 to bond to, and I have redone nearly all of my interior bulkheads and done my new exterior wood with this combination. All my bulkheads are bonded to the hull with 5200 and epoxy/cloth. In this application, butyl might dampen vibration between a piece of plywood and the hull because of taking up space, leading you to believe it was solidly attached, but I would not expect it to lend stiffness and integrity of strength (i.e., what is known as 'egg-crating') to the hull structure. In fact this is a case where its very flexibility would be a drawback. 5200, while flexible, is limited in its flexibility just enough to yield as much as it should and stay stiff enough to be strong. That's what it's made to do.
The other issue is compression loads. My uncle Joe used butyl tape between hull and deck on the early Raider 33s. The problem was they all leaked, because from just usual use the toerail-deck-hull bolts would work loose owing to the tape's flexibility. It simply never 'cured' like an epoxy or 5200 would. So a maintenance issue was imposed requiring that the bolts be consistently tightened, ad infinitum. With that kind of torque applied to the bolts, eventually the butyl tape was squashed to a microscopic thinness... and the boat would still leak. (The in-the-field fix? Smear a bead of 5200 along the inside seam. Hmmm.)
5200, by contrast, is excellent in all 3 common loads: shear, tension, and compression. It is simple to use, cleans off your hands with Fast Orange, is easily manipulated into weird crevices, and holds like sin. I restored a Robin dinghy on which, doing it myself, I could not reach to put nuts and washers on the foredeck cleat and the towing/trailer eye. They're on there with 5200 alone. It's a small boat (300 lbs), but those fittings with NO backing nuts, just 2 square inches of 5200, will support its full weight.
I can respect a 25- or 30-year longevity of butyl tape, though I maintain that it's not being subjected to 5200-type loads or it would probably have given over. And I'll state that I've NEVER, in nearly 40 years in this business, seen properly-applied 5200 fail. (In fact the one thing that made up my mind about buying the boat I do have is that the then-33-year-old 5200 under the aluminum toerail didn't-- and still doesn't-- leak. At all.)
Thanks for hearing me out. I'll stick to the devil I know, since I know its merits intrinsically.
Kenn, I may concede that butyl keeps water out. That said, because it remains flexible forever does indicate it does not lend strength. You may rely on the bolts to hold the mooring cleat down; but bear in mind that 5200 (and even 4200) would be stronger. After all, viewed from an engineering point of view, you'll realize the bolts don't hold your lead keel on; the 5200 does.
I do not find working with 4200/5200 very awkward at all. In fact a freshly-epoxy-treated piece of mahogany or plywood is a very good surface for 5200 to bond to, and I have redone nearly all of my interior bulkheads and done my new exterior wood with this combination. All my bulkheads are bonded to the hull with 5200 and epoxy/cloth. In this application, butyl might dampen vibration between a piece of plywood and the hull because of taking up space, leading you to believe it was solidly attached, but I would not expect it to lend stiffness and integrity of strength (i.e., what is known as 'egg-crating') to the hull structure. In fact this is a case where its very flexibility would be a drawback. 5200, while flexible, is limited in its flexibility just enough to yield as much as it should and stay stiff enough to be strong. That's what it's made to do.
The other issue is compression loads. My uncle Joe used butyl tape between hull and deck on the early Raider 33s. The problem was they all leaked, because from just usual use the toerail-deck-hull bolts would work loose owing to the tape's flexibility. It simply never 'cured' like an epoxy or 5200 would. So a maintenance issue was imposed requiring that the bolts be consistently tightened, ad infinitum. With that kind of torque applied to the bolts, eventually the butyl tape was squashed to a microscopic thinness... and the boat would still leak. (The in-the-field fix? Smear a bead of 5200 along the inside seam. Hmmm.)
5200, by contrast, is excellent in all 3 common loads: shear, tension, and compression. It is simple to use, cleans off your hands with Fast Orange, is easily manipulated into weird crevices, and holds like sin. I restored a Robin dinghy on which, doing it myself, I could not reach to put nuts and washers on the foredeck cleat and the towing/trailer eye. They're on there with 5200 alone. It's a small boat (300 lbs), but those fittings with NO backing nuts, just 2 square inches of 5200, will support its full weight.
I can respect a 25- or 30-year longevity of butyl tape, though I maintain that it's not being subjected to 5200-type loads or it would probably have given over. And I'll state that I've NEVER, in nearly 40 years in this business, seen properly-applied 5200 fail. (In fact the one thing that made up my mind about buying the boat I do have is that the then-33-year-old 5200 under the aluminum toerail didn't-- and still doesn't-- leak. At all.)
Thanks for hearing me out. I'll stick to the devil I know, since I know its merits intrinsically.
Hi DianaOfBurlington,
Thanks for expanding on your comments. I agree with everything you've said about 5200, especially about its strength and other virtues as an adhesive.
(I've been using WD-40 to clean my sticky fingers, but I will give Fast Orange a try)
Where we might disagree is in regard to the mounting of deck hardware, which I believe was the requirement in the original question. In this application, all the strength is expected to come from the hardware, and so what's required is a sealant, and bonding strength is less important and sometimes a negative, if the hardware might be removed later, or where motion, torque or thermal cycling might cause the adhesive bond to fail. Example, think of the forces on a stanchion base - no adhesive is going to survive those. It's all on the hardware, and the sealant needs to remain intact.
For mounting deck hardware, I believe that's the top requirement.
Thanks for expanding on your comments. I agree with everything you've said about 5200, especially about its strength and other virtues as an adhesive.
(I've been using WD-40 to clean my sticky fingers, but I will give Fast Orange a try)
Where we might disagree is in regard to the mounting of deck hardware, which I believe was the requirement in the original question. In this application, all the strength is expected to come from the hardware, and so what's required is a sealant, and bonding strength is less important and sometimes a negative, if the hardware might be removed later, or where motion, torque or thermal cycling might cause the adhesive bond to fail. Example, think of the forces on a stanchion base - no adhesive is going to survive those. It's all on the hardware, and the sealant needs to remain intact.
...bingo
For mounting deck hardware, I believe that's the top requirement.Hi,
Well, I used the butyl and that stuff is great. Less than $10 for a fifty foot roll 1" x 1/8".
This is the boat's first year with me and by the looks of it the PO removed all the deck fittings to paint and didn't bother to re-bed them afterwards. I say this because I found out last night that the fast acting lever cleats for the main and jib halyards was on backwards. When I removed it to turn it around, the paint was different than the two coats that are bleeding through now (different story, maybe a new thread when I go to repaint it this fall). There was nothing under the cleat assembly. When I went to countersink the holes as per MaineSail, I found the core is somewhat rotten (new project).
Anyhow, the butyl will get me through the summer and in the fall I can find and repair all the rotten spots, repaint the hull and topsides, revitalize the non skid areas and re-bed all the deck fittings.
Prepare for lots of questions that my copy of Don Casey's Sailboat Maintenance Manual may not answer.
A different Frank
Well, I used the butyl and that stuff is great. Less than $10 for a fifty foot roll 1" x 1/8".
This is the boat's first year with me and by the looks of it the PO removed all the deck fittings to paint and didn't bother to re-bed them afterwards. I say this because I found out last night that the fast acting lever cleats for the main and jib halyards was on backwards. When I removed it to turn it around, the paint was different than the two coats that are bleeding through now (different story, maybe a new thread when I go to repaint it this fall). There was nothing under the cleat assembly. When I went to countersink the holes as per MaineSail, I found the core is somewhat rotten (new project).
Anyhow, the butyl will get me through the summer and in the fall I can find and repair all the rotten spots, repaint the hull and topsides, revitalize the non skid areas and re-bed all the deck fittings.
Prepare for lots of questions that my copy of Don Casey's Sailboat Maintenance Manual may not answer.
A different Frank
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