3M Marine Grade Silicone or Butyl Tape

[capt. meares]

I am refinishing the wood rails on my 22 cruiser. I am trying to decide which is the better option when mounting them back. All input and advice is appreciated. Thanks

[colobear]

I'm not sure, my rails are stainless, but I think your cabin rails are through bolted into the cabin roof since they would be designed to take a lot of force and are safety features. I'd check inside the cabin for evidence one way or the other. I would not use silicone at all. If I just wanted to adhere the rails rather than through bolt, I'd use either 5200 or 4200.

[Sunbeam]

Not silicone, in my opinion. Why? First of all, it doesn't make a good, long-lasting bedding compound. Worse (much worse), it will leave a residue you will basically never be able to remove, and which will greatly hamper ever painting, re-bedding, etc. The contamination is miserable to deal with.

I generally liked to use a bedding compound such as Dolfinite (with some sealant on the wood such as varnish so that the wood won't just dry out the compound by soaking it up). It's been a while since I had any teak to bed though! Now I would definitely consider butyl.

Something easily removable/clean-uppable is good because it's a job that will need to be done again (you'll probably want to refinish the rails again if nothing else). Silicone doesn't fall into this category.

[AstoriaDave]

Concur with Sunbeam. Silicone is a huge PITA because of the residue. Dolfinite if you imagine you will pull the rails to refinish them sometime in the future. 4200 if not. 5200 is overkill for rails, I feel.

[Lost Petrel]

I recently rebedded everything on one of my sailboats with butyl tape and never will go back to anything in a tube again if at all possible. The ease of use and lack of mess alone is worth it, but it is a proven longlasting method.

Whatever, I also would stay away from any silicone.

[doubles]

Recently completed same rail project on my 22 and used butyl when remounting. Much better solution IMHO. Just take a few days and cinch down daily for best results. Clean, effective and long lasting

[Molly Brown]

My vote is for butyl tape and here is why......

http://www.pbase.com/mainecruising/rebedding_hardware&page=1

[Sunbeam]

I should mention that I use good quality butyl for most bedding now. I may have made it sound like I would only just barely consider trying it, or was lukewarm on it - not at all! In fact use it for anything where it isn't contraindicated.

Mainly I detest silicone (so that was my emphasis). Although I probably would use a bedding compound and not an adhesive polyurethane or the like, simply because I wouldn't feel the adhesive property was necessary and it makes life a bit more difficult when the time comes to re-bed/re-finish the rails (but nothing like the agony of silicone). I'm pretty spoiled by the ease of re-bedding with things like Dolfinite, butyl, and polysulfide.

There are times when I use adhesive polyurethanes or polyether though, so it's not like I have anything against them.

[thataway]

My problem with butyl tape is that you have to have it in compression. It has little if any adhesive property. If fittings loosen, then you can have a leak. This is where there have been a number of failures in RV's where the butyl is used because of the ease of application. (and less cost factor).

I realize it has achieved popularity in boats recently--I feel that there are better compounds.

I prefer 4000, because of the UV resistance. It has a cohesive factor with teak and fiberglass which is about the same in peel strength tests.

[Sunbeam]

Absolutely, it is mostly a bedding compound, not an adhesive. My rails are all through bolted, so no adhesive is needed - but every situation is different.

I have not had one single failure/leak (yet) (knock on something!) on two boats, an RV, and a camper trailer (all fiberglass). I've bedded quite a few things (mostly aluminum/stainless/fiberglass, with a bit of plastic for variety). What I did find out is that 99.99% of the "butyl" sold at camper stores is inferior - truly horrible. I had five ancient rolls from work, and you could stretch them out to like five FEET without them breaking. When those ran out I bought rolls from a number of sources and they all broke with about a 4" stretch, if that. Horrible. I started buying it from Maine Sail (the pbase link above) and the rolls I get from him are just like the "good old" rolls I had at work. Stretch till the cows come home. And I like the ease of removal/re-doing when the time comes.

I experimented on some Starboard (in a spot where a leak would not be disaster) and so far it has gripped that tenaciously (surprised even me!?).

Everyone has their favorites though - and lots of things work well, especially with good prep. Just no silicone

[nordicstallion]

I, myself would not trust anything short of thru-bolts for a handrail. If you need them, you will want them bombproof ! Maybe this is due to my rock climbing years. Bombproof redundancy was the key to longevity. I use the same logic offshore. But that's just me. Vern

[thataway]

Vern, I believe that all of the handrails in the C Dorys are bolted. But there may be some which are not. Many of the SS railings, have a nut welded into the void, or a bolt thru the teak, with a bung on the top. If they are screwed, then they should be thru bolted.

[capt. meares]

Thank you all for the input. I know it is a debatable topic, I just needed a little help making my mind up. I should add that the rails were originally mounted with screws up though the inside, into the wood. I also forgot to mention that they had silicon when I removed them. I do not know if the silicon was original from the factory but was still holding a good seal, with zero signs of moisture on any of the screws. I have decided to go with butyl. I think it will work fine for something that will not be receiving any stress. From what I have gathered, a small bevel in the fiberglass will compress the butyl well when squeezing it down. Worse thing that could happen is it may leak and I will try something else.

[Sea Wolf]

The Teak caabin handrails on my 1987 Cruiser are held on with long lag-screws, and have never leaked after being taken off and refinished with 7 or more coats of clear polyurethane.

Don't remember what I used for a sealer, but it works (!). (It's hell getting older!)

Joe.