Silicone

[Alan Wheeler]

Well actually I do adhere the bolts into the holes. OK, first let me explain in more deatil as to why I am doing all this.
In a normal install situation, as discussed by Sean and Paul and others above, backing plates would be the norm and quite adiquate.
In my situation, it's a little different. The boat had never sailed before we bought her. so had never had anything fitted to her. But to be worse, she had not had area's for winches and deck fittings fitted to her during construction either. That part of the story should be placed in the other forum on " bad things previouse owners did":-)
Originaly there was just a Pilot house and the entire boat was set up as a launch only. Steering position was even bad. To get us going, I mounted the primary winnches inside the Pilot house, but there had been no provision for mounting them. So I placed them in a position I wanted them and then worried about how I was going to hold them down. The position was good in the sense that structuraly it was very solid, but I had no way of getting to the area from underneath to put bolts right through and use a backing plate. I also needed another 1" in height. So I turned up on the wood lathe a hardwood (Jara) plate for the winch to sit on. I epoxied that to the cabin top and screw it down with heavey Bronze screw. I then drilled right through all that and fitted the winch base using "coach bolts". These are large wood screws, 1/2" thick with hex heads on them so as you can use a socket driver to screw them in. So......now you're upto play.......
I didn't trust the fact that the winch was not through bolted. So I used the adhesive as additional holding. I squirted adhesive into the screw holes to ensure no water could ever run down the threads and into the timber.
So now came the time to remove and relocate to the new position. Unscrewing was actually quite simple. They were not hard to remove at all.

[roverhi]

Sillycone is the spawn of the devil. My first boat came from the factory with everything bedded in the sh*t. Spent my first year of ownership R&R'ing every fitting on the boat because of the leaks. Sillycone will bond to some materials, especially porous materials, but it doesn't bond for beans to FRP gel coat and metal fittings. When they are subject to stress, the seal goes away and leaks become a water fall. What was the most frustrating part of it was the stuff leaked like a sieve but was damned hard to remove so I could rebed with Life Caulk.

What really makes Sillycone bad is it is a bear to work with. Hard to clean up and even a slight film of missed residue will collect dirt and look terrible. Trying to clean up any missed areas is one of the most frustrating parts of sillycone. Haven't found anything that will cut the cured stuff. If any one knows of a chemical that will do the job, let me know. Sillycone also shrinks when it cures. This can leave voids or holidays if you cinch up the part tight from the beginning.

One of the PO's on my current boat was a compleat idiot. They used sillycone on everything they put down which is only a small part of their stupidity. So I'm once again tearing off every one of those fittings to rebed with LifeCaulk as there are numerous leaks where the sillycone was used.

I really like LifeCaulk. I've had a 35 year history with the stuff and it's still going strong on my old boats. It remains pliable and holds a bond even with repeated torquing of the fitting. The fittings can be removed with a little effort if need be. You can clean it up with Acetone after it's cured and with paint thinner before it cures. It's relatively easy to work with, at least compared to Sillycone and 4200. It's less viscous than 4200 so easier to spread around and seems a bit more sticky in clinging to parts.

I haven't used 5200. The main reason is its reputation as a permanent adhesive. Hear it's near impossible to get fittings up that have been bedded in it. So far haven't bedded anything down that I thought would be down permanently. When I redo the chainplates, will probably use 5200 cause I don't want them to leak and hopefully will never have to take them up again.

Both 5200, 4200 and LifeCaulk will cure in the presence of water, in fact require moisture in the air to cure. For fittings that are going right back in or already in the water, they are ideal.

One word of caution that has already been mention in other posts, some plastics don't get along with 5200/4200/LifeCaulk. Check with the manufacturer of any plastic fittings to see what bedding compound works for them. Personally, it a part doesn't work with LifeCaulk, I wouldn't consider using it.

Not sure when 5200 came into wide use. In the '70s, a white sticky bedding compound was probably LifeCaulk or 3M 101 sealant. Both are Polysulfides. IIRC, 5200 was not around then or hadn't gained widespread acceptance.

Aloha
Peter O.

[FrankZ]

Fair enough Alan. I used polysulfide on my winches (and other hardware) and made sure to get goop into the hole. It isn't as tenacious as polyurethne though.

I did find some teak hand rails that were put down with polyurethne by a PO. Those came off in little pieces during the refit. Oh that was a "fun" day. I actually considered drilling out the bolts.

[GordMay]

As Peter O indicates, Polysulfide (Thiokol )sealants should NOT be used on many plastics, such as acrylic (Plexiglas) or polycarbonate (Lexan).
Polysulfids are the slowest curing of the three main sealant types.

BoatLIFE:

- LifeCaulk (1000 series) is a 1-part polysulfide sealant, as is 3-M “101”.

- Life Seal (1100 series)is a hybrid combination silicone and polyurethane sealant, which promises a longer-lasting (than silicone), yet more removable (than polyurethane) seal for portlights and other plastic fittings.

LifeCaulk Solvent & Cleaner (#1056) is a general purpose solvent that removes uncured polysulfide sealant.

Release Adhesive & Sealant Remover (#1288) is advertised to remove cured silicone (but not the oil residue), polyurethane, and polysulfide.

and

DeBond Marine Formula claims to clean-up and remove polyurerehane sealants, as does AntiBond 2015.

Acetone is often recommended for cleaning old polysulfide & silicone sealed surfaces. It doesn’t work very well. When attempting to clean silicone oil off contaminated surfaces, it is very common for it to redeposit back onto the parts that were originally affected, or onto other parts that entered the process free from silicone.