Best bedding compound/sealant?

[Bigjim]

I just bought a Columbia 10.7 that has seen some better years. There are a bunch of leaks coming from the cabin top and deck. My plan is to re-bed all the deck hardware before going into the water this spring.

Lots of people recommend 3M 4100 adhesive/sealant, but I can't find it anywhere. It looks like it was replaced by 3M 5200 and people warn NOT to use that.

So then, what's the best sealant/bedding compound that offers good waterproofing but remains flexible in extreme midwest weather? I'd like it to last a few years through winter and summer extremes.

Most people say to avoid silicone products.

[SailsWithFists]

Originally Posted by Bigjim

Lots of people recommend 3M 4100 adhesive/sealant, but I can't find it anywhere. It looks like it was replaced by 3M 5200 and people warn NOT to use that.

It is 3M 4200, which is still available. I would not recommend using an adhesive for items that do not need to be "adhered."

Dolfinite bedding compound will ALWAYS stay flexible. Butyl tape can also be a good choice in some situations for bedding.

Silicone has it's place, but proper application is required, and most people do not know how to apply it in a manner that makes it last.

[travellerw]

Sika makes good products as well. Sika 295UV is very good.

You can definately find 3M 4200 on the internet (probably even Amazon).

[Fiveslide]

Those people are probably meaning to recommend 4200, or perhaps even 4000.

Been years since I used either, seemed like 4000 had a bit more shrinkage as it cured than I expected. Not a big deal for creating seal between bolted down stuff and the deck, but didn't work that great for sealing larger gaps, in my case the gap between glass and its frame.

I will also advise against the use of 5200, except in a very few appropriate applications. I curse the man that told me use that crap for everything, which I did before I knew better.

[Stu Jackson]

Maine Sail's Bed it with butyl. His particular butyl is superior to other butyl tapes sold elsewhere. He did his homework to get it made. Read his website. Only stuff many of us use. The ONLY places I still use silicone on my boat are the Beckson ports (they recommend it) and in replacing teak bungs.

[PDScott]

Butyl rubber It may be old but is still imho the best

[roverhi]

I like LifeCaulk. Has worked for me for a 1/2 century without any problems. Doesn't harden up in the tube after it's opened as fast as the 3M products and easier to clean up. Butyl works but takes longer to do installs oozes out when it gets hot so needs to be cleaned up.

There's nothing wrong with 5200 as long as you don't want to ever remove the fitting. Stuff sticks like glue. There is something called Debond that will dissolve 5200 and make removal easier. I've found strong steady pressure like from a halyard winched in hard will eventually pull a fitting off. Steady pressure, not too much, and it will release, eventually. If you try and force a fitting off may suffer it coming off with the underlying gel coat still attached to the fitting.