Re-bedding Windows: 3M-4200 v. Butyl Tape

[saildork]

I'm Re-bedding the windows on my Catalina 22 using the kit from Catalina Direct. I replaced the windows into the new glazing channels using Dow Corning 795 from the kit and then into the frames, also using the DC 795 per the instructions. Now I'm ready to put the windows back into the cabin. The kit includes 3M 4200 for this job. The instructions call for the 'Don Casey method' of applying the 4200 and partially tightening the screws the first day and then completing the tightening the next day.

The old compound that I removed from the frames and the residue left on the gelcoat seemed more akin to butyl rubber than 4200. I could tell, however, that it came out of a caulking tube. I use the 'Maine Sail method' for mounting deck hardware using the butyl tape. It's great stuff and the best way I've found for mounting thru-bolted hardware. I'm inclined to use the butyl tape for the windows as well, but I'm not sure. Any suggestions out there?

[Faster]

I wouldn't use 4200 for this.. butyl should work if you're happy with that, but I expect 795 would work here too.

[ccriders]

Saildork,
Hey I just did this using the Catalina kit. I did not use 4200, but butyl tape instead. So far it has worked just fine. And, the butyl tape is cheap at the local RV store and is very easy to use. No mess whatsoever. Now I have a big tube of 4200 with no place to go.
John

[saildork]

Since the 795 is a silicone-based bedding compound, I am not inclined to use it to seal the window frames against the gelcoat. I do like the ease-of-use of the butyl tape. I guess I should call the Catalina Direct folks and ask them why they would use the 4200 vs. butyl tape.

Anyway, thanks for your input, Faster.

Pat

[saildork]

Originally Posted by ccriders

Saildork,
Hey I just did this using the Catalina kit. I did not use 4200, but butyl tape instead. So far it has worked just fine. And, the butyl tape is cheap at the local RV store and is very easy to use. No mess whatsoever. Now I have a big tube of 4200 with no place to go.
John

Thanks for your input, John. I called Catalina Direct and they could think of no technical reason for not using butyl tape...a matter of personal preference, really. I'm going to use the butyl tape. I find it easier to work with, and if I have to re-do any of the windows, I find the butyl tape easy enough to remove and reapply. Thanks again.

[Faster]

I'm sure you'll do OK with butyl tape.. just try not to squeeze it all out as you tighten the window into place.

FWIW I do know firsthand that DC 795 cleans up easily if you ever need to redo that seal and it works just fine against gelcoat. Again it's important to retain some 'gasket thickness' when done.

[AirborneSF]

I've used the 4200 on my C&C 26, and it is leaking again. These are 'flush' mounted portlights, and I was thinking of 1/8 thick 'weather stripping', this time around. The tape idea sounds good, I know I need 'movement', how tight can you go with the tape?

[saildork]

Originally Posted by AirborneSF

I've used the 4200 on my C&C 26, and it is leaking again. These are 'flush' mounted portlights, and I was thinking of 1/8 thick 'weather stripping', this time around. The tape idea sounds good, I know I need 'movement', how tight can you go with the tape?

Airborne, as Faster states above, just don't tighten your windows down so tight that you squeeze out all the butyl rubber. This stuff has the consistency of plumber's putty, roughly. It stays workable and flexible forever. I should think it would work in your application.

Maybe someone else out there with windows like yours has tried it successfully. Anyone???

[copacabana]

Sailordork, I'm going to try the butyl route on one portlight this weekend (if it doesn't rain). Never tried it before, but from my research it seems to be a viable option for sealing portlights, but not for fixing them in place. That requires an adhesive caulking or screws, bolts, frames etc.
I'm going to use some two-sided automotive adhesive tape as a spacer and to prevent the buytl from being squeezed out from around the edge of the portlight. I'm hoping this will contain the butyl permanently in place. My portlights are through-bolted to the cabin sides and I intend to use butyl on the bolts as per Mainesail's instructions in the butyl thread. I'll take some photos of the job and post them later. My thinking is that if the butyl route works, it is a practical, inexpensive solution and one can carry plenty of extra butyl tape on board for future work without worrying about it drying up or expiring. Please let us know how your windows come out on your Catalina, as we can all learn from each other's experiences with butyl.

[jarcher]

There is a ton of discussion about what to bed windows with on this board. Windows are a special case and need special adhesives. I'll try to find the thread and post a link. Its worth the effort to rea it, as there is a pile of good information there.