Whats the best goop to seal window frames? Butyl tape or 3M 4200, or??

[magentawave]

What is the best stuff to seal window frames with? I was thinking of using butyl tape but then I heard good things about 3M 4200 Marine Fast Cure 4200 Adhesive Sealant :3M US. Besides epoxying them in permanently, what is the consensus for long lasting window frame seal goop that does allow one to replace the windows later if needed?

Thank you.

[DennisDW]

Having just done this, don't use the 4200. I thought that 5200 would hold nicely on my fixed port lights. I ignored the warning not to use on glass because I etched the sealing surface first. It was an epic fail. the bond broke away from the glass in less than 2 days. It had nothing to do with cure times. I bought several tubes of corning 985 I think from McMaster carr. It was cheaper and has held like champ. No drips.

I believe the butyl tape would work well too.
Cheers,
Dennis

[magentawave]

You said don't use 4200 but then you said the problem you had was with 5200. So you don't recommend either of those? I just did a search for "corning 985" and nothing comes up.

[Reefmagnet]

A local supplier recommended a non hardening mastic used for automotive windscreen sealing. This stuff is black and of chewing gum consistency. Obviously the window needs to be held in place with some other attachment as this stuff is just for sealing, but it seems to work extremely well and any that squeezes out of the joint is easy enough to clean up.

[Chenega]

Dow 795 from mcMaster.com - hands down. (20 yrs marine trades)

[AnchorageGuy]

I agree that the 795 is your best for glass or plastic. Been using it for years. Chuck

[roverhi]

Automobile windshields are held in with butyl. It remains pliable forever and and can cope with the expansion of the glass or plastic that 4200/5200 can't. The stuff you buy at auto parts stores is black and kind of nasty to work with because of the color. You can get some good quality grey butyl from this guy.Need Butyl Tape ?? Photo Gallery by Compass Marine at pbase.com

[DennisDW]

Sorry, I used Dow Corning 995 McMaster-Carr and it's worked well. The 795 is probably great too. The're both "structural Sealants" and have good adhesive qualities. They are used for sealing big windows in big buildings. A decidedly critical application.

By the way, I had gotten this advice from the Forum before I ignored it and made a mess of things by being hard headed. Don't use the 4000/4200/5200 products for windows. Please don't let my wife know I admitted to hard headedness. She should never be encouraged.
Dennis

[zeehag]

i use sikaflex. perfect. on the window i remove for window unit air cond i use silly cone---works great, and removes easily for re installations of seasonal stuff is good.

[Azul]

Per Compass Marine, this is one place where silicone is useful. Butyl tape will work but it is easier to get a good seal with silicone, and you have to order it instead of going to Home Depot.

Need Butyl Tape ?? Photo Gallery by Compass Marine at pbase.com