3m 4000UV only lasts a couple of year and turns to a past

[Candide]

Having and issue with 3M 4000UV around the windows. Boat is in south florida year round. I have a plastic frame that goes between the glass and the fiberglass superstructure for all the windows. The glass to frame I use Dow 795 and it lasts forever however it is silicone based. Between the plastic frame and the superstructure, I have used 3M 4000UV but after a couple of years it turns to a sticky paste and basically falls off or washer away. I have replaced twice and getting ready to do it a third time. Should I use something else? Should I consider using Dow 795 between the frame and the fiberglass? Also wondering if I am painting areas on the boat if I should just fiberglass the frame (epoxy / fairing compound) and paint over it and be done with sealants? Not overly worried about ease of changing a window as if that is needed it will be a massive mess of a job either way.

 

[jgtrucking]

Just curious where do you spend your time? As in what Lattitudes?
I use 4000UV for not only windows, but all sealant applications above the waterline. 5200 is too hard to ever take apart. And well, I have yet to experience the symptoms you are having. I have some 6 years in now, just as the day I applied it.

 

[Candide]

Just curious where do you spend your time? As in what Lattitudes?
I use 4000UV for not only windows, but all sealant applications above the waterline. 5200 is too hard to ever take apart. And well, I have yet to experience the symptoms you are having. I have some 6 years in now, just as the day I applied it.

Boat is in south florida year round.

 

[jgtrucking]

Boat is in south florida year round.

Well I'm in TN and AL alot, unless we travel, then further north. is there any chance you bought a tube that was really old? I ziplock bag my open tubes, and store in the fridge... use again sometimes a year later, and again no problems like this *shrug*
I hope an answer that makes better sense comes out!

 

[Comodave]

I quit using the 4000 because it didn’t last. I went to Sika 291 for general work and 295UV for things like plexiglass.

 

[DDW]

Many years ago this was a complaint about 4000UV, 3M changed the formula in response. I've used a lot of it before and after the change, haven't found many problems, even with 15 years old installations. You could always use 3M 4200 which is a polyurethane like Sika, but it will yellow in the sun over time. 4000UV is a polyether, and does not yellow.

 

[NoRain]

GE UltraGlaze SSG4000. CRL Black GE® UltraGlaze® Silicone Structural Glazing Sealant | CRL This was the product of choice of the company that built my enclosed glass bridge. Also a fan favourite of the glazing industry.

 

[tiltrider1]

3M 4000 to 5200 yellows when exposed to sunlight. It works great as a sealant but not as a glazing compound. I use Sikaflex 295 when installing glass or plex into a window frame or if my frame has gaps between it and the GRP structure.

 

[Larry M]

I feel your pain. It’s too bad that it is that bad and I don’t get 3M? Most of their products are good. But I’ve used it twice and got burned both times.

 

[Flatswing]

Having and issue with 3M 4000UV around the windows. Boat is in south florida year round. I have a plastic frame that goes between the glass and the fiberglass superstructure for all the windows. The glass to frame I use Dow 795 and it lasts forever however it is silicone based. Between the plastic frame and the superstructure, I have used 3M 4000UV but after a couple of years it turns to a sticky paste and basically falls off or washer away. I have replaced twice and getting ready to do it a third time. Should I use something else? Should I consider using Dow 795 between the frame and the fiberglass? Also wondering if I am painting areas on the boat if I should just fiberglass the frame (epoxy / fairing compound) and paint over it and be done with sealants? Not overly worried about ease of changing a window as if that is needed it will be a massive mess of a job either way.

My experience with 4000UV matches yours in Southern Sun. My local (high end) boat refinishing professional recommends either Dow or the Sika. Typically Dow lasts the longest. It worked for me.

 

[rwaldrop13]

Having and issue with 3M 4000UV around the windows. Boat is in south florida year round. I have a plastic frame that goes between the glass and the fiberglass superstructure for all the windows. The glass to frame I use Dow 795 and it lasts forever however it is silicone based. Between the plastic frame and the superstructure, I have used 3M 4000UV but after a couple of years it turns to a sticky paste and basically falls off or washer away. I have replaced twice and getting ready to do it a third time. Should I use something else? Should I consider using Dow 795 between the frame and the fiberglass? Also wondering if I am painting areas on the boat if I should just fiberglass the frame (epoxy / fairing compound) and paint over it and be done with sealants? Not overly worried about ease of changing a window as if that is needed it will be a massive mess of a job either way.

We were in Ft Myers FL and never used the 3M products. I used Boat Life brand sealant, recommended by a vendor/friend/fellow old Coastie in the marina, who used it on their boat exclusively. I had sealed windows, and never had a problem. It stayed flexible even on the radar arch where I used it to seal under a patch I fabricated using starboard after removing a defunct antenna.

https://www.amazon.com/Boat-Sealant-Lifeseal-Cartridge-White/dp/B001441AEQ

 

[tiltrider1]

I think people miss use various products. 3M sealants are good products but they were not designed to be glazing compounds. Any product that oozes out should be wiped off. If you are trying to fill gaps you need a different product.

 

[Brooksie]

I would highly recommend Life Seal (not Life Caulk). Tape everything off and don't get it on anything tou will paint in the future. Acts like silicone but sticks much better. I've had an exposed bead of it on the top of my rubrail (plastic to FG) for 25 years and still good.