T&T: 3M 4000 UV polyether caulk sucks!

[Keith]

Well, I do live on the Gulf coast, and Houston and Pasadena have lots of
refineries and chemical companies. I really doubt they are the cause. This
particular spot is a door frame. It's finished with Honey Teak, and the
fiberglass had been waxed in the past. Neither would cause a contamination
problem that would cause this. There have been no aggressive chemicals used
in the area, only soap and water and some more wax. 

I didn't have time to write a long message earlier today because I was "in
the middle of it". I wanted the vast, unpaid and appreciated research group
to have time to provide feedback today so I could make a choice for
tomorrow. One thing I noticed was the inconsistency of the caulk. Along one
vertical caulk line, some spots were totally gone, some basically burst into
powder when I scraped them, some were rubbery (as it should have been) and
underneath the skin, some was actually sticky as hell. My first thought was
that this was a bad batch of 4000 that wasn't blended well. The white
pigment is probably titanium dioxide. Looks like the powdery parts had a
much higher loading than others, and maybe that's what happened in the parts
that were gone. It was really astonishing how different this stuff was just
12" away from the last section. 

I have gotten a couple of recommendations for LifeSeal, which seems to be a
combination of silicone and polyurethane. Also got one for a couple of Sika
products, which I'll look into to see if I can get them locally, and what
they're made of. 

Thanks as always for the help, and I'll let you all know how it comes out. 



Keith
_____

-----Original Message-----


Just for the sake of discussion, consider this. Maybe the problem is not 
the UV. Suppose it's some kind of contamination. Is there any chance a 
silicone has been used in those locations in the past? Or, for that 
matter some other chemical? I really don't have any clear idea what it 
might be, but since your symptoms are so variable it makes a fellow 
wonder about chemical contamination.

Sympathetically,

Mike

_________________________