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Window caulking bleeding?
- Thread starter Capt. Art
- Start date
I don't think it's mold. This is the caulking that's used around your auto windshield glass. It almost looks like Black Tar? When I use just plain Boat Soap to wash the glass it if I wash the sealed strip around the glass it turns the water black as you hit it? I'm wondering if this sealer ever needs to be resealed? Really strange? I've never had this happen?
I think that black tar like stuff used to mount windows is called buytl. Rubber mounting strips frequently do what you describe but I dont think I have seen the soft buytl do that but it is'nt it usually out of the weather behind something??? you might ask Carver customer service.
It may be mold/mildew from dirt trapped in the channel. I see this on my side portlights every time I wash the boat - normal wishing will remove it. As you wash does it subside or will it just keep coming without any letup?
Is the windshield bonded into a frame or is it held in a gasket within a fame? If it is bonded and it is glass, then the adhesive/sealant is probably a urethane-based system. It shouldn't do what you are describing. The only way I can think that something like that would happen is if the sealant was degrading badly, like really falling apart.
Is the windshield bonded into a frame or is it held in a gasket within a fame? If it is bonded and it is glass, then the adhesive/sealant is probably a urethane-based system. It shouldn't do what you are describing. The only way I can think that something like that would happen is if the sealant was degrading badly, like really falling apart.
I think you need to talk the manufacturer, but here is a complete guess on my part.
The black is probably carbon black - this is used heavily in the rubber and plastics industry as the source of black in formulated compounds. One of it's functions in compounded rubbers and plastics is to block UV light simply through opacity. If this is readily washing off then that suggests that the base resin in which the black filler is held is degrading, releasing the filler. If my guess is accurate then the problem will likely continue and progressively get worse over time.
The black is probably carbon black - this is used heavily in the rubber and plastics industry as the source of black in formulated compounds. One of it's functions in compounded rubbers and plastics is to block UV light simply through opacity. If this is readily washing off then that suggests that the base resin in which the black filler is held is degrading, releasing the filler. If my guess is accurate then the problem will likely continue and progressively get worse over time.
My windows were installed using buytl. I had a very leaky port window. The only way to fix it was to completely remove all of the butyl, thoroughly clean the area and reinstall the window with new buytl. It never "ran" or showed any staining. It just leaked do to deterioration.
Capt. Art,
I doubt that the sealant around your windows is butyl, unless it is covered by some other material. Reason being is that a butyl sealant, whether a tape or liquid, is inherently tacky and would pick up a tremendous amount of dirt. Plus, it wouldn't have the strength to hold the windows in place.
I have seen rubber gaskets do what you're describing. If it's the gasket leaching carbon black, wipe the surface with lighter fluid (naphtha) and then coat the rubber with a vinyl/rubber protectant.
Bob
I doubt that the sealant around your windows is butyl, unless it is covered by some other material. Reason being is that a butyl sealant, whether a tape or liquid, is inherently tacky and would pick up a tremendous amount of dirt. Plus, it wouldn't have the strength to hold the windows in place.
I have seen rubber gaskets do what you're describing. If it's the gasket leaching carbon black, wipe the surface with lighter fluid (naphtha) and then coat the rubber with a vinyl/rubber protectant.
Bob
Capt Art-
What you are seeing is indeed the caulking slowly degrading. Most likely the product used to seal your windows was black Sikaflex caulking (Product No. 295UV or 296).
http://www.sikaindustry.com/ind/ipd-marine/ipd-ma-products.htm
These products were used by many boat companies for years to seal windows.
The only way to cure the problem is to dig out all the old caulking and replace it. Lots of people have had great success with Dow Corning 795 Commercial Grade Sealant. This product is used widely in skyscrapers with glass skins.
http://www.dowcorning.com/applications/search/default.aspx?R=264EN
P.S. I've been through the same problems you're having on my boat and I will be re-doing my salon windows this winter as well.
Good luck!
What you are seeing is indeed the caulking slowly degrading. Most likely the product used to seal your windows was black Sikaflex caulking (Product No. 295UV or 296).
http://www.sikaindustry.com/ind/ipd-marine/ipd-ma-products.htm
These products were used by many boat companies for years to seal windows.
The only way to cure the problem is to dig out all the old caulking and replace it. Lots of people have had great success with Dow Corning 795 Commercial Grade Sealant. This product is used widely in skyscrapers with glass skins.
http://www.dowcorning.com/applications/search/default.aspx?R=264EN
P.S. I've been through the same problems you're having on my boat and I will be re-doing my salon windows this winter as well.
Good luck!