Windows and gaskets that leak

[MyronL]

There are leaks from badly done or cracked old caulking, leaks from dried up, shrunken seals and gaskets, leaks around rivets, wind-driven leaks from horizontal rain, leaks galore, we cannot escape them. They can be obvious, sneaky, or stupid. I hate 'em, especially the stupid, sneaky ones I don't know are at work, then I lift up a seat cushion and find it discolored and damp and danky under there. Wish my windows would never leak, but inevitably, they will.

The back window on my '81 has a rough opening of 22 1/4 inches high by 44 inches across. It has a center pane slider. All 3 panes are plastic. It's the original window. Not the greatest design, unfortunately. Plus, it was caulked in place with gobs of silicone, likely by the previous owner, since this trailer was a home-assembled kit. I mention that only because I don't think the pros use silicone to seal windows.

Besides the sneaky leak, there is one other thing about this back window; it isn't flat across and has no screen. It conforms to the curvature halves of the '81 Burro shell. The big thing for me is this leaky back window is of such unique size and shape that its specifics have moshed my search for a newer, affordable replacement. Rain and flies, rain and flies.

A few months ago I got lucky on ebay and replaced 3 other windows with terrific, newer windows for bargain prices. Not an exact fit to my rough openings, but I tackled the serious shell modifications needed simply because I wanted to do it. (A man thing.) Well I don't feel like doing that extra work this time around. ( ...My wife will confirm this as being another man thing.) Now many months of searching is gone by and have found no window close enough in size to use in that rough opening. How long can I stay this course? Got to fix that leak.

Had a major rain recently. It forced me to finally isolate the source of the window leakage. It wasn't horizontal wind-driven rain pushing through the vertical edge of the flexible plastic center pane like I thought. Rain was coming in at a bottom radius corner where the seal-gasket slipped out of position. My strategy of wait and hope for another window is not working. Time to get up out of my ...commander in chief's chair.

I cut out the nested, rubber front face-trim gasket holding the plastic pane in place and run it through a solvent soaked rag to get it clean. Sure enough, that skinny seal gasket behind the pane was dried up hard. There's your trouble!, I said. This here is a clear need for new butyl caulking!

[MyronL]

There has been discussion on the merits of silicone versus those of butyl as a caulk.

Silicone, I have found, has the ability to stick tight as hell. No doubt that's why it was used to seal the window frame to the fiberglass shell. But silicone is also finicky, stubborn, vindictive, inconsistent, sloppy, gooey, and will form air pockets where you don't know it. Also, I doubt the long term reliability of silicone caulk. Now, these are my personal opinions. Not scientific. I just know I am right. So, for my windows, I prefer butyl.

Butyl is flexible rubber, durable, sticks tight as ticks, and it is used to seal windshields in the auto industry. It comes as wax paper-clad tape and tubes you can put in a standard caulking gun. The tape form is far more user friendly. I found a roll of it an inch wide by 30 feet long that with the cost of shipping cost me the same as a 15 foot roll I saw at an auto supply store. About $13. A guy in Kentucky, RV Parts Etc., on ebay. He listed it as Mobile-Lastic Butyl Tape Seal.

I cut a thin strip of the butyl tape to reseal the plastic pane in place and used a flat putty knife to re-set the front gasket. Easy to do with the entire window still hung in the Burro. Then unscrewed the inside clamp frame and removed entire unit. Took a while but with a putty knife and a flat crow bar I peeled that window off. Then used knife and lacquer thinner to get every last bit of the silicone off the egg. Skuzzy silicone fought me all the way but I got it done.

It was while cleaning up the aluminum unit down in my shop I realized that black stuff in an inside channel wasn't dirt. It was an old spline from a screen that covered thae sliding center window pane. Another Eureka moment. Got new spline and screening. No more flies now, either.

[Alf S.]

There has been discussion on the merits of silicone versus those of butyl as a caulk.

Silicone, I have found, has the ability to stick tight as hell. No doubt that's why it was used to seal the window frame to the fiberglass shell. But silicone is also finicky, stubborn, vindictive, inconsistent, sloppy, gooey, and will form air pockets where you don't know it. Also, I doubt the long term reliability of silicone caulk. Now, these are my personal opinions. Not scientific. I just know I am right. So, for my windows, I prefer butyl.

Butyl is flexible rubber, durable, sticks tight as ticks, and it is used to seal windshields in the auto industry. It comes as wax paper-clad tape and tubes you can put in a standard caulking gun. The tape form is far more user friendly. I found a roll of it an inch wide by 30 feet long that with the cost of shipping cost me the same as a 15 foot roll I saw at an auto supply store. About $13. A guy in Kentucky, RV Parts Etc., on ebay. He listed it as Mobile-Lastic Butyl Tape Seal.

I cut a thin strip of the butyl tape to reseal the plastic pane in place and used a flat putty knife to re-set the front gasket. Easy to do with the entire window still hung in the Burro. Then unscrewed the inside clamp frame and removed entire unit. Took a while but with a putty knife and a flat crow bar I peeled that window off. Then used knife and lacquer thinner to get every last bit of the silicone off the egg. Skuzzy silicone fought me all the way but I got it done.

It was while cleaning up the aluminum unit down in my shop I realized that black stuff in an inside channel wasn't dirt. It was an old spline from a screen that covered thae sliding center window pane. Another Eureka moment. Got new spline and screening. No more flies now, either.

Hi: Thanks for the pics...It seems there is hope for me yet as I have leaks also...With the amt. of rain we have had I should have bought an ARK!!! Have you tried H.P. sauce on your "EGGS" instead of "SILLY CONES" Alf S. North shore of Lake Erie

[pjanits]

Take some of that leftover butyl rubber tape and pop off all your running lights and tail/stop lights and smush some in the holes for the wires and screws.
I had waterfalls in my Burro from these spots.

If you look closely you will see the trails the leaks left on the inside wall.

PS the windows were installed by the factory on my 81 which was a kit. They used some weird thick tannish stuff similar to silicon.

The only kit parts were the inside doors ,vent and fittings , etc.

After taping my rear window ( it's the same as yours) no leaks!!

[MyronL]

Excellent suggestion, PJ. (?Waterfalls? ) Dunnit.

PS: Saw some weird tannish stuff. It possible the silicone was preivous owners' addition of caulk to the sealed window from inside the cabin, by removing just the lock ring.