Penthouse Issue: canvas-to-van-roof gasket

[JohnandMandi]

We now own the van rallypanam added the top to and we haven't had any issues with that seal. A little rain got in when we drove it home to Florida from San Fran through one gigantic serious storm (spent over a day driving in it). We've since found some cracking in some fill that is on the van roof, unrelated to the rubber seal, and believe that's the culprit. We'll be seam sealing that soon in preparation of a color change.

Not sure if this would work but the butyl that was used to seal the back windows in our van came off quite easily with acetone. Same for what was on our donor windows we then installed.

[Viva]

I've always used mineral spirits to clean up/after butyl. I think that's the "standard" solvent one would use (which isn't to say others wouldn't work). I do typically prep clean a surface with either denatured alcohol or acetone.

[MountainBikeRoamer]

Much thanks for all the continued info and discussion.

UPDATE:

While I haven't taken pictures yet, I HAVE dug into the seal area (literally) by scraping much of the excess butyl rubber "goo" out of the canvas-seal-roof sheetmetal area. I've pulled up a TON of it already....it appears someone was pretty generous and eager to apply a ton of it to the exterior in this area.

It doesn't seem that I have compromised the water-proofing of this area by doing so yet, as I also scrubbed down the canvas exterior with soap/water (was pretty dirty from long-term storage) and hosed it down pretty aggressively.....(the rain gutters were FULL of standing water for a long time!) and nothing seems to have leaked inside.

My plan is to carefully clean away as much as I can just be carefully scraping (using a wood tongue depresser, so as to avoid tearing canvas or scraping paint) and then do the final cleanup using one of the mild solvents you guys have mentioned.

Incidentally:
I talked on the phone several days ago to a individual named Peter at Sportsmobile Fresno about this issue, and he recommended using "Acrysol" to do the Butyl Rubber cleanup, it's what their Techs use when they are doing Penthouse builds/repairs and working with this Butyl Rubber. This gentleman I spoke with indicated that it was safe for use on the canvas as well. (I'm personally of the suspicion/opinion that I should be prepared to have to "re-waterproof" the canvas in this area after doing this, however.)

Additionally ---
Some guys that I work with that do Automotive Paint work (I work in an Automotive Design Studio) mentioned that they use PPG DX330 "Acryli-Clean" solvent (wax and goo remover/degreaser) to clean up Butyl rubber, and that it's potentially a more mild product (safer?) on paint surfaces than even the "Acrysol."

I'll keep plugging away at this!
Will post pics when its a bit cleaner, so you can see how the factory rubber gasket seal seems "submerged" (or rather, collapsed down into the stamped-into-the-sheetmetal "trough" that the factory roof still has that runs lengthwise, about 7 inches inboard from the rain gutter.)

Again --
Cheers/Best Regards/Thanks for sharing your knowledge/experience.

This community makes the Sportsmobile ownership adventure pretty special.

[rob_gendreau]

When I talked with SMB about leaks at the base of my penthouse they suggested using Seam Sealer, that stuff you use on tents. I think it's urethane. It goes on pretty easy and is clear, and has about the right viscosity to flow into some areas without running all over the place. I've still got a section to do; I didn't originally seal the double rubber rand and I think that's still leaking (like door seals it seems to accumulate some dust and debris in the folds, which then allow water to get in).

[MountainBikeRoamer]

Hey, just wanted to post an update, keep this thread somewhat current.

I still haven't taken photos of the area of the penthouse-canvas-to-steel-van-roof gasket area to show you.

BUT: In the course of reading this site regularly, however, I came across a photo of another SMB that has what looks to be identical amounts of butyl rubber residue/staining on the outsides of their penthouse canvas, in the same area. This looks visually almost identical to what I see on my penthouse roof.

Cropped photo here:


I have poked around this area of my SMB quite a bit now, and done a LOT of cleaning/scraping out of the excess black butyl rubber that appears to have "squeezed out" of the gasket mating area over the years, and then "wicked" its way up the sides of the canvas on the outside. I am starting to assume that this is something that is occasionally common on older SMB's of this vintage, seeing as both this pictured SMB and mine are from the early-to-mid-90's. (perhaps the butyl rubber heats up and gets more "liquid" during the summer months, and oozes out of the seal, to where it can then stain and accumulate on the outer bottom of the canvas.)

Fairly confident I can clean this up and make it presentable with just a lot of elbow grease (cleaning only) and wont' have to separate/re-seal the gasket-to-roof area.

[Pntyrmvr]

Hi,

I was just looking at a thermo pane unit that needs replacing in one of our home windows and noticed butyl is seeping from the frame out and onto the edges of the glass.

This is fairly common in older windows around here.

I wonder if the creeping butyl issue is what you and the other penthouse roof are experiencing?

Regards,

Gavin

[JohnW]

Thanks for the motivation to remove the butyl rubber "leak" on our 1996 RB-21. We have been looking at the canvas stain for the eight years that we have owned the van.

The stain was about 14 inches by 2 inches. Used a plastic putty knife to remove the excess butyl rubber off of the roof painted surface. Used lacquer thinner on several paper towels to remove the butyl rubber from the painted surface and the canvas with no apparent damage to the paint or the canvas. 15 minutes, and
problem solved.

-John

[MountainBikeRoamer]

JohnW -- that's great to hear. Glad you had fairly easy/quick success, and that you reported back on it.

A month or so ago I scraped all the excess rubber goo off the outside surfaces, but I've been delaying doing the final cleanup with a thinner/degreaser, as I wanted to be sure I selected one that wouldn't attack the canvas or paint. Since it sounds like you had good results with the lacquer thinner, I'll probably do the same thing.

While it seems that this is not uncommon on these older SMB's, it appears to not be a cause for concern...and it's great to know it's so easily remedied.