Installing Aluminum Trim

[Capebuild]

I'm trying to decide what would be the "best" sealant, or method of sealing, the aluminum trim to the aluminum sheeting (like the corners where the roof meets the siding). I can think of 3 materials but not sure if there are advantages of one over the other:
1) Butyl Tape
2) a sealant like Pro-Flex RV
3) VHB Tape

I'll be using aluminum moldings from Vintage Technologies and in addition to the sealant method will also use stainless screws to attach the moldings.

Asking for any thoughts and/or suggestions.......that would be helpful.

Thanks very much!
John

[halfdome, Danny]

John, I use OSI Quad clear.
It’s for aluminum and other uses, great stuff and cleans up with lacquer thinner.
Danny

[dmdc411]

I used OSI clear, and white. Put it between layers on roof joints, under the trim, and on every screw shank at install. Messy, used lots of tape, and alcohol for clean up! Not a leak after 9 or so years. Butyl tape attracks dirt, and in my opinion, it pushes out from expansion and contraction, allowing water in.

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[Graniterich]

I swear by lexel!

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[noseoil]

Low tech here, butyl tape & no problems after a few years of use.

[randb]

Absolutely agree, 6 years on still no leaks. Butyl tape is great. Easy to work with too.

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[airdonut41]

One more quick comment: VHB tape isn't really a sealant. It's great stuff, but it won't serve an important job here: deforming around your fasteners or around corners. Butyl tape (as well as anything that comes out of a caulk gun) should do a good job of squeezing into nooks and crannies before curing. I did use VHB tape for attaching my solar wire bulkhead feedthroughs (couldn't use fasteners in my 1/8" roof), but I caulked around the outside to form the actual water seal. I used butyl tape for most of my seals and backed up where appropriate with some all-weather caulk.

[lfhoward]

Butyl tape and no leaks since installation in 2016. I recommend putting the butyl tape roll in the freezer for a while before using it, because it is less messy to work with and it unrolls easier than when it is warm.

[Minics04]

I used Proflex RV Clear Sealant.

[Capebuild]

Thanks all for the help/responses and suggestions.
I think I'll wind up using tube caulk of some variety. I have 4 (or so) tubes of Proflex RV which I should probably not waste. If/when I run out I'll get the OSI clear.

John