TOPIC: Silicon calk and aluminum

Silicon calk and aluminum
Today at 18:37:01 Quote Modify Remove
Being that I have a friend (That is also very good customer) that has a hobby of restoring Airstream trailers. I went to one of their "how to and swap meets" this weekend. I was there mainly to give pointers on how to install an AC system in the pre 60s trailers without it being seen and no major cutting on the trailer.

Well one of the speakers was from Dow Chem, and his main focus was about the use of silicon calk on aluminum.

Well the short of it is to NEVER use silicon calk on aluminum that has acetic acid in it (nearly all silicon calk has acetic acid in them) for it will etch and eat away at the aluminum.

After a few years the caulk will break loose from the aluminum and if the aluminum is thin (as on Airstreams) it will eat holes through it

Thanks for the great info. That is something very good to find out as many people use it on everthing. Skip.

The acetic acid (vinegar odor you get from the tube) is there to inhibit cure, it disapears once the silicone is cured. They do make non acetic cure silicones. I'm pretty sure most of the colored loctite varieties for engine sealing are non acetic, the blue red copper and silver don't really smell like vinegar so maybe check those varieties out. Not all silicones use the same chemical curing mechanism.
Also try "Goop", that stuff is unbelievable! I was a doubter looking at how it comes out of the tube but, wow that stuff sticks (silicone is marginal) and it is tough and flexible, dries quick and seems to hold up ok underwater for few days at a time.
It is a solvent base that evaporates letting the stuff cure.
Randy