Sealants for Automotive Applications
I have noticed a number of references to use of silicone sealants in various build threads. This raises a question for me.
A number of years ago, I spent some time hanging out at an auto body shop. The owner, Cliff, is a meticulous guy. One of the things he told me is that he does not allow silicone-based sealants anywhere on his property. He told me that it is nearly impossible to completely remove silicone from metal when doing paint prep, and that even trace amounts of residual silicone will cause the new paint to fish eye.
I used to be in the maritime world, and in that context we used a lot of polyurethane- and polysulfide-based sealants, neither of which cause issues with paint. The best polyurethane sealant that I know of is 3M 5200, which has a reputation for lasting longer than the boat. The only downside to polyurethane sealant that I am aware of is that its adhesive properties are so tenacious that it is functionally impossible to disassemble parts thusly sealed together. Life-Caulk is a quality polysulfide sealant that sticks to anything. The only downside to polysulfide is that it will cause most plastics to become brittle over time.
So—I am wondering what thoughts people have regarding good automotive sealants. Silicone? What about paint issues? Polyurethane? What about potential future disassembly? Polysulfide? What about its incompatibility with plastics?
OMG, the Silver Streak is Sold!
2006 SMB EB45ish.
5.4L, QuadVan 4x4
Ready to Rumble!