"Karl Townsend" remove .NOT wrote in
message ink.net...
I'll have yards and yard of places where the metal meets that I need to
seal. It needs to hold up to vibration and high air pressure. And be
paintable. What would you use?

When we built large air handlers for a convention center, we simply sent one
of our 'rats' (a young guy) down inside the duct with several boxes of Butyl
caulk and a air powered caulking gun. The stuff takes a couple of days to
set up strong, but it will withstand 8-10 psi across a 1/4" gap, Never EVER
loses its flexibility (out of sunlight), and sticks to ANYTHING.

LLoyd