Brent, Molybdenum anti-seize works fine on the threads with a cap when welding. R/Jay Resepectfully, Jay K. Jeffries Andros Is., Bahamas Save the whales, collect the whole set. From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent Hartwig Hi Frank, I've noticed of late that all the propane tanks I've been looking at use couplings for there thru hulls. They must have the welding distortion issues worked out. Perhaps much the same way as my relative plans to do it next time, by just installing two treaded steel plugs before welding to limit distortion, and keep the dingle balls out. I'm not sure what would be the best way to deal with the SS gulling issue, with all the heat that will be on those threads you might not be able to use Teflon or moly grease for the temporary plugs. Perhaps some thing like baby powder would do the trick? Cheers, Szybowski |