I need some help.
I am making a gigantic " weather vane type thing" (technical term?).
(some very thick material and I am slightly intimidated)
its made up of 4 arms coming out radially from a central bearing unit.
the arms are a mix of rectangular tubing (6" x 2" x 1/8" thick.) and
3/8" plate.the central unit is machined from a round of 12" 6061. it rotates on a hardened point with a delrin collar.
I need to stick the arms to the bearing. The two pieces mate on a flat groove vertically along the bearing.
____the question______
is the extra penetration gained from using Ar/He worth the extra dollars?, (we've been using straight Ar)
also, aside from oxy acetylene, what pre-heat methods have any of you had luck with?
any help would be much appreciated.