It is one thing to summarize; another to carry out. First, the 0.375" thick tube sheets are machined or ground for the relief bevel with @ 0.90" land. The sheet is then tack welded in place with short tacks. Then a 7018 (a low hydrogen rod) root pass is welded in. (Our shop utilizes a 7018 root pass procedure in order to avoid root cracking, a common problem with 6010 wire on circular or pipe weldments.) The root pass is almost ground out with a 4.5" grinder to ensure complete penetration and to ensure that there are no inclusions in the metal. Following passes are laid in and ground out as needed. I skipped around to minimize bowing and distortion, but it is hard to avoid.
Here is an image off the web. It is of a MIG weld but it is still illustrative. It shows a root pass, the pass ground down to eliminate inclusions and the "keyhole" at the arc, a mark of good penetration.
