Cutting, grinding and hitting with the flapper disk has all the tube ends fish mouthed and aligning perfectly. The longerons are jigged in place and plumbing pipe straps clamp all the tubes securely to the table. These are loosened off to slide some steel sheet to act as a heat shield under the joint to be welded and then re-tightened. The bench still catches fire but at times but doesn't become a blazing inferno. I tack welded before going back over the joints and finishing them off.