[quote="MBounds"So what is a T6 temper? T6 tempering involves two steps—solution heat treating and aging..[/quote]
Yes, I did a bunch of research, so I could at least discuss it intelligently with the fabricating shop.
Practically, I don't think there is an economical way to re-temper/age such a large piece.
However, the aircraft home builders do repairs. By sourcing some of the certified fixes, it seems they insert a tube inside the break,(cut at 30*), and use rosette welds, and along the seams to obtain the original strength. They can also weld patches over the tube, if a smooth finish is not important.
John, Sabres, with regards to the welds cracking, that is almost a given with 6061 IF YOU TRY TO WELD AUTOGENOUSLY. You must use a filler wire, most commonly 4043. That dilutes the weld puddle & gives satisfactory results.
The other major thing is degreasing, use acetone or toluene, not alcohol.
I believe this tubing is anodized, & that is the 3rd major consideration. The anodizing MUST BE PHYSICALLY REMOVED, by sanding or grinding.
Also make sure your welder uses AC. The alternating current blast away any left over anodizing.
This site has some very good Intelhttp://www.thefabricator.com/article/al ... s-for-gmaw