[TowerTalk] welding aluminum

[Bob Tabke]

I am building a 6m H-frame (33'x40') and need to connect two 4.5 inch 
pieces of T6 aluminum pipe as well as two sections of 3" al tube. I have 
an al welder. But I am wondering if anyone has experience with welding 
T6 aluminum causing a loss in strength due to lessening the temper? The 
joints will have cradles on either side to reinforce the joint...

Thanks,

Bob, N7IP