Tig welding a cracked frame

(S.F. Calif.)

We have a cement powder truck trailer with a cracked frame, 1/2" aluminum, about an 8" vertical crack through the frame. Can you give me any tips on preparing this to be welded. How much do I want to v it out? Should I v out one side and weld it and then v it out to the weld on the other side and weld it? Should I pre heat the area? Any other tips also would be appreciated. Thank you.

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you are on the right track.

v it out, preheat , weld, then v out the other side, preheat, and weld.

I would say you want to v the joint close to halfway from each side give or take 1/8"

if it was a full strength joint before it broke, it needs the full cross sectional thickness.