Mps 450 frame

[cryzsurfer]

It looks like that crack was caused by the shrinkage of the TIG weld when rewelding the Y. It's a little thin as in definite undercut in that area by the corner and there could also have been a nice small crater crack already hidden there as it looks like an original MIG weld if you look at the inside weld. TIG will pull considerably more than MIG and with such a short welding area and the speeds the production welds are done it was destined to fail. It would be preferable (not to sound like a Monday morning quarterback) to make sure all old welds are filed or high speed carbided away before refitting the joint. When we have to redo a weld joint we start fresh such as cutting it away from the heat affected zone and adding material on the new piece to make up the difference. Especially if there's a high stress area or NDT like X-ray or penetrant testing required.
Craigus