Welding stress fracture in sheet metal
I have a 40 year old fender that has a small stress crack (3/4" long) on the lip that forms the inner edge for the hood opening. The crack is located where the fender is supported by the grill surround.
I would normally open up the crack and weld or braze a small piece of metal behind it to form a doubler to give added support to that area. But, due to its location I cannot increase the thickness of the metal.
What are my options for repair? First I thought that I should drill a small hole where the crack ends to keep it from traveling further.
I could MIG weld the crack, but I fear the concentrated heat will embrittle the metal next to the weld causing it to crack next to the repair.
I could Oxyacetylene weld the crack, thinking that the additional heat may anneal the area if cooled slowly thereby making the repair less likely to crack, but not sure.
I don't think I should braze the crack since the metal does not overlap; I am afraid the repair would not hold up.
Any thoughts? Thanks for your help!