Hi, I'm trying to help my friend repair his universal M1 Carbine that had the slide assembly break. The part was two pieces, flush, with a spot weld between the two. I tried using a MAPP torch and some silver solder to repair it, but the second it cooled, the metal flexed and broke the joint. I'm new to this and not sure how to proceede with my limited tooling. How would one join two small pieces without creating a seam and keeping it flush. I will try to post pictures in the comments.