Quote Originally Posted by Giovanni89 View Post
Oxy-Acetylene is still widely used for chromoly tubing frames in aviation and motorsports. I doubt this is chromoly, but The extra heat put into the tubing by torch welding allows it to cool more slowly and anneal the weld. you can also use dead soft filler rods. Lots of weld failures in high vibration environments occur because the weld has 2-3 times the tensile strength of the base metal. This creates a stress riser where the edge of the weld meets the base metal (typically where you see failure)
Giovanni

For welding -- Our USNavy required us to know the base metal material & then choose the specific filler metal + they often used documents called "Welding Procedures" that called out the filler metal, weld type & joint types... The tensile strength of the filler wire/welding rod was often similar to the base metal OR a little higher psi (never lower that I recall)...

For brazing -- Oxy-Fuel torch braze welding a socket type joint makes a stronger joint; not sure how it might soften the bike frame... This is often called silver brazing, it's 800F so it's a weld... Try breaking these socket joints; almost cannot, must destroy the item to do so... This is because the area bonded is much larger than external weld joints... Silver brazed socket joints are difficult to perform with good bond (80%+) because unlike regular weld joints, you cannot see the weld metal flowing and bonding inside the socket...

Stay Safe