[pwrtrip75]

Why would you back purge them? They arent dairy, food, or medical grade and whats to say there was any burn through? I never back purge any headers I make and they arent 100% penetration....Why would you need to have that? Do they need to pass x-ray and meet california standards for earthquakes and building code? No. The weld size excedes the thickness of the material, so 100% penetration is not needed for any structual integrity. If the tubes crack it 99.999% happens around the weld...not the weld itself. So the material being used is what determines how it will hold up. Not if its welded to meet ASME specs. His welds might not be cosmetically perfect, but go over them with some finishing tools, die grinder, sander, and some polishing wheels they'd be pretty damn good. Just try not to remove to much of the weld.