Never used this stuff nor have I ever welded anything Not that type of dude Has anyone used it Can it really be used to butt joint How strong will that joint be? This will be used to repair to a clamping mechanism so it must withstand some minor Squeezing? probably less than .5mm I would take the ends to be welded and file away on each to create a V shape between the two and then fill in the V with the weld material. Perhaps not exactly a butt joint by definition but this has to be stronger Then grind, sand and polish to match the original shape. I'd rather not have a blob of material overlapping for "extra strength"