For the moment I just want to weld rather thick (1-1,5mm) steel better than with MMA, no high perfs tubes in sight. This is just for fun, and I'll see later to eventually afford a TIG or Oxy to make lighter bikes or modify "good" bikes. A mix of them with MIG or MMA should sighly reduce total cost.

I was just surprised to see so little returns about it. Sure, framebuilders usualy look for good materials, but not for every projects (I think about cargo bikes, trikes, trailers...).