At 05:58 PM 3/30/2005 +0200, you wrote: >>When welding aluminum I always preheat the whole piece for flow and stress >>relief, but steel benefits from it as well; I think that the front part might >>fit in my oven - I'll have to measure. A pro welder I know has two ovens in >>his shop... >> >Right. Give me your adress, i send it to you! He's the flawless welder, not me! I used to have a Miller Econo-TIG, but now just a gas MIG... >What degrees celcius do you warm it up (a color would also be fine), and does >it help to heat it up after welding is done? He would heat it to ~500F, not really even dull red, just for expansion relief and faster arc penetration - not softening. >Will the tandem be unsafe because of MIG welding? I heard that CroMo >degenerates (or somethign) when heated up? I think the CroMo requires better matching wire and care not to overheat badly. You might also find a noticeable difference in melting temps if joining different steels. I just use mild steel wire and over build the joints on projects. I also have a little brazing kit which is fine for many joints and does not cause heat warping. Ray