Original Posted By: pietflyr(at)bellsouth.net
Jack=2Csorry for the confusion. If you MIG or TIG weld=2C the area must be preheated. If you are gas welding the preheating has already taken place before the area is hot enough to puddle. With MIG and TIG it=2C of course=2C puddles immediately without the surrounding area being preheated. In a nutshell no prehaeating with gas. Must preheat with MIG & TIG. 4130=2C that is. Also of importance is after welding 4130 must cool natually (slowly) to room temp to prevent cracking. What scares a lot of people away from gas welding is the perceived mystery and "art'' involved. while there is some art to keeping a good puddle going. most of it involves the science of proper flame=2C gas pressure=2C and tip size. Some good gas welding info can be found at www.tinmantech.com Another side benefit of gas welding... Good equipment is much cheaper.Doug DeverIn beautiful Stow Ohio