Originally Posted by SteelTherapy
With pre and post heat, will a MAP gas torch be good enough?
Imo no it isn't. Letting it cool completely then reheating is very important. As it cools it will have uneven stresses throughout the weld. You have to get it hot enough to relieve the stress which is around 1200 degrees. You will never get that with a map gas torch. It doesn't need to be done immediatly just before you put the weld into use. You can weld it up and bring it to someone's house that has a real torch.