On 3/29/2018 10:24 AM, Jim Wilkins wrote:
I just signed up for a blacksmithing class. The instructor isn't
averse to non-traditional methods and has MIG and acetylene in the
shop. What should I watch out for if I plan to hot forge a previously
arc welded joint? I could be welding high and low carbon steels
together.

-jsw



Most likely you would be welding for the purpose of making forge welding
go easier. The number one biggest thing is to get dirt, oil, mill
scale, and rust off the pieces before you start. You want clean steel
on steel surfaces, and then you would use flux to reduce oxidation, but
there are guys who claim with a properly setup forge with a reducing
flame you don't need flux. Even for multi layer hammer forged damascus.

Acetylene can be used for "Spot" heat treating where you can harden one
area of a part while leaving the rest soft(er).

I am sure there is a lot more. I'm just an armchair blacksmith. LOL.