This heat source has typically been an oxy acetylene gas torch, but brazing can also be performed using a MIG (metal inert gas) welder.
The process is probably not well known, but it can come in handy for a range of welding jobs in the farm workshop.
MIG brazing has been used in the automotive manufacturing industry for several years to join high strength steels using a low heat-input process.
View the PDF report here: Mastering MIG brazing basics