Our friends at Alumaloy (Low temp alum. repair and welding) have come up with two new products: one for steel and one for cast iron.
Both are applied with a propane or Mapp gas torch and are said to melt at 500 deg. F.
I wouldn't recommend one of these for a structural repair; but, they might be useful for the repair of of stripped threads. Drill out and retap. I don't know - I've used alumaloy to fix a couple of aluminum parts and it worked just like they advertise. I can say a pound and a half of the sticks will last you about 50 years.
I was suprised because I have seen the infomercial for aluminum a couple of times; but, I have never seen the steel and cast products advertised.
You can get more info on their web site: Alumaloy.com