Join Date: Dec 2015
Location: The Very Tip of Lake Michigan
I have bent many, many 1/2', 5/8" and 3/4" mild steel rods with a simple propane torch. I can't figure why some you think it can't be done. Maybe if you were making a hundred of them I might suggest more heat, but for a few? Go for it with what you have, assuming you have a common plumbers torch. Steel melts at 2750F; a common propane torch will do about 1970F. A yellow cylinder of MAPP will increase that to around2100F. Either gas will do for bending and forming. I would not consider a weed burner since the flame is too spread out and thus not really hot enough (more of an orange/ yellow flame).
It takes a little bit of time to get your rod to cherry red, but it still won't take any longer than five to seven minutes per bend. Have your radius form ready, chuck your rod in a vice (I mark my heat zone with soapstone), fire the torch up to max and keep the flame moving along and around your heat/ bend zone. The hottest part of a torch flame is at the point where dark blue meets light blue flame. All you need is a dull orange/red color, but make sure the color is in the entire heat zone before attempting a bend. Also keep the heat zone away from the vice jaws to minimize heat sinking.
Welding gloves come in handy unless you are bending long rods and can hold the very ends. When finished bending I toss my rods in a bucket of water or throw a soaking rag on the rod to quickly quench it.
Remember to overbend a slight bit as mild steel will open up a bit while cooling.
Another $000,000,000.02 worth of advice,