Here is the 80cuft oxygen tank with the disposable Mapp gas. The one drawback of this system is that the Mapp gas (and propane, when propane tanks are used) dissolve some of the rubber in the fuel hose since it's an acetylene hose and propane is damaging to it.
I began with a typical propane or Mapp gas torch head. These are meant to be screwed onto the small disposable gas tanks.
First I unscrewed the "neck" part of the torch assembly from the valve body. It was very tight and I think it had "Locktight" adhesive on it. After it was unscrewed I cut the torch tip off leaving only about 1" of the bottom portion of the neck (the part with the threads). The torch tip can be discarded (or tossed into the brass scrap bin).
The short section of the neck that I cut was soldered to a section of a brass fitting that has threads that match the acetylene hose. This formed the adapter so the Mapp gas tank can be connected to the acetylene hose.
Here is a crude version of an adapter. Instead of soldering the brass fittings directly together like in the adapter above I soldered them to a piece of copper tube with caps on the ends. This was the first version I made. The valve body was from a very old torch and had a bad leak so I discarded it for the newer one detailed on this page.
Here the adapter fitting is screwed back into the valve body and all is screwed onto the Mapp gas tank. At this point it is ready for the hose to be installed.
Here is the flame from the Mapp gas conversion. It is not as intense as an acetylene flame but it is plenty hot enough to heat steel. With this conversion I can also use propane for a oxy-propane torch if I want. But with propane the torch is harder to adjust to a stable flame. The propane flame tends to blow out when adjusting it until the torch tip is warmed up a bit.
Here is a store-bought miniature oxy-Mapp torch set. The small flame is very hot but the disposable oxygen tanks only last about 15 minutes.
For those interested here is a photo of the cart I built for the tank. Welded together from various pieces of steel, mostly rebar.
After about 1.5 years of good use the valve for the disposable Mapp gas tank failed and I couldn't use the torch with Mapp gas anymore. So here's the modified cart making it officially an oxy-propane rig. It looks bizarre but works great. This bigger propane tank works better than the disposable ones. I intend to stay with this system since replacing those disposable gas tanks gets expensive. Unfortunately I can't find a supplier of large tanks of Mapp gas and I don't want to use acetylene so oxy-propane it'll be. Now I plan to replace the cutting torch with a heating tip and use this just as a heating torch since I have something else for cutting.