If this propane torch will get the metal hot enough it should braze another way is to get 2 car batteries (12 volt) and wire them up for 24 volt and use an arc welding rod but you would need a welding helmet.
I've never heard of welding with Propaine but have heard of cutting 1 inch plate with Propane and Oxy.
Propane will solder and a high intensity torch will Braze.
