Welding aluminum with oxy-propane is not a big deal.

You need a fuel reg to fit the propane can and some "T" grade hoses that do not deteriorate when exposed to propane, natgas, chemtane, chemolene, propylene etc. "alt fuel" gases.

You can use an oxy-fuel torch and tips and there is no explosive danger mixing one fuel gas with another through the same hose as there is with hydrogen.

Here are special "alt fuel" propane tips available for the Meco Midget. Instead of one central flame there is a "ring of fire" around a smaller central flame, giving more BTU's into the melt.

Using the same sized acet tip or one size larger works well, if you are already welding aluminum with O/A.

Use a really good flux as the propane leaves a bit of smut that the flux is required to carry off during the weld. I use our Super Premium AGW flux. (AGW= aluminum gas welding)

Bear in mind that finding the neutral flame is difficult with O/P as there is no defined sharpness of the flame achieved by adding oxygen. The flame cone either gets longer or shorter by twiddling the knobs, so I just do a weld test on an aluminum coupon while adjusting the flame.

Flux the rod and maybe also the top surface of your joint.

Have at it and see what you get. Torch handling, angle to the metal, cone distance from the work are all the same as O/A.

You will have a larger noisier flame for the same weld on the same material as you will with O/A,using the same torch and tip, as the O/P has less thermal output than does the O/A, because acetylene is a triple-bonded hydrocarbon and the rest of the fuel gases are only double-bonded. Each bond breaks during combustion to release a certain amount of thermal energy, so you have 2/3 energy compared to 3/3 energy output.

Click on images to view larger.