440 Pistons, How F*cked am I
After all that ... if you just type "can you magnaflux aluminum parts" into google one of the first results is going to explain how to use the Magnaflux chem dye process on aluminum. It doesn't matter if you cap the M in magnaflux or not.
I know because I did it to avoid posting "hey you can't magna anything that's not ferrous" and being wrong.