Chemical strip and Prime or Sand and prime ?

So if you use a chemical stripper are the certain ones that affects the aluminum more than others?  We used the citri-strip because we were afraid of the reaction that occurs with other products, is this true or am I wrong?

Monabones I used a vibrator Sanders. Just rough up the paint and then clean it up with paint thinner. Makes a good base for paint.

I think that unless you are trying to remove all of the paint (as if to polish the aluminum)...it is not necessary to "strip" off all of the old paint. Our's had very faded original paint. I just wet sanded with various grit sandpaper ( by hand ) finishing with 220 grit. I figured that if after 50 + years there was still paint attached, I might as well just paint right over it. I did use sanding primer. Almost 5 years later there has been fading (red is notorious for that) but the paint is still intact. It all depends on what your expectations are. We just wanted a fresh, clean look...not showroom shiny. We camp in places where we expect scratches and dings to happen.