1970 Dart First Restoration. Help Appreciated!

I have been blasting the problem areas with Black Diamond but was told to use stripper on the outside body. I picked up some rustoleum aircraft stripper. It takes about 3 coats to get down to primer. Is that normal? Is there something stronger I could use and buy at a store?
I used the aircraft stripper from Oreilly's (forget the name) then cover the stripper with plastic wrap (like from your kitchen). the stripper evaporates and it quits working before it can react with all the paint. once you cover it wait 30 minutes or so and it will peel off like butter.