i have used ppg for many years and we did some test strips on aluminum with dp and ppg etch prime and dupont viraprime and acme etch lock. sorry i can not spell .BUT the ppg was last in hooking on the aluminun. the Dp and the etch prime this was over 15 years a go . i do not think it is any better .but i like there paint and clear so i would use acme etch lock and then sand it with red 3m pad and seal with dp 40 and go to k2 primer did many jobs this way and never had any paint fall off but there may be better stuff out ther now