Dried concrete on aluminum and paint

[crete]

I own a concrete pump truck that has a built in 2200 p.s.i. power washer on it. But I got some concrete build up on the aluminum diamond plate fenders,which I did'nt see. I have tried a turbo nozzle and it won't touch it. My question is this. What kind of p.s.i. would work with a 15 degree tip I will probably rent what ever size I need for a day. I also want to experiment somewhere on the paint where it won't show(trying not to peel the paint) Thanks Terry

[Mike B.]

I would not try cleaning the painted area with more pressure than 2000 psi. I have read of a cleaner that will remove dried concrete splatters, but don't remember were I saw it. try a masonry supply store. Good luck.