Is PPG the same as DuPont and I don't know it?

no, PPG is not DuPont altho DP402 is a very good product as is all PPG stuff you should not mix brand names as each brand is made to work together.Stick with all DuPont undercoats if you are using their paint....

Dupont and PPG are two seperate companies. The DP402 is a catalyst for the DP series of catalytic non-sanding primer/sealer. DP402 is not the primer, it is just part of a two part system.

Please take this advice seriously: You need to go with one paint system and stay within it if you want to safely paint your car without fear of non-compatible materials. If you mix Dupont and PPG or Sikens or RM or whatever, one of the paints may cause the other to bubble up or not adhere properly or even not dry. So pick Dupont or PPG and use only their other products starting with the sealer, sanding primers and top coats. You really don't want to have to sand off a whole coat of something or even more to correct a compatibility mistake. I am assuming your paint dealer is guiding you and It all may work out fine if you mix brands, but why take the chance??

I just talked to the guy in the auto body supply shop. He said he'll see if he has the DuPont products I need. If not, he's going to give me my money back. Why are these guys like this? Granted, I did not check the stuff before leaving the store. But I specifically said that I was using DuPont Centari and that I wanted DuPont epoxy primer.