I read the P sheet and it says to top coat with paint or a 2 part primer within 7 days while it is still in the window or it must be scuffed and retoped with more DP.
I asked the paint store if after that window, if it would be ok to scuf and top coat with 2K primer with out the coat of DP. They said it should be ok even though I have broken the rules.
Reason for wanting to skip the re-coat of DP is it is very costly.
I will be blasting some "Donner panels" and using the DP to keep them for futher use down the line.
I know you can just top coat E coated panels with a light sand or scuffing so should the DP be that much differant?
I also see this being a problem while working on the car
{ie} Say ya get the engine bay ready, coat it with DP and then move one to another section the same thing would happen

Why not just topcoat the DP with the 2K then store them?
I would be willing to bet that scuffing the DP just prior to the 2K, in the future, would be fine, just as your paint shop said.
PPG does have a good tech line--I think the number is on the Tech (p) sheets? if not its on the net, Ask them. I got soem realy good advice from them regarding all the different hardeners that can be used with DCC Concept.

Yea I hear ya Kevin, I've never done it so I can't help.

But I know what your asking, this has always caused me to start painting my work trucks after sand blasting and don't stop till I'm done with finish colors. Usally takes a couple days but I get em done with no sanding, scuffing and no recoating$$.

If were me I'd leave everything bare and blast everything right before paint. But I know not everyone has a blaster sitting around like I do.

It's the same thing with etch primer too. PITA

The 7 day window has to do with the ability of the top coat to have a chemical bond to the DPLF.After the 7 days you must scuff and then it is a mechanical bond.

DP90 is the "final color" for half my cars...

Heres some SEM Hot Rod black.

Your post got high jacked!

E-coat stands for Electro coat or Electrodispositioncoating which is the application method not so much the product.

http://www.clearclad.com/clearclad_resources/ecoat.htm

There are however epoxy based e-coats. But not all epoxies are created equal therefore they will all have different qualities. Similar but different. So yeah they are different.

As for what to do since you have lost your chemical adhesion you will have to go for mechanical and thoroughly sand (read your primer tech sheet for grit recommendations) the panels and apply your primer. All should be okay from there. Do however be careful of cut troughs. For engine compartments, door jambs, trunks etc. I would try to set myself up to apply two coats of epoxy and topcoat per recommendations. Fastest, easiest, durable and least costly in the long run!

Now on to the epoxy as a topcoat it will start to break down as it has no UV protectants built in. So when it starts to chalk up get ready to repaint. That is why DuPont makes a Hot Rod Black. It is a matted single stage that has UV protectants in it so it will hold up as a topcoat when applied properly. There are matting agents for single stage colors as well as clear coats. Just an FYI for those that were not aware.

Later,
Geno