Wet sand and clear coat over Dupont Centari

[68charger440]

I painted my Charger close to 20 years ago with Dupont Centari Acrylic Enamel, I also used Dupont catalyst/hardener and Dupont warm weather reducer.  After all these years it needs some touch up, but the car is extemely straight and so I don't want to strip it.  I WOULD LIKE TO WET SAND IT AND GIVE THE WHOLE CAR A COAT of clear coat after fixing the chips and a ding on the hood from my air cleaner on one of my more stupid days.  Can anyone tell me what grit to wet sand with that will give enough bite for the clear coat without leaving visable scratch marks after a few coats of clear?  Also what activator should I use and will my Dupont warm weather reducer work with whatever you recommend. 
FYI... Dupont/Axalta does not make anything anymore to clear over Acrylic Enamel.  Got that info from them direct today.

Thanks
Jim

[hemi-hampton]

I painted my Charger close to 20 years ago with Dupont Centari Acrylic Enamel, I also used Dupont catalyst/hardener and Dupont warm weather reducer.  After all these years it needs some touch up, but the car is extemely straight and so I don't want to strip it.  I WOULD LIKE TO WET SAND IT AND GIVE THE WHOLE CAR A COAT of clear coat after fixing the chips and a ding on the hood from my air cleaner on one of my more stupid days.  Can anyone tell me what grit to wet sand with that will give enough bite for the clear coat without leaving visable scratch marks after a few coats of clear?  Also what activator should I use and will my Dupont warm weather reducer work with whatever you recommend. 
FYI... Dupont/Axalta does not make anything anymore to clear over Acrylic Enamel.  Got that info from them direct today.

Thanks
Jim

Curious what they use to make to clear over acrylic Enamel? And what made it so special?

[68charger440]

Not sure what they used to make the Centari activator/hardener  special, but I have been told by many sources that the chemistry of the various paint manufacturers can ruin the paint if you mix manufacturers additives with other manufacturers paint. It may or may not work depending on what you are mixing from which manufacturers. I have seen this for myself on this project. I tried using Omni hardener with my Centari paint on a test spot on the Charger. It sprayed on fine and looked great, but even after a week of drying in 90 degree weather the newly sprayed test spot crinkled up when I tried to put some clear urethane on top of the new paint on that test spot, but where I overlapped the urethane onto the old Centari that was activated with the proper Dupont 793s activator/hardener, the old paint did not crinkle at all.  So something is different, I just don't know what.

[hemi-hampton]

Yes, after painting cars for over 35 years I'm well aware of it being a big no no mixing different paint products together. The impression I got was you were saying they once had a clear specifically made for clearing over acrylic enamel. I've never heard of such a thing. One if you wanta use a single stage enamel then there is no need to even use a clear at all. Unless it's metallic & you want to wet sand & rub that. What I want to know is why couldn't you use any clear that Dupont/Axalta makes now today to clear over it. Another Question, how do you plan on fixing these chips & ding on hood? with the original Dupont Centari Acrylic Enamel you used 20 years ago? if your going to take the time to Clear entire car then just repaint entire car same color in Dupont/Axalta Urethane single stage.    LEON.

[68charger440]

I am afraid the urethane will lift and crinkle the old paint.  That is why I was looking for something that would not crinkle the old stuff, but when I tried a little spot of urethane on top of where I fixed a chip it crinkled the newly sprayed AE even after drying for days.  That may be because I used the wrong hardener on the AE.    I am open to whatever you think would work best, I just don't want to ruin the whole paint job because it is otherwise perfectly straight and looks great.  If I go urethane do I have to sand with 600 to give it bite?  I am not a car painter, but a commercial painter that had to use some automotive finishes over the last forty plus years.  So I can spray anything, but all of the prep, mixing of products etc for cars is a bit out of my comfort zone.  When I painted it originally the acrylic enamel went on like glass and was flawless. I was hoping to just redo the hood and the couple of chips and buffing them out, but Iam sure you know this stuff worlds better than me so maybe the urethane is the answer.  The Centari is still good and sprayed fine on a test panel.  I just heard horror stories about urethane over AE not adhering well when the AE is years old.  If you are confident of the best way to go I am all ears.

Thanks
Jim

[68charger440]

Also, Dupont/Axalto doesn't make any clear coat that they will recommend putting over AE so the same color urethane might be my only option.  I sure do appreciate your suggestions, and I'll probably do what you would do with your own car so give me your final answer and I will probably go with it.
Thanks again.

[hemi-hampton]

As far as I remember from Spraying lots of Centari in the 80's is it would not lift unless you did not use Hardener. Back then, in the 80's a gallon of Centari Acrylic Enamel was only $20. BUT, The pint of Hardener needed for it was $20. which automatically doubled the price. Since Hardener was optional & not mandatory many, or most tightwads would not buy the Hardener. In that case the Centari would definatley lift if no hardener was used. if hardener was used you would have no problem repainting. Another big problem is it could of lift because you bought cheap products. PPG'S OMNI or Shop Line or Limco or any of those hundreds of other cheap products will lift because they are garbage. If you didn't use hardener on it originally then it would all need to be striped. LEON.

P.S. I'm sure lots of people in here will say they use the cheap stuff all the time & it works great & they never have a problem. I disagree 100%.

[69HemiBee]

As an added precaution you might want to, after prepping your old clear, top coat it with DuPont/Axalta 222s mid coat adhesion promoter. Try a small spot first but it should not attack paint that old.

[68charger440]

Well here it is with Nason high solids Clear coat on top of decades old Dupont Centari Acrylic enamel. I wet sanded the old red Dupont with 800 grit to give it bite, then 2 coats of the clearcoat and then cut and polished the clear since I did it all in my home garage and got a few bits of dust that settled on it when it was wet. It came out great and since it was perfectly straight to begin with it sure was easier than stripping it to bare metal.

[hemi-hampton]

So, I'm guessing you had no lifting problems, if not, congrats Looks good from the Pics LEON.

[68charger440]

I bought the correct hardener for the old Centari and then re-did the couple of chips and hood ding with the original Centari. I let that dry out for a week just to be sure it had time to really dry out good, wet sanded it and then I tested one of the new spots with the Nason and no lifting so I did the whole car. 
Only time will tell how long it lasts but since it is always garaged unless I am out cruising I am hoping to not have any problems.  I'll let you know if I do.