Surface prep before painting

[Pchrosto]

Hi all!

I am trying to get more paint time in on different projects, and I have a question (or two). I am repainting my 1987 Fiero GT piece by piece because I can take it apart and spray it in my booth in my basement. I am using the HOK paint system and do not deviate from what is said in the tech manuals. I stay with the HOK line exclusively.

The question is this (and not just relating to the Fiero): the tech manual states that if the original facory finish is on the car, you can use that as the base for the HOK paint job. But ideally, the manual also states that the overall paint thickness can't be too great or the new paint may crack or delaminate. So, how far down do you go through the factory finish before it is okay to begin the new project? Through the clear? Through the base? Through the factory sealer?

On the Fiero, I am sanding through the factory clear and just barely through the base coat so that the black surface or sealer is starting to show through. Then I go the whole HOK route: primer, sealer, basecoat, clear coat. I've got the hood ready for final buffing, and it appears to have turned out okay. So, am I going down too deep on the factory finish? I'd like to know of the best starting point so I don't waste any more prep time than I have to.

Thanks!

Pete

 

[TAZ]

If the original paint is in good condition, all you need to do is normal prep. Then you can apply the new sealer, base, clear.
If the original paint is starting to show signs of where the clear is starting to peel off the base because of over the years it has gotten then, then you should at least remove all the clear.

 

[Pchrosto]

So, the original factory finish paint thickness along with the new HOK paint thickness won't present a problem?

 

[TAZ]

Not at all! You'll be fine as long as it does have 1 factory paint job, and it was in good condition.

 

[Pchrosto]

Thanks Taz, I appreciate it! That really puts my mind at ease with proceeding on this project.

I did see something on a custom car program the other day that made me pause; they just took a stock Mercedes, scuffed the clear coat that was over the red paint, and immediately applied black paint to the clear coat. Is that type of paint job acceptable?

Pete

 

[TAZ]

Sure, you can do that. Although just 'scuffing' the paint is not good practice as you really need to sand it flat and sand until all spots are 'dull'.
No problem painting over the existing base coat...again, as long as there were no issues with the previous paint job (i.e clear peeling, wrinkling, a lot of chips...)