Primer blocking question

[fireguyfire]

Just about ready to shoot the colour on my 73 challenger.
So far I gave the bare metal 1 coat of epoxy, then did my body work,then another coat of epoxy followed by a good coat of high build.
I blocked the high build with 180 and the body work is real good.
I then shot another coat of high build (hoping my last) and just blocked it with 400.

The result is 99% excellent, but there are 5 or 6 small spots, mostly on door or trunk lid edges where I went through to the metal; again you have to really look close to notice.
My question is, how should I deal with these few spots? The car certainly doesn't need another full coat of high build; that would be a huge waste.
Can I just spot prime these spots with a detail gun?
I also saw on YouTube a guy who just hit his similar spots with small amounts of epoxy to seal them up, then sprayed the colour on the entire car once the epoxy on those few spots had flashed.
What would you experienced paint guys and gals suggest I do?

[fireguyfire]

I also saw in a auto painting book that the author suggests after all the priming and blocking, and when you are ready to shoot the colour to hit the car with a coat of epoxy to seal it and then once that flashes, to paint the colour.
This method would solve my small burn through issues.

[Marty]

I also saw in a auto painting book that the author suggests after all the priming and blocking, and when you are ready to shoot the colour to hit the car with a coat of epoxy to seal it and then once that flashes, to paint the colour.
This method would solve my small burn through issues.

That's the ticket. 

[JS29]

Primer sealer is always a good idea. the epoxy primer can be reduced to be used as a sealer. read the instructions and procedures and you will be fine. The system i use is made by Exalta Formerly Du-Pont. It is caller value shade. You find the # on the can of base, Mix that color and spray. You have uniform color and you use less base coat. Same go's for single stage, you can get the job done with less paint product.     

[Rich G.]

I agree, one coat of primer sealer and then color. Make everything uniform and the best part is you don't have to sand it!

[fireguyfire]

Thanks for the advice gents.
I looked at the technical data sheets that cane with my epoxy primer, and it mentions nothing about thinking for use as a primer/sealer; just regular use ratio of 4:1:1.

Anyone got a suggestion how to thin for sealer use?

[JS29]

What brand of epoxy have you got? 

[1 Wild R/T]

I'm surprised no one else has mentioned it but the jump from 180 to 400 is a pretty big step & I'd be surprised if there isn't some 180 scratches hiding waiting for color to be laid down before they become visible....

Typically from 180 you step to 240 then 320, 400 & possibly 500....

[fireguyfire]

I blocked the 1st coat with 180; then sprayed another coat of high build over that, then blocked the second coat of high build with 400; was slow but it is very slick.
I'm debating on taking it to 600 before the sealer coat

[7E-Bodies]

Good stuff here. I'm about to enter this stage as well. Hoping @Cuda Cody chimes in as well since I'm following his written protocol through the whole project. I guess my concern about adding a final coat of epoxy before color is covering a nicely sanded surface with a slightly rougher surface of epoxy.

Kevin

[Cuda Cody]

PPG DP makes a great sealer and will solve your bare metal issue.  400 dry or 600 wet is good.

https://www.e-bodies.org/how-to-paint-a-show-car-step-by-step-guide/

Just mix it slightly different when using it as a sealer.   Mix at the 2 to 1 to .5 blend ratio will result in a 5.0 VOC sealer.

https://www.e-bodies.org/Resources/Mopar_How_To/p196_DP_epoxy_primer_ppg_dplf_product_sheet_196_dp40_dp48_dp50_dp74_dp90.pdf

[Rich G.]

If you used a guide coat when you did your final sanding you would know if you left any sanding scratches. The primer sealer is very thin that's why you can get away from sanding. I'm just finishing up a cuda using Cody's painting tips.

[fireguyfire]

Yup; used a guidecoat

[tparker]

Just a side question. What exactly is a sealer, or why is it called that? When I think of a sealer, I think of it being sealed off. If I remember correctly my primer said just reduce more and it is now a sealer. To me it is just "watered" down primer. How is it sealing where the primer wouldn't?  Just curious on the details.

[fireguyfire]

I'm using BASF Limco LR20 epoxy primer; it's a 4:1:1 mix ratio so I'm not sure how I would thin it out to use as a seal coat