Correct Sealer Primer - Urethane vs Epoxy (for C1 restoration)?

[Jill J.]

Hi there.

I'm currently in the "paint" phase for my C1 (59) body / components. I've applied filler primer for the 2nd time and am wet sanding in preparation for the sealer primer phase. I plan to purchase the Acrylic Lacquer (PPG) from TCP Global as my color coat.

When I went to the paint store yesterday to purchase more filler primer, I asked what they recommended for the sealer primer after mentioning I would be painting lacquer as my color coat. I also mentioned I would like to continue using PPG products throughout so I don't mix brands.

He recommended either urethane (which I purchased) or epoxy as the sealer coat. Would you recommend one over the other (urethane vs epoxy) or will they both prep the surface appropriately prior to applying my color coat?

I've put so much work into this project so far and want to make sure everything will lay down without too many issues.

Thanks in advance for your assistance.


Jill, 59140

[Jim D.]

Re: Correct Sealer Primer - Urethane vs Epoxy (for C1 restoration)?

Everyone has their own way of doing things but I prefer to seal the bare fiberglass with epoxy primer prior to any body work and then, prior to painting, sealing again with a reduced coat of epoxy. I use SPI products.

[Mark E.]

Re: Correct Sealer Primer - Urethane vs Epoxy (for C1 restoration)?

Jill,

Paint technology is continuously changing, so my knowledge is dated. But when I prep a car, I ask the retailer for the product spec sheets. They describe when and how to use the product, surface compatibility (e.g. figerglass), surface preparation, and which products are compatible. This is probably also available on the manufacturer's website. For specific questions, most major manufacturers have a customer support line you can contact directly.

You may find that more than one primer-surfacer will work, and you'll need to weigh the pros and cons for yourself.

For fiberglass, I learned that letting the primer-surfacer age prior to prepping for paint helps minimize sand-scratch swelling and shrinkage. On one Corvette paint job, I had the luxury of letting the p-s age nine months before painting. 15 years later, the lacquer and body work still look great with no cracking. You may not have nine months, but even a few weeks will help a lot.

[Domenic T.]

Re: Correct Sealer Primer - Urethane vs Epoxy (for C1 restoration)?

Jim,
Exactly the way I have done it. Had some old glass parts (not vette) that were in the sun forever and looked like they were growing hair. Thought about getting new ones till I priced them. Sanded and epoxy primed, repeated and painted. They look new. What an improvement compared to the old primers we had to use that eventually shrank and allowed the flaws to show Months later.

Dom

Dom

[Rich P.]

Re: Correct Sealer Primer - Urethane vs Epoxy (for C1 restoration)?

Every Corvette I've painted since the mid 80's I have used PPG DP sealer. I wasn't too thrilled when they came out with the LEAD free DP in the 90's but still continued to use it. Never had a problem with bleed through lifting or anything always worked out great.

And by sealer coat just to clarify this is once all body work has been done, several coats of sprayable filler and urethane primer has been applied and sanded completely, final sanding wiped down ready for paint the epoxy was reduced out to the specified viscosity for sealing. 2 ig
Medium wet coats were applied then half an hour later the paint was applied.