Will lacquer primer - over existing paint - cause any serious problems with a new paint job? Regular base coat/clear coat paint. I was told today that I need to sand off all the lacquer primer I have already put on my truck and re-prime with a urethane primer.
I know I've had cars painted, successfully, over the years - way before urethane primer came to be. Urethane may be better, but, I'm just looking for a decent driver quality paint job.

 

You don't have to sand it off, but with the benefits of the newer primers I wouldn't use lacquer.

 

Quote:

Originally Posted by cartmanea

You don't have to sand it off, but with the benefits of the newer primers I wouldn't use lacquer.

I wasn't aware of the newer type primers and I have already used lacquer. Would spraying an epoxy primer over the lacquer make for a better job or - just leave well enough alone and proceed with painting?

 

You should use a primer compatible with your top coat, even if you just apply two light coats over the existing primer.

 

I'm planning on a base coat/clear coat. Any suggestions? I'm new at this. Thanks for any help.

 

OK, here's my advice and like all free advice, it's worth what you paid. A paint job, and I mean ANY paint job is just like a house, it's only as good as the foundation, right? Whereas a good epoxy primer is like a concrete foundation, lacquer primer is like building your house on a pile of loose sand. There simply is no good reason to use it for anything other than a guidecoat when blocking out the epoxy. Epoxy is solid and waterproof, where lacquer is neither of those. Ever wonder how sanding scratches magically appear after you lay on the base? It's because the solvents in the base wet-out the lacquer primer and allow the primer to sink into the scratches in the filler, or other substrate. My method is to use epoxy, block it out, then use a catalyzed sealer, then base, then clear. Lots of painters don't use sealers, but that doesn't make it right. Sealer promotes adhesion and keeps those sanding scratches and repairs from ever showing. Ever see a painter lay out stripes or maybe a two-tone scheme and when they lift the tape off the base it peels off the base? You won't see that with a good catalyzed sealer. It seems that everyone has their own thoughts on what to use, but here's something that I feel cannot be overstated, (A) only paint over one paint job. If your car has never been repainted, and the paint is solid and not flaking, you should be safe to repaint over it, laying on epoxy, sealer, base and clear. Never try to get away with using the base directly over the old paint no matter how good it looks. (B) Always, always, always use one brand from start to finish. I know lots of painter who like to use brand A primer, brand B base and brand C clear. Those same painters seem to have a fair amount of comebacks, yet they insist it's not due to mixing and matching. Trust me, the chemists who design paint systems are much smarter than the guy down at the local shop. Always ask for a tech sheet with your product and follow it like your life depends on it, and if you don't understand a term on the sheet, make sure you ask the counter guy or at least get a phone number for the manufacturer. They typically want to see their product succeed and will offer free advice if you just ask. Good luck and don't hesitate to post any questions you have, there's lots of experienced guys on here.

 

Depends on the brand. My shop uses RM Diamont BC/CC. It will wrinkle and lift lacquer primer due to the harshness of the reducer. However I know painters that use DuPont BC/CC over lacquer primer without any problems. However having said that, if it was my truck, I wouldn't let lacquer primer anywhere near it. The only thing laquer is good for is clunkers that will be painted with acrylic enamel.
I agree with most of what Sand Man said except for the priming complete.(unless the original paint is not BC/CC) If this is just a paint job you only need to prime repaired areas. No need to prime the whole truck....... A good sealer though is imperative to a good paint job. It will save you a lot of headaches. The steps I would have taken are as follows.

1. Repair damaged areas and prime repaired areas and bare metal with epoxy primer.
2. Sand complete
3. Urethan primer over epoxy
4. Sand urethane primer
5. Seal complete
6. Paint wet-on-wet over sealer, using a ground coat if the primer color was drastically different from the paint.

By the way, is there any particular reason you are using Base Coat/ Clear Coat? If you are spraying a solid color, I would use polyurethane. (my personal favourite is RM's; "UNO")It will stand up to abuse a lot better than BC/CC, IMO. Good luck.

 

Well guys, while I really do appreciate your advice - it seems what you're telling me is for a situation where I have not already done what is done.
As it sits, my truck has had all body work done and is completely in lacquer primer. It is intended to be a "daily driver".
What I'm asking is - do I really need to remove the lacquer and re-prime? OR - can I spray an epoxy primer over the lacquer OR - can I just go ahead and paint it and be ok. I know lacquer primer alone was used for MANY years and is still used in some shops without problems. I am not discounting that there may be products now that are superior to lacquer, but - this is not going to be a show vehicle. I am simply wanting a nice looking driver truck.

 

I would sand it back off, but that's just my opinion.

 

"Never be afraid to try something new. Just remember, amateurs built the Ark, professionals built the Titanic..."

Well, I haven't gotten the answer I wanted - - so, I'm going to proceed with my "old school" lacquer primer.
I'll post photos later of the results.

Thanks for your efforts at converting me, but I guess I'm too old to change. "CHANGE" has nearly broken me these past 20 months - if you know what I mean.

 

If this is to be just a daily driver, why not spray it in acrylic enamel or something compatible with lacquer primer?

 

excellent thought and just may be the solution. Gonna talk it over with the fella that's gonna do the paint work.

THANKS

 

Agreed, if you aren't starting with a quality primer, don't waste money on the better top coats. What color will you be doing?

 

Gonna see how it all pans out - but not sure I agree that lacquer primer is "inferior quality" to others though. I have a 1952 F1 that was painted with lacquer primer and enamel paint (black) over 20 years ago and would put it up against most any done today with current methods.

I'm painting this truck (1972F100) in black/white.

 

I don't mean to sound condescending, and you are free to beleive anything you want, but I doubt there is anyone with any amount of painting experience at all that will tell you with a straight face that today's epoxys and today's base-clear systems are not many times better and many, many times more durable than any lacquer primer or enamel ever made. But it's your money, your time, your truck and your decision to use whatever is good enough in your eyes.