Correct Primer Over Lacquer

[Mike B.]

Re: Correct Primer Over Lacquer

Just my opinion, but have you considered reshooting acrylic lacquer over the original paint? Then there won't be any incompatabilities with paint types or finish, and it preserves the OEM value. BC/CC is a great modern system and is highly durable, but it looks different than a single system such as acrylic lacquer (AL). And yes, AL is not as durable as BC/CC, but if your car is a Sunday driver than AL is just fine.

If you are going to paint AL, then a traditional high-build lacquer-based primer is best because the solvents will bite into the original paint. Then top coat with AL after wet sanding the primer (I am presuming the original paint is sound and not full of spider cracks). The beauty of lacquer is that it is forgiving (mistakes such as runs can be corrected easily) and it can be touched up at any time, but the trade off is that it has to be wet sanded and buffed after spraying to get the shine up. But it shines like nothing else if done right!

If you decide to go with BC/CC, then as the others suggest, it is best to strip the car. But if you use a solvent stripper, be sure to let all of the solvents evaporate before painting or air bubbles will permeate the paint later on. Murphy's law directs that they will appear in the most visible places just to aggravate you even more.

This link provides information about the various primer options. Navigate around the site to learn anything you need to know about painting including the different types of paint and relative prices for each. They can mix custom Corvette colors in any paint system based on paint chips in their library.

http://www.tcpglobal.com/kustomshop/ksprime.aspx

Whatever system you choose, I can't emphasize enough the importance of degreasing and dewaxing before painting or stripping. Wash the car throughly first. Then wash it again and scuff the entire surface with Scotchbrite pads and dilute citrus cleaner. Then wipe the entire car down with water-based wax remover. Be sure to use a tack cloth before spraying.

Lastly, here is a tip on how to confirm the type of paint presently on your car: Get some lacquer thinner at Home Depot, saturate a cloth with it and wipe it on an inconspicuous area. If after some rubbing nothing comes off then it's BC/CC. If some color comes off then it's lacquer. If it curdles, then it's enamel based. You could also sand a smalll spot. If it comes up with white dust then it's BC/CC, but if color comes up it's either lacquer or enamel.

Good luck!

I am going to paint my '65 Coupe. Some of the paint on the car I believe is original. All of it seems to be acrylic lacquer. I am probably going to paint the car with a base coat/clear coat paint, seeing to it that I try to get the correct appearance as best as possible in areas such as door jambs, hood surround, etc. using a flattening agent.

My question is as regards the proper primer to use over this original paint. I am not going to strip the car. That in mind should a urethane primer cause any problems after being sprayed over this lacquer paint? How about problems with a product such as Slick Sand (a sprayable polyester)? Thanks for any thoughts on this. Color is Goldenrod Yellow. Mike

[Mike M.]

Re: Correct Primer Over Lacquer

Mike: I appreciate all that advice. I have decided to use acrylic lacquer. I do a bit of car restoration (3 or 4 cars a year) and have mainly done bc/cc and some single stage stuff. My C2 friend has used AL and confirmed that it is very forgiving. I had done the 'lacquer test' which showed that what is on the car is lacquer. I plan to strip with some sort of fiberglass striper chemical (my jobber has that and I know that Ecklers has a product that my C2 friend has used.) I am trying to move up from a 2nd Flight status and using the AC would fit the bill there. I had seen that TCP Global link on this site doing a search but appreciate your confirmation on them. All your other points are noted and thanks much.
Mike

[Mike M.]

Re: Correct Primer Over Lacquer

One more question: if I am going to paint the car with acrylic lacquer and it is going over old lacquer (the old stuff comes off with a rag wet with lacquer thinner so I feel it is lacquer) is there still the need to strip the car? Any primer would be a lacquer based primer also. Thanks for the advice.
Mike

[Timothy B.]

Re: Correct Primer Over Lacquer

Mike,

The paint stripper will be faster and get in all the areas a rag will have a hard time reaching. It's your choice but those lacquer thinner fumes on a rag are probably not good the breath rubbing with a rag all day long.


Go get some paint stripper and try a spot to compare the time. If it's the old lacquer it will probably run off the car then you can squeege the stripper material to another spot re-using it. While it's soaking, wipe the old spot with lacquer thinner then move on like that. Just do a small one spot at a time and you will develop a system.

Don't drink to many beers and play radio to loud when working on the car or your wife will think you are having to much fun and find other house work for you.

[Bruce B.]

Re: Correct Primer Over Lacquer

Mike,
Have you considered stripping using 80 grit paper on a orbital sander.
I have done Corvettes this way a number of times and it is quick and easy.
No smell but lots of dust.
You can strip to the fiberglass and no need to gelcoat.
This method avoids having residual chemicals on the body surface.

[Mike B.]

Re: Correct Primer Over Lacquer

So long as the underlying paint is sound and is propperly prepped by scuffing and degreasing, then you should be able to go right over it with acrylic lacquer primer. The solvents in the primer cut into the old paint somewhat, but that's what gives it such good adhesion. It does not melt the paint off because the solvent evaporates very quickly leaving only the pigment behind. When you spray AL, it dries quickly but each successive coat "melts" into the next.

Be careful using strippers because they can leave solvent behind (although lacquer tends to breath better than modern catalyzed clear coats). Mechanical sanding can also do damage to the original features and can leave flat spots where there used to be curves which subtle as they may seem at first will show up when polished to a shine.

Lay on a few coats of high-build primer then gently block sand using 600-1000 paper before you start to top coat. Put down 4-6 top coats of color. If you want to get crazy, knock that down with 1000 before laying on another few coats of color using slower evaporating thinner in the final coats. The solvent dries very quickly and virtually as soon as you are done going around the car you will be ready to start again.

When you are done spraying try sanding the finish down with Abralon foam-backed ultra fine pads in 1000 - 4000 grit prior to polishing.

Lastly use proper respiratory protection and ventilation. The main solvent in lacquer thinner is acetone. I don't know the flash point but it probably is pretty low.

[Mike M.]

Re: Correct Primer Over Lacquer

I am stripping the car using Klean Strip stripper for fiberglass. Stripping the paint itself (Goldwood yellow lacquer) requires a good effort but it will come off (using a plastic spreader to get it off). The reddish primer seems to be way more difficult. My question: does this original primer have to come off too? (Lord, I hope not!)
Tks,
Mike

[Mike B.]

Re: Correct Primer Over Lacquer

Purists will say to take it off, but if it is sound and intact it is probably OK to leave it. If the primer doesn't dissolve it may not be the original paint - it might have been an epoxy primer or resin based gel coat layer. At whatever layer you stop, make sure there is no stripper left behind or it will cause future problems with top coats. Wash, sand, wipe, repeat, then put it in the sun for a while to evaporate off any residual solvents or the dreded pinholes could result.

[Norris W.]

Re: Correct Primer Over Lacquer

I think it is asking for trouble to paint over 47 year old original paint. I also think you should get the original primer off, and it's really not all that bad a process. All the way to bare glass also is an excellent time to look closely at the body seams and see any previous repairs. Primer won't "disolve" with any stripper I have ever used, but it will become softer and easier to remove after stripper, and that in itself makes it an unsuitable base for new paint in my opinion.

Over the years I'ver probably stripped 15 or 20 Corvettes and have tried various methods. The guy around here who I considered a Corvette expert in the '70's when I did the first one was insistent that the Dupont stripper was the only thing that was safe to use without side effects on the car, either sooner or later. His recommended proceedure was the Dupont stripper, removed with rubber bondo spreader, then the primer washed off with rags and laquer thinner while it was still somewhat soft from the stripper. For the first several cars I followed his advice to the letter, but the rag/laquer thinner step was slow and monotonous. Later I began using steel wool for the laquer thinner step, and although it was faster this person always said that I would leave very small particles embedded that would cause paint issues later. I continued to use it that way anyway for a long time, and both my Top Flight Riverside Gold '69's from the late 80's/early 90's were stripped that way and have had no residual steel wool issues. Later I began to use scotch brite pads in the place of the steel wool and believe it to be a much better option for several reasons. I've done 3 in the last couple of years (with a helper doing most of it under close supervision because I am now much lazier and less patient) and use close to the same method, although the materials have changed. For stripper I like the liquid Captain Lee's product that most of the Corvette parts vendors sell, and think it is not only much easier to use, but seems to give the primer a better head start for the laquer thinner/scotch brite pad. Basically we do about half of a panel at the time with the stripper and get it clean to the primer, and then wash the primer to bare glass with the laquer thinner while it is still softened. I try very hard to avoid getting stripper on the bare glass in doing subsequent areas. With the stronger strippers in the past I have seen some raising of the glass in areas where the stripper hits, but not with the Captain Lee's. When I've seen it demo'd at shows it seems they wash all the way to the glass with the stripper, but they are using carefully selected cut off panels with one layer of old laquer and don't have to live with it later. Another tip: whatever area you put stripper on, get it all off. Softened or wrinkled paint that is not removed, like needing a second coat for the stubborn stuff, so leaving it to come back later, causes more work. Paint that is softened with the stripper and allowed to dry hard is for some reason much harder to remove the second time, and again it's also the easiest time to get the old primer washed off. When we were stripping my '59 several months back I walked out in the building and my guy was rubbing on the original paint on the hood with the scotch brite pad and laquer thinner. He had run out of stripper. It was surprising how well just the thinner and pad were doing, but again it was 50+ year old laquer. That is probably the gentlest way to strip old laquer, but also would take considerably more time.

I think it is a big mistake to ever let a DA (random orbit sander) with paper on it touch fiberglass that does not need repair and additional attention before paint. In the past I've seen people on other various posts as referring to "down to the original gel coat". No Corvette has ever left the factory with gel coat. I've always thought that if you can't ski behind it or fish out of it, gel coat has no business on it. When somebody thinks they are sanding into the gel, they are sanding into the fiberglass. I have in fact used a DA on some of my cars that have been painted with BC/CC or even other products with hardener including one with Imron. The only sander work then has been to use a coarse disc, like 36 grit to cut into the paint and give the stripper a head start, being very careful not to cut through primer and touch the glass.

One thing we do have now is better primers. Modern products with catalysts offer some real advantages over the old laquer primer which never stops shrinking.

[Dick W.]

Re: Correct Primer Over Lacquer

So long as the underlying paint is sound and is propperly prepped by scuffing and degreasing, then you should be able to go right over it with acrylic lacquer primer. The solvents in the primer cut into the old paint somewhat, but that's what gives it such good adhesion. It does not melt the paint off because the solvent evaporates very quickly leaving only the pigment behind. When you spray AL, it dries quickly but each successive coat "melts" into the next.

Be careful using strippers because they can leave solvent behind (although lacquer tends to breath better than modern catalyzed clear coats). Mechanical sanding can also do damage to the original features and can leave flat spots where there used to be curves which subtle as they may seem at first will show up when polished to a shine.

Lay on a few coats of high-build primer then gently block sand using 600-1000 paper before you start to top coat. Put down 4-6 top coats of color. If you want to get crazy, knock that down with 1000 before laying on another few coats of color using slower evaporating thinner in the final coats. The solvent dries very quickly and virtually as soon as you are done going around the car you will be ready to start again.

When you are done spraying try sanding the finish down with Abralon foam-backed ultra fine pads in 1000 - 4000 grit prior to polishing.

Lastly use proper respiratory protection and ventilation. The main solvent in lacquer thinner is acetone. I don't know the flash point but it probably is pretty low.

Apparently you have never had the underlying paint "go to hell" after you applied another paint job over it. The resulting mess is not worth taking a chance. None of the lacquer products today are the same quality of the pre 1990's materials.

Lacquer based primer/primer surfacer is obsolete technology. Modern primer/primer surfacer is light years ahead.

[Paul D.]

Re: Correct Primer Over Lacquer

I used Capt Lee's and laquer thinner to strip my '67. A big mess,but worth it. I did a small section each day. I washed the WHOLE car after each day with Dawn. Even did the jams. The factory primer will come off with Brown scotchbrite and laquer thinner. Just make sure you wash ALL chemicals from the body every day. Took me better than a week and 1/2 to do the job. Anything with Red in the color is very expensive to buy. Walked out of the local paint store about $1300 lighter for the Dupont Chroma Base system(2007). Did not want to paint the car twice. Anyway took the BC/CC hit at judging,but been happy with the results of the BC/CC. Enjoy your project.....P..

[Mike M.]

Re: Correct Primer Over Lacquer

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I am about through stripping this '65. The car is real straight except for some minor previous damage on the rear and on right front. We are blocking the existing red primer and the plan is to spray some epoxy primer and then perhaps Slick Sand (sprayable bondo). Not sure if a final coat of lacquer primer is needed before the top coat of AL. Some photos are shown above.

[Jim M.]

Re: Correct Primer Over Lacquer

I used Capt Lee's on my 69 and when I was finished it pretty much looked like Mikes 65, down to fiberglass in some areas and some areas with some of the reddish primer left on the car. I had three coats of paint to take off and it took me the better part of a month to get it all off although I didn't work on it every day. I too washed the areas that I worked on each day and pulled the car out into the sunshine each day that I worked on it, so the car got a lot of sun time and the fiberglass was heated up pretty good on those days. I sort of felt that if I missed getting every bit of the stripper washed off at least the sun bake it out. I would sure stay away from sanding the paint off, too easy to dig into the fiberglass. It's been four years since I repainted my car and I have had no problems with the method I used. Not a fun job but if you take your time and do a little at a time over a few weeks or a month, it's not all that bad. Best of luck.

[Norris W.]

Re: Correct Primer Over Lacquer

Mike, I think you are making some decisions that you may regret later. As much work as it is to get it down to original primer it's a shame to leave a potential problem on the car. If you get it all off you know you have a solid base to start from. With 47 year old primer that is technology that you would not use today it could haunt you regardless of what you put on top. There're too many excellent primer products on the market now to take the chance of somthing showing an edge or crows footing later when you are this close to doing it right. I'm not familiar with Slick Sand, but am very familiar with Featherfill, which from your description I assume is a similar product. I wouldn't put a Featherfill type product on my lawnmower, let alone a fiberglass Corvette. I've seen too many issues with it on both steel cars and Corvettes. A bodyshop who does most of my work slipped it on some parts of a '65 GTO and '67 442 after explicit instructions not to use it, and I've had trouble with both. It's virtually impossible to feather out if you need to make a repair and hitting it with stripper, even aircraft stripper turns it to a chewing gum type gluey mess that is almost impossible to get off. The 442 had the hood shut with something laying on the core support and the small inside out ding turned into a spiderweb several inches in diameter and the trunk lid has crows feet you can see in the right glare.

[Dick W.]

Re: Correct Primer Over Lacquer

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I am about through stripping this '65. The car is real straight except for some minor previous damage on the rear and on right front. We are blocking the existing red primer and the plan is to spray some epoxy primer and then perhaps Slick Sand (sprayable bondo). Not sure if a final coat of lacquer primer is needed before the topped coat of AL. Some photos are shown above.

You are making a mistake if you do not use a system from one paint manufacturer such aslast DuPont, PPG, etc