Is it true that the old lacquer paint will crack if not waxed at least twice a year? Had a paint guy tell me thats why my paint is starting to get a lot of surface cracks. He said the wax keeps lacquer soft and prevents cracking. What's your opinion??

 

Heck old lacquer will crack even if it has been waxed twice a year. It might help in some way, but I think its going to happen no matter.

 

Even if its waxed 10 times a year! It is very brittle. It will crack at all the usual stress areas of the car.

 

lacquer shrinks there is no way of stopping it.

 

Been down that road before.

 

Paint films, including lacquers crack for several reasons.

Drying shrinkage. As the solvent leaves, the film shrinks and if applied to thick it will crack. How the film is dried is critical to the durability of the final product. High temperature drying causes the thermoplastic resin to flow and reduces drying stresses.. A lacquer should be applied in multiple coats with thorough drying between coats.

Plasticizer migration. Plasticizers are added to the paint to keep them flexible. Cheap ones will evaporate and migrate out of the film quickly. The smell of a new car is the plasticizer and residual solvents leaving.

Over extending the binder. If the paint has to much fillers in it the film will be weak and prone to cracking.

Substrate problems. The surface coated will have a dramatic effect on durability. Fiberglass needs to be well cured and carefully prepped prior to application of the top coat. Bondo, and the resins used to make the body contain styrene, a residual solvent which will migrate through and into the film. Bondo and body fillers will shrink and carry through to the top coat. Fiberglass will absorb all kinds of things that will migrate through to the topcoat and cause problems.

Substrate flexing. If the substrate flexes enough the film will stretch and eventually crack to relieve the tensile stress on the film. Thinner films are more flexible.

Waxing can improve the longevity of a coating. Some can contain effective plasticizers that will help keep the film flexible. They also can provide a protective barrier for abrasion and oxidation.

In summary automotive Acrylic lacquers used to paint Corvettes are extremely durability. They use the best resins and additives. They fail do to bad application and/or bad preparation. Witness forty year old paint that is still good. My 64 had areas on the back and sides that were still in excellent condition when I repainted it. There were no cracks do to paint failure only substrate failure and poor body prep from accident repairs.

JW Chemist

 

The car was painted 1986 or so, had cracks at stess points with in 2 years , but in the last 2-3 years I'm seeing little tiny cracks all over ,looks like some are down deep & some have surfaced.
Guess it's time to bite the bullet, strip & repaint

 

Thanks for the chemistry class. Actually I am pretty familiar with the chemistry and I agree with what you say. I have almost forty years of applying paint to Corvettes, and Its a fact that forty year old lacquer is mighty brittle and I don't care how much plasticizers you pour on it, that ain't going to change much. There are very few real original paint cars that are still presentable. Only if it has been very well protected, especially from the sun, will it last long.
My `58 for example was painted twice by `62. That don't say much for original lacquers ability to brave the elements. I agree that most times the problem is with the substrate, but in the real world, out of the chemistry lab, that's what we deal with. This fiberglass beast is difficult to tame.

 

there is only one fool proof way to keep lacquer paint from cracking......leave it in the can.....

 

After forty years, its probably cracked in the can.

 

without getting into the chemistry...good friend of mine may god rest his soul, back in 1980 bought a brand new Ferrari Boxer BB512 which at the time was the Enzo of the day. Made the mistake of pointing out the cracked laquer on the roof of this hand-built fine Italian car the kicker was I asked him cracked lacquer was on the option list...didn't talk to me for a week

 

Guys,
My car was painted with lacquer in 1985 and there are no cracks. It looks beautiful. That being said it will chip easier. However, it is also very easy to touch up.
As for waxing, I have been told the exact opposite. Body and paint guys have told me that when you wax lacquer you prevent it from breathing and that will ultimately make it crack. I did not wax my car for a long time and only used fill and glaze(Maguires #7) This past year I couldn't stand it any longer and finally put a good coat of wax on it. It made it look great. As for cracking, none yet but I will keep you posted.

 

Garaged, inside almost all of the time, sees little sun. Conditions the normal car dont enjoy.

How far did I miss it?

 

My brother- in -law has lacquer on his 61 vette,been there 35 years and is not cracked, and looks very nice. He does polish it a couple times a year. Bill58.

 

You are right on. Just like most of the cars on this forum.

 

I had a neighbor point out the cracking on mine, was repainted in 82
and there's so many cracks I told him it was an alligator paint option that costs more to get. He believed me !

till I told him the truth.

 

Gotta love the old 512!! I would've been pretty upset if it had started cracking so soon in one of those!!

 

I guess it does matter whether or not the paint is exposed to the elements. I haven't painted in years but I used to do custom paint on motorcycles with lacquer. I painted my brother's 1975 Harley Sportster in 1980 and it never cracked by the time he sold it a few years ago.

 

Painted my car about 1992 with Dupont primer and lacquer after gelcoating. It never sits outside more than a couple hours a month at most. Noticed about a year ago two small areas of some cracking developing - hard to spot on yellow. One area had some repair under it but the other area was factory virgin fiberglass so I'm writing it off to the paint and not substrate problems. I'm pretty much resigned that it will slowly spread over the years. Also a few tight stress cracks and some separation over bond joints in door jambs which are pretty much SOP with lacquer over jointed, multi-panel fiberglass.

 

Wayne:

you crack me up, my friend.

Mike