Wrinkled lacquer over glaze

      The products and processes that could be causing this problem. August 29, 2001

Question
I recently did a cabinet job in hard maple and had a problem with the CAB lacquer topcoat wrinkling. I have a cabinet shop but sub out nearly all of my finishing and my experience is very limited.

The finisher used the following schedule: oil base stain, nc sealer, sand, oil base glaze, cab lacquer topcoat. The finish on some of the doors wrinkled slightly. We took those doors and sanded the topcoat smooth and shot another coat of CAB with no wrinkles.

I just sold another hard maple job and the customer wants the same finish, so I made a sample board with several colors of stain that I had in the shop, mostly oil base but a couple of lacquer base. The stain dried overnight, then I sealed this with thinned CAB lacquer to avoid two different setups, sanded, glazed with oil base glaze from SW, let dry for twenty-four hours or so and did a couple of topcoats of CAB. The same wrinkling occurred.

I talked to the guy at SW and he suggested using a latex glaze, which I am in the middle of making a sample with now.

Should I use a vinyl sealer under and over the glaze, then topcoat? Is latex glaze compatible with lacquer?

Forum Responses
From contributor R:
I had a similar problem with CAB lacquer. The SW rep said that the lacquer thinner we were using was an inferior grade (they sold it to us in the first place). I have a theory that a lot of manufacturers are using an alkyd resin blend for their lacquer, as lacquer never used to wrinkle. I base this on a conversation I had with a chemist from SW. I no longer use SW lacquers, as we often have to use glazes and I need a finish I can depend on.



From contributor D:
It sounds to me like the finisher just missed the window for shooting over the glaze. Oil based glazes I have used are touchy about this.

What works for me is shooting 2 light mist coats of vinyl sealer over the glaze after it has had at least 45 minutes to dry and not more than 3 hours. Then if schedule allows, I let that sit overnight before proceeding. I have no idea if this makes any difference, but whenever I have done that, I don't have lifting or blushing problems. I have had problems with glaze blushing and lifting (wrinkling) when I pushed the topcoats on the same day, even when I followed all the rules.

I also try to avoid leaving any glaze on heavy, if at all possible. I'd rather glaze twice if I had to, rather than have to do one heavy coat of it.



I think the above may be right about the wrinkling problem. However, contributor R has a legitimate point also. My own first impression was that the glaze was too heavy. Was that a Sherwin Williams glaze? I switched to a Lilly glaze and absolutely will not use any other kind. Since Valspar bought out Lilly, I'm not sure if they will have the same formula or same glaze. I understand that they will have a new type that will be compatible under CV and other catalyzed products.


The point about using a couple of light coats of vinyl sealer over the glaze is key. Obviously the cause of the wrinkling is the strong solvents in the lacquer thinner resolvating the glaze. A couple of light coats of vinyl sealer should isolate the glaze from attack by subsequent heavier lacquer coats. Try this technique first prior to changing anything drastically.


From contributor R:
Funny thing with the CAB lacquer, though. After the job had cured for awhile, we also had problems with aerosol touch-up lacquer wrinkling the finish. This was on projects that were not even glazed. Hence SW attempt to explain the problem as lacquer thinner. (we tried their best thinner, same results). I've sprayed lacquer for a long time and wrinkling was something you just didn't get unless you were using a glaze like Mohawk's heavy-bodied glaze or a film-forming glaze. Mostly, I use HULS utc or Gilsonite in mineral spirits or VM&P naptha, so there is no "window" other than letting the solvent dry. That's why I think there is some new secret ingredient in the resin. I know for a fact that they use a small amount of alkyd resin in their pigmented lacquers. I believe this resin cures and doesn't re-wet with solvent like lacquer is supposed to do. Re-wetting is what makes such fun things as glazing possible in the first place, else you rely on sanding for a mechanical bond and a glaze interferes with the adhesion.


From contributor D:
A couple things going back to the original questions. It was asked if a vinyl sealer should be used under and over the glaze. I know SW's CAB lac specifies their vinyl sealer MUST be used under that product. It is also not compatible with nc lac, nor are you supposed to use the CAB as its own sealer.

I can verify the incompatibility with nc lac. Not knowing about the compatibility issue with nc lac, I gave SW's CAB acrylic lacquer a try in my system. I like to use aerosol nc toners for light shading work and quickly found I had a problem. Unless I sprayed them very dry, they wrinkled up on the CAB. Successive coats of CAB over these toners looked weird/coarse. I called my SW rep and he had no idea why this was happening. Call to the SW chemist confirmed no can use nc lac with this product.

I don't know anything about latex glazes. I don't know much about using HULS for glaze since I just recently gave this a try. I had problems working with it because it dried so fast.



From contributor R:
It all depends on what you are doing. If you are doing a brushed glaze where you go back and brush out and blend areas in, mineral spirit glaze won't work as well unless you add a little linseed oil and I usually don't like to go there. Most of the glazing I do is an all-over wipe on, wipe off glaze to bring out the grain structure or distressing marks. For the darkened edges, etc., I prefer to use a shading gun over the even glaze. I also like my glaze to dry fast, as my boss always wants everything today!

As for the naptha, that really dries fast and I use it or lacquer thinner to do marbleizing or other techniques. You can take 3 colors of utc each mixed with naptha, say white, yellow oxide and burnt umber. Wipe on an even coat of the burnt umber over a coat of lacquer undercoat and then sprinkle on the other 2 colors and watch what happens. You can also blow the color around with an air nozzle or just let drops sit and dry. The possibilities are endless.

I also like to use water based pre-mixed tempera paint as a glaze. Water stain, 1 coat vinyl sealer, hand sand 320, wipe on some black tempera paint and wipe back off like stain (thin 50-50 with water). Let dry and scuff off tempera with a scotch brite pad everywhere you don't want it. This is a wonderful distressed or antique finish technique.

If you need that extra brushing time I usually use a commercial glazing stain like Mohawk's heavy-bodied glazing stain or Pratt and Lambert or McKloskey's, etc.



From the original questioner:
Someone asked if the glaze used was SW. I actually had SW glaze, but my finisher didn't want to use it because it was so thick, almost like mashed potatoes. You actually had to rake it out of the can. I don't know if this is typical of oil glazes or not. He had some oil glaze in nearly the same color that he used instead. It was called Old Masters I believe, don't know who makes it though.

The glaze I used for my samples was the SW oil glaze I had originally. Though I did thin it considerably with mineral spirits, I had the same wrinkling that he had with the Old Masters. I do know that he shot CAB over his glaze shortly after applying it, whereas I waited overnight.

The effect we're after is a slight softening or muting of the grain and we want to leave a little of the glaze color in the corners and along the profiled edges of the five piece raised panel doors. I don't know what the best and most foolproof way of getting there is.

I think I'll try the two thin coats of vinyl sealer, to isolate the glaze from the CAB topcoats.

Does vinyl sealer melt into the previous coat like lacquer or is it strictly a mechanical bond? If you can shoot lacquer sealer and topcoats over oil stain, why would the oil glaze cause problems--is it just a really thick stain or a different animal altogether?



Right, there is no sweating in time for the ML Campbell catalyzed materials. But other companies do have sweat times for some of their products: Akzo Nobel and Star, to name a couple.

You have to read and follow the spec sheets for each material you are using. That way you don't have to guess as much. The next line of research is a phone call to the tech support people of the materials that you are using.

In the case of Sherwin Williams, the tech support did not really help in my (uninformed) opinion. I am not a chemist. Those guys are supposed to have some background.

But what was recently related to those of use on the Professional Refinishers Email Group by a really good Mohawk/Star rep is that you do NOT use a CAB coating to lock in a glaze coat. You use (if you are using a CAB topcoat) a clear non-stearated vinyl sealer, preferably. And when in doubt, do as advised above and mist on the first couple of coats (my former Mohawk rep advises the very same technique because this seems to be a "safe" method in progressing your finish schedule toward eventual topcoating).

My first hunch is that a wrinkled lacquer over a glaze coat also has greatly to do with not respecting the re-coat window of the glaze coat. Manufacturer's glazes have their own working properties, including those open windows of time when you can "shoot the glaze" (otherwise you have to wait the full cure cycle for the glaze). The old Star glazes were, for example, made to be shot within two to six hours after their application or wait a full day of drying.

Vinyl sealer melts into the previous undercoat. But you have to watch out. Some manufacturers want you to scuff that vinyl sealer before you re-coat. Some manufacturers don't require that.

The glazing vehicle is not the same as the vehicle of liquid that your wiping stains sit in.



Since you are looking for a slight muting of the grain, have you tried experimenting with shading toner, which is made with opaque pigment, as opposed to standard toner, which is (or should be) made with translucent dyes? Make a toner with your topcoat and 844 tints adjusted to whatever strength suits you. You can also blow this in corners using a touchup gun and just enough air pressure to get the product out of the gun. It may not give you the look you want, but if it does, you can save a lot of time and work, and at the same time solve your lifting troubles.


I know the answer to this problem! We learned that CAB lacquers are not compatible with oil base finishes. The oil in the finish will corrupt the lacquer and make it wrinkle up. Try another topcoat.

The other problem we encountered with CAB lacquer is its pot life. I sprayed 97 doors and drawer fronts for a job I did, then came back the next day to spray them again and when I did, the new lacquer went on smooth but soon looked like someone had sprayed stripper on the doors--the finish wrinkled horribly. The problem was that the product was almost a year old and had simply gone bad. The company that sold them to us paid me to make and finish 97 doors and drawer fronts again.



The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor B:
Wrinkling in the topcoat usually occurs when the layer of finish below is not fully cured or the sealer has not adequately sealed off what lays below - glazes, stains, etc. These materials also must be compatible with the topcoat. Some finishes, especially when mixing brands, often cause these kinds of problems. Wrinkles in the topcoat also may be due to not enough dry time and/or coating with a sealer that does not prepare a solid barrier for the topcoat to lay down smoothly. Successive coats of CAB acrylic and catalyzed lacquer can cause problems because you must allow ample time for the layer beneath to cure enough to prevent migration into previous coats. You have two ways around this: either decrease time between coats (apply coats a few minutes apart) or wait until the previous coat has cured enough to spray successive coats. CAB and especially catalyzed lacquer cure time is greatly shortened when heat is applied.



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