Any harm in thinning Deft laquer?

[ryan.s]

I have a can of brush on Deft laquer in high gloss and am thinking of thinning it with some naphtha to minimize brush marks. I was thinking of a 50/50 ratio. Will I have any problems if I do this? The reason I ask is it specifically says on the can that it must not be thinned or sprayed but I always hear of people thinning laquer and was wondering if it warning was specific to this brand only. Thanks.

[jabe]

I've sprayed Deft lacquer for many years (25 + yrs) and have never thinned it. I have not tried brushing it but deft is very forgiving, try brushing it without thinning on a scrap board first. Contrary to what they say, it does turn yellow. They tell you not to spray it cause of liability. It sprays very well, it's not affected by humidity so you get no clouding in the finish even when it's raining outside.

I now use Deft water-base lacquer, and it needs to be thinned before spraying. I use 7 oz. water to 1 qt. Deft water base lacquer b4 spraying with my Fujii HVLP sprayer, the result is really nice & clear. The water based lacquer seems to cure faster and the finish seems harder. Water base lacquer cost little more but but you get more by thinning it. Clean up is just with water so you save there too, also it's better for the environment.

[cabinetman]

If your lacquer is not waterbased and it is a brush grade, it has a retarder in it to keep it from drying too fast. You can thin it for spraying by using lacquer thinner, if it is lacquer based. Do not use MS or Naptha. The pre-catalyzed lacquer I use I thin 50% with lacquer thinner for spraying. The consistency you use may be of a lesser percentage. If you think it's too thin, it won't be ruined, you just won't get the build.

For lacquer thinner based lacquer, you can add retarder to slow down the dry time or to deal with humidity. If you are thinning brush grade to start with, there is already some retarder in it. If you don't want the gloss look, you can add a "flattening agent" to give it a satin finish. You could get that at an industrial supply, like Sherwin-Williams. SW may carry it in their retail stores. I get it from their industrial outlet. Or, auto paint supply stores should have it.

Some manufacturers call their products whatever they want. I've heard of water based lacquer, water based varnish and other wild terminology. You have to read the labels and determine what the base (vehicle) really is, and whatever recommendations they give. But basically, the main bases are alcohol (shellac), mineral spirits/paint thinner (oil base, and oils), lacquer thinner (lacquer), water (water based). If the label isn't clear on what the base really is, check for the method for clean-up, and it will say what to use.
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[Jeffrey Schronce]

I now use Deft water-base lacquer, and it needs to be thinned before spraying. I use 7 oz. water to 1 qt. Deft water base lacquer b4 spraying with my Fujii HVLP sprayer, the result is really nice & clear. The water based lacquer seems to cure faster and the finish seems harder. Water base lacquer cost little more but but you get more by thinning it. Clean up is just with water so you save there too, also it's better for the environment.

Wow. Really? 7 oz water to 1 qt of waterbourne finish? I would have thought that would have destroyed the crosslinking, etc.

Water based is more expensive, however there are more solids in the can versus oil based thus actually ends up being less expensive. How much volume of fluid you get for your $ is really not important, rather its the solids you are getting. Remember, solvent goes away.