Refinishing a Wax-Finished Table Top

Advice on removing and existing wax coating, sealing the piece with shellac, and applying a compatible lacquer topcoat. December 30, 2007

Question
My customer now wants a more protective coating on their pine kitchen table, which has a waxed finish. I am going to spray lacquer over an amber shellac base coat. I have stripped and degreased, sanded, and steel-wooled. I just want to make sure all the wax is removed so I don't get horrible fisheye.

Forum Responses
(Finishing Forum)
From contributor D:
I'm not sure if you mean the current finish is only wax or some type of finish that has wax on it. The latter should not be any special problem, so I am assuming you have the former. The wax is stubborn to come out entirely once it has been applied to bare wood.

Strengths of shellac are adhesion and barrier qualities needed in such situations. I would probably spray 2 coats 1.5# cut shellac and let dry overnight. Then proceed with your lacquer system. Make sure the shellac is dewaxed variety or adhesion issues between shellac and lacquer may result.

If you have an adhesion problem between shellac and wood, then you have not removed enough of the wax that was used as the previous finish. In which case, re-strip, wash thoroughly, and take another run at it. Your schedule sounds basically okay, but I don't see the need for any steel wool subsequent to sanding. In fact, could be a detriment.


From contributor T:
A shellac barrier coat is a good suggestion. I wouldn't expect fisheye unless the owner also used a polish like Pledge that contains silicone. If she did, a good shellac barrier coat will usually work and it doesn't need to be dewaxed unless you're going to use polyurethane over it. The only suggestion I would add is to keep your lacquer coats very thin. Thick lacquer coats will burn into and through a shellac barrier and (if there is silicone) your fisheye can suddenly reappear.

From contributor K:

I think it's a mistake to *not* use dewaxed shellac. Why take the risk no matter what finish goes over it?

From contributor T:
Certainly would be the safest approach. The rationale for my comment is based on the addage "shellac sticks to everything and everything sticks to shellac," which is almost true. The exception is polyurethane, which doesn't like to stick to anything including itself. It especially doesn't like stearated sealers and waxy shellac, so dewaxed is better if urethane is the required finish.

Wax is a natural plasticizer in shellac, and as such is usually desirable. The gentleman who introduced me to shellac would often add a few drops of cod liver oil ('twas a long time ago) to improve it even more, and the oil used in French polishing not only lubricates the rubber, it also increases the plasticity of the shellac.

As for lacquer over shellac, the solvents in lacquer will bite into the shellac and thus create an excellent bond, whether it's waxed or not. In fact, a thick coat of lacquer will burn clear through a shellac barrier coat, which may not be a good thing if there's silicone in the wood.


From contributor N:
If you are trying to remove a wax coating on raw wood, first you do a TSP rinse followed by clear water, then an oxalic acid rinse followed by clear water. These rinses are applied with atomizers, bug sprayers. The clear water rinses are done with power washers set at maybe 600 psi with the idea that the water should be bouncing off of the surfaces and not soaking or driving your materials into the surfaces.

Then you can follow through with a solvent rinse. This is done by hand with rags. You can use any solvent that will attack wax, such as mineral spirits (paint thinner), xylene, toluene, lacquer thinner, acetone, MEK, etc. Xylene and toluene are noxious and absorption into the skin is something you want to avoid. The others have varying degrees of breathing issues. So take precautions. Odorless paint thinner is the safest of the solvents.


From contributor S:
Mohawk sells a product called Waxwash that, when used according to the directions, I've had good results with.