How to Work With Shellac

TIPS AND TRICKS

People use shellac on their woodworking projects because of the results it produces. Shellac truly brings out the beauty of the wood and can be applied by different techniques: the beginner can quickly become comfortable with padding techniques, while professionals can create a remarkable finish using French Polishing.

Here is some information you may find helpful.

SHELLAC FLAKES

STORAGE

Store your shellac flakes in a cool, dry place, and they will remain fresh for years. Humidity and light are the two factors that affect the quality of shellac flakes. If the flakes should clump or cake together, this is called blocking. This can happen in warm weather, but it does not indicate there is anything wrong with the flakes. Just break up the blocks and add to the alcohol.

THE CUT

With regards to shellac, the term “cut” refers to the proportion of shellac (in pounds) to alcohol (in gallons). Thus, a 2-pound cut means 2 pounds of shellac flakes dissolved in a gallon of alcohol. Since few people would use a gallon of shellac for a project and because liquid shellac has a relatively short shelf life (approximately 6 months), it is best to mix only what you think you will need. For example, to make a 2-pound cut, you could mix ¼ pound of flakes with 1 pint of alcohol.

Below is a chart for mixing 8 - 10 ozs. of finish at various cuts:

#1 cut...........................1 oz flakes.....................8 oz alcohol

#2 cut...........................2 oz flakes.....................8 oz alcohol

#3 cut...........................3 oz flakes.....................8 oz alcohol

Of course, you can make a little over a pint of finish by doubling the flakes and the alcohol.

TIMING

The flakes can take up to 24 hours to completely dissolve. It helps to stir the solution now and then.

STRAINING

After the flakes have totally dissolved, the liquid will need to be strained either with a fine mesh paint strainer or tightly woven cloth.

BUTTONLAC

When dissolving the buttonlac, it is best to crush the buttons, as they will dissolve much quicker. I wrap the buttons in a clean cloth and smack them with a hammer. Perhaps you have a more creative method.

There are three ways to remove the wax from buttonlac:

1. Wrap the pulverized buttons in a double layer of large paper coffee filters. Tie the top closed and set this in the appropriate amount of alcohol.

2. Dissolve the pulverized buttons in the alcohol, then filter it through a couple of large coffee filters. This method takes time as the solution filters through slowly. There is also some alcohol evaporation.

3. Dissolve the pulverized buttons in the alcohol and allow the solution to sit for several weeks, then decant the dewaxed layer into another container. This method is the least recommended.

STORAGE CONTAINERS

Do not store shellac – either liquid or flakes - in a metal container.

AGING SHELLAC MIXTURE

If your mixed shellac is over six months old, it is best to test it by pouring a drop onto a hard, non-porous surface, such as glass or clean metal. If it does not dry to a hard surface in an hour or so, discard that batch and mix up a new one.

WHAT KIND OF ALCOHOL TO USE

Some folks talk about using chemical-grade ethanol to mix with their shellac flakes. I myself have never run into any problem using the denatured alcohol from the paint or hardware store. You will know if there is a problem if you get “blushing” when the coat has dried. Blushing will indicate that either your alcohol has water in it or that you are applying the shellac on a very humid day.

APPLICATION

As with any stain or finish, it is wise to try it out on a scrap piece of the wood you are planning to finish.

In air temperatures above 70°F, the alcohol in shellac dries more quickly. Therefore, it is essential to apply the shellac quickly and avoid revisiting areas you have already covered to fix missing spots. Because one coat of shellac burns into the next, any missed spots can be covered on the next coat and still produce a level finish.

If you are using shellac for the first time, or for the first time on a new species of wood, it is wise to try it out on a piece of scrap, along with any stain you plan to use, to see what you can expect of the finished product.

WIPE-ON/PADDED:

With padding, I use a 1 1/2 to 2-pound cut of shellac. Use a soft, lint-free cotton cloth formed into a pad. You can put the shellac into a container so that you can 'blot' the pad against the side after you have dipped it into the finish, or you can put your shellac into a squeeze bottle and apply it to the pad this way. In either case, you want enough shellac on the pad to moisten it, but not enough so that it drips.

I like to use as long a stroke along the surface as I can. I find I can usually cover an area and even pass over it a second time to even out the material, but then I leave it. Remember, if you don't like the way the finish is laying down, you can fix it on the next coat. One of the benefits of using shellac!

BRUSHING

With brushing, I use a 1 to 11/2 pound cut of shellac. It is best to use a natural bristle brush or a Taklon synthetic brush. The method is like padding in that you don't want too much material on your brush, and you want to move rather quickly. I set the brush on the wood a short distance from the edge, as there tends to be more material dropped at the initial contact. I move the brush in one direction, then back over the contact spot towards the other direction.

SPRAYING

Spraying shellac is similar to spraying nitrocellulose lacquer regarding application. They are also similar with respect to the problem of blushing. Lacquer retarder will prevent blushing with shellac.

FRENCH POLISHING

I will not try to describe French Polishing here, but will suggest checking out books and articles by Jeff Jewett and Bob Flexner for detailed information on French Polishing and more on the above methods. You can also view this video: ADD LINK TO FRENCH POLISHING VIDEO.

SHELLAC AND WATERBORNE FINISHES

Shellac works great as a barrier coat between oil stains and waterborne top coats. There is often a situation where oil-based stains are used in conjunction with a waterborne topcoat. This can create a problem of adhesion. At the very least, the stain will need to cure for 4 or 5 days for the finish to bond correctly. If, however, you were to apply the stain, allow it to dry overnight, then apply a coat of dewaxed shellac, you could move ahead with the waterborne topcoat within several hours.

Waterborne finishes tend to have a 'cool' look, even over a stain. A coat of dewaxed shellac before the waterborne topcoat will help 'warm up' the end result.