If you're finishing your furniture with shellac, consider using shellac flakes. Although shellac is also sold in liquid form, you can dissolve it yourself to ensure that the shellac will be fresh, which will pay dividends in the finished product.
Select the kind of shellac flakes you want to use. They're available with wax or without, as buttons or flakes, and in a variety of colors, including superblonde, blonde, orange, ruby and garnet. The lighter colors are the result of bleaching and have a shorter shelf life than the darker colors.
Determine what cut of shellac you want. In terms of shellac, "cut" is a measurement of how many pounds of shellac flakes are dissolved in 1 gallon of alcohol. A 2-lb. cut, for instance, has 2 lbs. of shellac flakes for every gallon of alcohol. In general, the lower the cut, the easier the shellac will be to apply to furniture. Lower cuts do, however, require more coats than higher cuts. If you've never used shellac before, start with a 1-lb. cut, or 1 lb. of flakes in 1 gallon of denatured alcohol.
Break up the shellac flakes before dissolving them to reduce the amount of time needed for dissolving. This can be done by putting them in heavy-duty bag and smashing them with a rolling pin or some other hard object. Some flakes like to put up a fight, so don't try to smash them with your hands, as you could get cut. Only spend about 3 minutes on this, since, ultimately, the denatured alcohol will dissolve all the flakes, no matter their size.
Pour the shellac flakes into a non-metal container that has a lid. Pour on the correct amount of denatured alcohol, then stir. The flakes won't dissolve right away, but over the next several hours they will try to form a lump at the bottom of the container. Stir periodically, covering the container between stirrings to prevent contamination. If your container has a tight-fitting lid, shaking is an excellent way to mix the shellac.
Strain the shellac mixture once the flakes are totally dissolved. This could take several days, so be patient. To strain, pour the mixture through a paint strainer or loosely woven cheesecloth into another jar. Then cap the jar and write the date on the container. Try to use the shellac within 6 months.
De-wax the shellac, if needed. If the shellac flakes you bought were not the de-waxed variety, after a while you'll notice a layer of wax on the bottom of your jar of mixed shellac. Most of this wax can be removed by repeated straining, but it's easier to pour or use a siphon to remove the shellac from the jar. If you pour, go slowly and carefully to avoid stirring up the wax. If you do stir it up, simply let it settle to the bottom and try again. De-waxing is your choice, but leaving it in there could make the shellac appear cloudy on your finished product, and it will definitely make the shellac less water-resistant as a finish.