Paragraph 57. The shellac finish is one of the hardest of all to produce. This is a finish which is known as the French polish. This should be undertaken only on small pieces of work where a very fine polish is desired and where there is ample time to give to the task. A fine French polish cannot be obtained in a few minutes. The foundation coat must be applied as already explained, then a good coat of shellac should be brushed on with a soft brush.

Shellac is a sort of resinous substance which is gathered from the bark of certain trees of India. This substance is dissolved in alcohol and then applied very much like varnish. The best grade of shellac is mixed with pure grain alcohol; this makes it rather expensive, so wood alcohol, which will do very satisfactorily for ordinary work, is usually substituted. Denatured alcohol is very frequently used, but it sometimes happens that denatured alcohol fails to dissolve the shellac because the substance used in the denaturing process will not dissolve shellac, and for that reason when it is added the shellac settles in the bottom in a sort of ropy substance and it is impossible to get satisfactory results with it. It is best to use wood alcohol unless you can buy a quality of denatured alcohol prepared on purpose for shellac work.

After the first coat of shellac is added it should be allowed at least twenty-four hours in which to dry and harden. By carefully examining the surface you will then find that it is somewhat rough. It should be made perfectly smooth before another coating of shellac is added. A few drops of linseed oil should be placed on a piece of sandpaper and then the shellaced surface should be carefully rubbed in the direction of the grain. The purpose of the oil is to prevent the rubbing from causing the shellac to become sticky. The linseed oil also helps somewhat in building up a polish. When the surface has been rubbed perfectly smooth, it is then time to begin the more difficult portion of building up the French polish.

A French polish is rubbed on with a rag. A "rubber" is made by twisting a piece of soft cloth into a wad and then covering it over with a small piece of cheesecloth about five or six inches square. The inside portion of this wad is saturated with the shellac, then by twisting it in the square of cheesecloth the shellac will be allowed to ooze through onto the surface of the work. The "rubber" is occasionally dipped into linseed oil and then rubbed over the surface of the wood in a circular motion. As the rubber is gripped the shellac oozes through and mixes with the linseed oil and a beautiful polish is built up. The rubber must be kept in constant motion while it is on the surface; if it is allowed to stand still it will stick and mar the polish very badly. The skill in this work is shown by being able to rub the surface to a perfect finish without leaving any uneven or marred spots. The rubber is opened from time to time and the inside portion is dipped into the shellac. Care must be exercised not to have too much shellac on the rubber or the work cannot be satisfactorily done. It will require several hours to rub even a small surface no more than a foot square to a beautiful rich polish.

A very excellent shellac finish is very often produced by applying the shellac with a brush and rubbing it down in the same fashion as a rub varnish. If you desire to do this instead of rubbing on with rag rubber, as explained, apply the second coat with a brush, allow it to dry about twenty-four hours and rub it down with sandpaper and oil in exactly the same way that the first coat was rubbed. Apply a third or even fourth or fifth coat, carefully rubbing down each coat before the next is added. In this way a complete smooth layer of shellac will be built on the surface of the board. For a final rubbing it is well to use ground pumice on a rag moistened with linseed oil. This is very much finer than sandpaper and will produce a more beautiful polish. By "spiriting off" with a piece of cheesecloth which has been very slightly moistened in alcohol, the surface may be rubbed to a magnificent gloss. This requires some skill, because if the rag with which the final rubbing or spiriting off, as it is sometimes called, is done is a little too moist with alcohol the entire surface will be destroyed. This final polishing rag must be so nearly dry that it will seem only the least bit moist when touched to the back of the hand. It will require a great deal of experimenting and patience to produce a satisfactory finish with shellac. It is well worth your while to attempt it; do not be satisfied until you get good results.