Set 1

We have had many calls from luthiers who are learning to French polish as well as students of luthiery who have decided that French polish was going to be their choice of finish. We have done our best to advise them over the telephone and try to answer all of their questions. We will try to list as many questions and answers that we can recall. The following questions are the most common that are asked, either during the lesson or by telephone afterwards. This may help provide solutions for you if you should encounter any problems as you work.

Q: Where can I go to learn to French polishing? Are there any schools that teach the art of French polishing?
A: Up until a short time ago (1997), there was a school known as the American School of Luthiery which provided a class strictly for students that wanted to learn French polishing. The class was taught using a "hands-on" teaching technique by America's foremost french polishing expert Eugene Clark.. We would suggest that you contact Todd Taggart of Allied Luthiery.

Q: A friend of mine said that oil is not good for the guitar. Can you French polish without oil?
A: We would argue that, if properly done, very little oil is used for French polishing. We would also add that the oil is spirited off at frequent intervals during the French polishing process. Any residual oil is removed during the final polishing and cleaning of the completed instrument. We can't think of any reason, structurally or acoustically, why oil is bad for a guitar. Yes, it is possible to French polish without using oil. It is, however, very difficult to master the technique and takes a great deal of practice. If not properly done, the many layers of shellac will not be amalgamated and may invite problems such as crazing.

Q: Can you grain and pore fill with something else besides pumice? If so, why bother with the pumice?
A: Yes, we have and know luthiers that have tried and experimented with a number of different methods to grain fill with great success. Each luthier claiming that his method works very well. Again, we must stress that there are many methods to achieve the same goal. Here are 4 methods used by many great luthiers.
  1. Five-minute epoxy: The epoxy is mixed and then spread onto a small area of the guitar at a time. A razor blade or spreading tool that is perfectly straight with "safe " corners is used to spread the glue. Safe corners means that the sharp corners of the blade has bee removed to eliminate the possibility of scratching the surface of the guitar. Timing is important at this stage. The goal is to mix and spread just the right amount of glue with a minimum left to remove and to get the glue into the grain before the epoxy begins to harden. Correctly done, a very small amount ((about 1/4of a teaspoon) Will be enough to complete ½ of the back plate of the guitar. We let the first application of glue harden for about two hours and repeat the process. After the grain has been filled, we sand the entire guitar with 400 grit wet and dry sand paper until the excess glue has been removed.. We use olive oil as a lubricant for the sand paper. If no lubricant is use the sand paper will load and be useless almost immediately. We found that this is the best alternative to pumicing. As a matter of fact, we are now using this method of grain filling almost exclusively.
  2. Hide glue/wood fiber: Hide glue is spread onto the surfaces and then wet sanded. The paste generated from the sanding is rubbed into the grain. This method works well for some. The glue tends to thicken as it picks up the wood fibers and is difficult to spread into the grain. A good clean up is also time consuming. With practice, this is also a good alternative to pumicing but takes much longer.
  3. Ready-made grain fillers: Pre-mixed canned grain fillers must be tinted with paint toners to match the color of the guitar. Once mixed, it is spread and rubbed into the grain using a course cloth. With the scores of colors in a single species of wood, satisfactory matching of the colors is practically impossible and will show through the finish. The material is usually difficult to press into the grain and very seldom produces good results.
  4. Powder glue and wood toners: Powdered wood putty (glue) is mixed with paint toner to match the color of the guitar. It is then mixed with water into a paste. The paste is rubbed into the grain, let dry, and then any excess is removed by sanding. Again, a wood toner must be mixed with the powdered material to match the wood grain. Matching the color of the wood is difficult and even a minor bit of sanding can produce white specks.. We think that this is a very poor substitute for pumicing or epoxy.
    These are just a few methods that were designed to replace the pumicing procedure. In addition to the above methods, we have tried using some of the new polyurethane glues as grain fillers with very poor results.

Q: I have seen white specks and streaks in French polished guitars. I suspect that this is the pumice showing through the finish. Is this what happens with all French polished instruments where pumice is used for grain filling?
A: No, this certainly is not typical but does happen. You can minimize the possibility of pumice speck showing through the finish by "clearing" the pumice before application. Some white specks are mineral deposits usually found in hardwoods and can be mistaken for pumice specks.

Q: My French polishing goes pretty well until I get to the waist. The waist looks dull and lumpy. Can you tell me what is wrong?
A: Yes, you are most likely removing as much shellac from the waist as you're laying on, leaving the area uneven with little or no shellac. This is caused by the muneca being wet around the edges. If the muneca is too wet around it's edges, negotiating the sharp bend at the waist will cause the wet edge to strike the surface and "plow out" the shellac that was previously applied. Remember to "wring" the muneca often to be sure that no part is too wet. Wrap a paper towel around the muneca and squeeze. This will remove the excess shellac mixture from the muneca.

Q: My muneca leaves deep marks in the finish as I work. What am I doing wrong?
A: Three things may be wrong. First, be sure to use the "pull over" technique taught to us by Eugene Clark. Use circular strokes followed by straight line strokes and back again to circular strokes. Second, the covering on the muneca may be clogged up or has accumulated some foreign particles. Clean or replace the muneca cover. Third, the quality of the covering material on the muneca will create marks in the fresh finish. Try changing to very well-worn t-shirt material. This softer cloth covering should solve the problem.

Q: You use the term "amalgamated". What does this mean?
A: To amalgamate simply means to blend. The purpose of French polishing is to blend the hundreds of microscopic layers of shellac into one single, high quality, hard layer of shellac. In this way, the finish can be leveled without sanding through successive layers of finish, leaving unsightly "halos" that will show through the finish.

Q: Can shellac be sanded and rubbed out like lacquer? If so, why not spray it on instead of going to all the work of applying the shellac by hand?
A: Yes, shellac can be applied and rubbed out much in the same way as lacquer. The big difference is that lacquers are designed as emulsifying products. That is, each successive layer of material chemically amalgamates with the previous layer making it possible to spray, sand, and rub out the final finish without layer sand-throughs. This is not possible with shellac. If you were to spray shellac, the layers will be very thin and would not amalgamate. Any attempt to sand and rub out to a fine finish would cause layer burn-throughs. Again, the best way to amalgamate shellac is by the pressure of the muneca using oil as a lubricant.

Q: I was almost finished with French polishing the top of my guitar when I put a long 2 inch scratch in it with my fingernail. Should I try to fill it or just commit suicide?
A: Put away the gun. This is usually a simple fix unless the scratch went into the wood. Load your muneca in the same way you would to body the guitar. Use 5 or 6 drops of shellac with 3 or 4 drops of alcohol. Add a small drop of oil and a very small amount of pumice. Rub the area of the scratch until the scratch starts to get smaller. Let it harden for about an hour, reload your muneca, and repeat until the scratch is gone. Be very careful as to not overdo the pumice! Now sand the area with 1200 grit wet or dry sandpaper and reglaze the repaired area to a high polish.

Q: After seal coating the soundboard of my guitar, I noticed that it appeared "blotchy". There were light and dark areas all over the top. Can you tell me what caused it? What can I do about this problem?
A: It is possible that the grain in the darker areas were raised more than the grain in the light areas. Wood with raised grain will darken with finish on it. It is also possible that it might just be the nature of that particular piece of wood. At any rate you should scrub off the spit coats of shellac using just alcohol. This should be an easy job at this stage. The very thin layers will wipe right off with a course folded cloth. Terry cloth would be our choice. When all of the shellac is removed, wash the entire top with alcohol. Sand with 400 wet or dry sandpaper using olive oil as a lubricant. Let the oil dry off of the guitar for about 24 hours and resume spit coating as usual. This will solve the problem.

The following two questions have been asked many times and always get the same answer:

Q: I am a professional guitarist and a collector of guitars. Most all of my guitars are French polished. It seems that each guitar has accumulated dozens of scratches on the top and some are showing wear on the upper bouts. It would cost thousands of dollars have the guitars professionally refinished. Would you advise me to try to refinish the guitars myself? If so, how would you go about it?
A: Most anyone can French polish a guitar if they have the right materials and information. French polishing is made to order for instrument collectors, dealers and guitarists. We would advise anyone who is interested to give it a try. You have everything to gain and very little to invest. It takes no special equipment and can be mastered in a short period of time.

Q: I lent my hand made, French polished guitar to a real good friend and it was returned to me with over a dozen nail scratches in the top which will cost me hundreds of dollars to have fixed. Do you think that I can fix it myself? Would this be a case ofjustifiable homicide?
A: A jury might acquit you if all 12 of them are guitarists. Chances of that may be pretty slim. Lets solve both of the above problems as follows: Do not try to sand out scratches and marks in French polish. Many French polished guitars are finished with colored shellac and you run the risk of sanding through the very thin finish creating light blotchy areas. If this happens, you may have to strip off all of the old finish and start over. Lets repair the guitar finish as follows:
This time we are going to violate the "no-shellac rule". Remember that when we grain filled the guitar, we did not add shellac as we pumiced. This time, however, we are going to add pumice to the muneca as well as alcohol and oil. Assuming that only the top is damaged, here is how we are going to proceed.

Lets first add a few body sessions to the entire top of the guitar making sure that we have fresh shellac to work with. Load the muneca with 5 or 6 drops of shellac with a few drops of alcohol. Add a small drop of olive oil and glide onto the surface of the guitar. Press firmly and watch for the cloud of shellac being left behind the muneca. Remember to use the paper blot test to maintain a properly loaded muneca. You will need to go over the top 2 or 3 times with full bodying sessions. Now, let the guitar set for about and hour. Next, charge the muneca with shellac, alcohol, and a drop of oil as usual. This time, however, add a very small amount of pumice to the bottom of the muneca. With a drop of alcohol, clear the pumice and begin rubbing over all of the scratches. Press firmly and keep the muneca moving in clockwise and counter clockwise strokes concentrating on the scratches. Reload the muneca as it starts to run dry. You will see the dull areas that are being made by the abrasive action of the pumice. As you rub, the pumice will disappear into the finish. You will be amazed at how fast the damaged areas will smooth out and return to a perfectly smooth surface. If the scratches are particularly deep, it may take 4 or 5 sessions before all of the scratches are gone. If the pumicing does not remove the deeper scratches, you may have to repeat this procedure.

After all the scratches have been repaired, it will be safe to re-level the top of the guitar with 1200 grit wet and dry sandpaper. When complete, add 2 or 3 glazing sessions and spirit off the guitar using only alcohol. Keep spiriting the surface and add a little alcohol as the muneca runs dry. If you are sure that all of the defects are adequately repaired, keep spiriting off the guitar each half hour until there are no signs of oil left on the instrument. At this point you will be ready to polish the guitar to a high luster.

Set 2

Q: I was told that I shouldn't try to work on a guitar at my first attempt at French polishing and that I should use scrap wood instead. What do you advise?
A: The guitar is constructed of a system of curves, corners, slots, large areas, small areas, and angles, all requiring practice to build technique. If at all possible, use a guitar, follow directions, and don't settle for anything less than perfection as you see it. All of our students began their lessons on a guitar and have completed the jobs almost to professional standards. We have made exceptions however, to test a new brand of oil, shellac, or grain filler.

Q: I am a part time luthier and have been French polishing my guitars for about four years. I am getting tired of the guitars being returned for refurbishing because the finish is fragile easily damaged. In most cases the upper bout, where the arm lays on the guitar, is worn with the finish almost gone. Belt buckles and buttons also take their tole on the backs. Somehow I feel responsible and wind up doing the job for almost nothing just to keep my customers happy. I have heard of luthiers who lacquer all but the tops of their instruments. They still French polish the top because the top of the guitar is more important acoustically than the back and sides. Do you agree with just French polishing the top?
A: Yes, if you have the additional equipment that is required or wish to invest in the equipment, it may be a viable option. Many luthiers including us will give their customers a choice between a fully French polished instrument and the hybrid finish. Each type of finish is priced accordingly, with the full French polished instrument being the most expensive. Be aware that luthiers who do apply the hybrid finishes make a concerted effort to choose a finish that is as thin as possible to avoid affecting the instrument's sound. You may want to research the newer and lighter type of polyurethane finishes.

Q: My French polishing goes well for a while then the muneca seems to start leaving particles in the finish. Can you tell me what is wrong?
A: Three things could be happening. First, you may be using the muneca too wet. This will have a tendency to remove shellac and leave minute particles and fibers from the muneca in the finish. Be sure to wring the muneca often and use the blot test. Second, you may be using too little oil. Not enough oil will cause the muneca to stick which will also leave particles of muneca fibers in the finish. Use a bit more oil and see if this solves the problem. The oil can always be removed during the stiffing. Third, your muneca may be contaminated with particles either from worn and loose fibers on the muneca or from particles in the air that have landed on the guitar. Always make a practice of cleaning the guitar and the perimeter of the muneca before each session. You also may want to change the muneca cover when it looks worn or is glazing over.

Q: Sometimes my muneca stops feeding out the shellac and I can't seem to get the cloud of shellac back. Wringing out the muneca doesn't seem to help. I have tried adding alcohol which also doesn't seem to work. What's wrong?
A: The chances are that the fine weave in your muneca is clogged with dried shellac. To avoid the problem, be sure that you are using the right muneca cover. T-shirt material is best and well worn cheaper t-shirt material with a looser weave is better yet. We might mention also that you should always store your muneca in a tight container while not in use. This will help to keep the shellac in the muneca from drying into the weave of the cover.

Q: How important is temperature? Is a paint booth required for French polishing?
A: A paint booth would be expensive. All that is required to French polish is a dust- free area that is kept at room temperature. Shellac always works best when applied at room temperature. A clean, dust-free room is also necessary. Since very little space if required, most French polishers that we know use a spare room or small area in their house.

Q: You mentioned steaming out minor dents in the wood. When you repair or refurbish a guitar's French polish, can you steam out the dents and scratches?
A: Unfortunately heat in any form, especially steam, will destroy any finish- especially French-polish. If you have to strip off all of the old finish to refinish damaged areas or if you are detailing a newly constructed guitar, then steaming will save you a lot of sanding. Otherwise, steaming is not a good idea. If you do occasionally choose to steam out a defect, be extremely careful. The steam can also loosen glue joints.

Q: Are there such things as hardening agents that can be mixed with shellac to make the finish more durable?
A: Yes, there are a number of resins that can be added to shellac which are considered finish hardeners. Copol and Sandarac are two that we have used. Both are resins which are dissolved in alcohol the same as shellac. About one part of each is added to ten parts of shellac.

Q: Why can't you use sanding sealer instead of going to all of the trouble of grain filling with pumice?
A: Sanding sealers were developed primarily for industrial use as a sealing base for chemical based lacquers. They are usually required to be sprayed on and sanded to provide a smooth finishing surface. They do not actually fill the grain unless you spray on at least 5 coats, sanded between each coat. This buildup of thick finish material is exactly what the French polishing process avoids. We have also found that sanding sealers have very poor adhesion properties. After a period of time, areas of the finish will tend to lift and flake.

Q: Is there any way to clean shellac from the cloth used to French polish?
A: Yes, you can boil them in a mixture of water and Borax, wash in the washing machine, and dry. Be aware, however, that most of the cloth will be well worn and the effort may not be worthwhile.

Q: Why can't you just brush on the spit coats of shellac instead of rubbing them on with a muneca?
A: You can but you run the risk of "bridging" the grain and pores in the wood. "Bridging" is a term used when materials do not flow into the grain of the wood. The shellac has poor flow-out properties which causes it to lay over the top of the grain, sealing over the pores. This will create thousands of voids which will resist filling with pumice as it is being applied. As the final finish begins to harden, the finish will tend to shrink into the pores. Wiping the shellac onto the surface will press the shellac into the wood grain minimizing shrinkage.

Q: Is olive oil the only oil that can be used for a lubricant?
A: No, there are a number of different oils that are used in French polishing and are designated as "drying oils" and "non-drying oils". We did not enter into a long discussion regarding oils because the use of oil is pretty straightforward with olive oil currently being favored at the time of this writing. Drying oils such as walnut oil was favored at one time since it combined with the shellac and, when dry, worked as a hardening agent. A few years ago manufacturers began to provide additives, such a vitamin E, which cause problems with the finish. Other additives are contained in many other oil products that also may cause problems such as antioxidants and perfumes. At this time most olive oils have been left alone without the manufactures providing additives. Always read the label and avoid oil with additives.

Q: I am still not too clear as to the difference between "stiffing" and "spiriting". Can you clarify this for me?
A: Stiffing and spiriting are very similar but completed at different times for different reasons. Stiffing is done at the end of each session using only alcohol added to the muneca. A very small amount of shellac is added only if the muneca starts to drag or stick. Stiffing acts to level the ridges and pad marks left by the muneca. Spiriting is usually done after the work has been allowed to dry and harden. Spiriting gets it's name because only alcohol is used with the residual shellac left in the muneca assuring that shellac is not being removed. The purpose is to clean and remove the residue of oil left after the finish hardens and at the same time to polish the shellac to a high gloss.

Q: How long should I let each body session of shellac harden before starting the next bodying session?
A: There is no set rule for hardening time. We might apply two or three body sessions, one right after the other, without stopping. Never apply more than three though. We will then let the guitar set one hour for each session; as an example, one body session for one hour, two sessions for two hours etc.

In Closing
The response that we have receive from our original article has inspired us to expand and improve our web site. We would like to thank every one who has taken time to write to us with there positive comments. It is especially gratifying the hear from the many who have had good success with their projects because of our article. French polishing, like most disciplines, takes practice to master. With the right instructions, at least, there is a place to start. The rest is application and experience. Knowing where to start and exactly how anything is done is usually a mystery until the right instructions are found. The purpose of this article is to open the door and encourage anyone who is interested to learn this fine art. Again, we invite you to write us with your comments and questions .

Bob and Orville Milburn, Luthiers
August, 2001