Expert: Greg Scholl - 8/16/2010

Question
QUESTION:   I am trying to restore the finish on a set of four side chairs. I'm not sure how old they are--possibly from about the 1940's. The finish is shellac. They didn't cost very much--however I've spent a lot of time, effort and some money on tools to repair them.
Regarding the finish, there are areas of wear down to bare wood across the front seat rails, crest rails, and feet. I realize that when there are large areas of missing stain and finish, most people would strip, sand and refinish. However, the reason I bought these chairs was to learn about restoring--difficult to do while on a budget. Anyhow, I've cleaned all four using dawn dish washing detergent and distilled water. I am using Minwax oil-based stain (dark walnut was a match) to color in the bare areas. (I've done one chair so far.) After this has dried completely, I plan to brush on a shellac finish, and then when that has dried, to apply a colored wax with 0000 steel wool. My questions are, will these steps work in your opinion? I did not clean with mineral spirits or Naphtha before I applied the stain to the one chair-- but wish that I had because I am afraid to brush on the shellac for fear that any wax still on it will cause some sort of problem. What could happen? And what do you suggest? Must I use the Naphtha? Also, as I am new to applying shellac, do you think that a one and a half pound cut is about right? How many coats will it take? I realize that each has to dry completely before applying the next. Is it a good idea to lightly sand after three or four of these thinner coats, before applying two more? I read that this is usually better because a thicker cut and fewer coats would be more difficult for a beginner--the article said drips would be a problem. Yet five or six coats seems like it may be too much. Any and all suggestions will be GREATLY appreciated. Sincerely, Melissa

ANSWER: Hi Melissa,It's likely the chairs are finished in lacquer if they are commercially produced furniture...shellac was really not used too much in the 40's, especially by factories, as lacquer was really coming into it's own then....if you take some alcohol and dampen a rag, and hold a finger tip with the dampened rag onto a spot for about 15-20 seconds and then rub the spot with your bare finger, it will be sticky if it is shellac. If it is NOT sticky, it's almost certainly lacquer.Minwax stain should NEVER be used in this type of situation, or any situation where there is remnants of an old finish. It's extremely finicky about drying fully , and it will cause problems, especially with adhesion of a finish. It is ONLY for use on clean, prepped bare wood, ( as stated on the directions).This type of touch up work is done usually with dye stains, as they have several advantages over an oil stain and will not compromise adhesion of the clear coat. Dye stains are tricky to use however, often need to be custom matched to the job, and are not readily available, unless you know where to look.(Woodcarft sells several options). You could use a Gel stain for this type of touch up, but it may not be easy to get an exact color match without buying a few colors and mixing the right color...Gel stains are in a polyurethane carrier, and have good color strength, so they dry predictably, and will seal the wood in preparation for the topcoats. Often though, this type of stain is also not a good solution for the type of work you're trying to do.It also has a long dry time, and on hard woods, like a conventional oil stain, will not stain dark enough, even with multiple coats when compared to a Dye stain. Dye stains dry very quickly (minutes), are easily mixable, especially when using TransTints or another Dye concentrate,(as one can make small batches of custom colored touch up stain quickly and easily),and one can also make custom toners (Dye tinted clears) to enhance the colors as the factories often did, and blend the repairs as well. I would caution against cleaning any wood furniture with a water solution, (be it TSP, dish Soap, or whatever), as water will raise grain and swell wood fibers, and has a way of getting into stiles, rails, panels, and other joints where you can't get it totally dry immediately.Soaps can leave residues unless the surfaces are flooded with clean water, something you definitely DON'T want to do with a piece of fine furniture... Mineral spirits is usually a good choice, as it cut's wax, grease, grime, etc., without the possibility of affecting the wood, and it will also give you an idea of what the finished area will look like when wet with it...use 000 or 0000 steel wool and dip it into a container of mineral spirits, and work in small areas, drying with clean rags as you go. Pay attention to the rags and you will know when you're getting the area clean, as the residue will stop appearing on the rags.Naptha dries faster, but it's also more toxic, and there's really no need for it. Shellac can be challenging to work with, it dries SUPER fast, and can have issues with touch up work, especially if there is wax or grime residue as you've pointed out.It will wrinkle or lift on application of a successive coat in these cases, and it can be very frustrating at time...padding it on with a "rubber", (a French polishing term"), is better, but not practical sometimes on a chair with turnings or intricate areas....spraying is also a good way of applying shellac. It also has a shelf life, and old shellac can also present a few issues, most notably not drying as hard as it should.It's best to mix your own, from dry flake, and many varieties can be sought and used. I keep a Button polish,Garnet, Blonde, and Super Blonde on hand at all times, as they all have differing colors, and 'looks' depending on what type of wood, or situation they're being used in.And in restoration work, it's important to use Dewaxed shellac. In most cases when 'touching up' or restoring a finish, just a few coats will be warranted, but again, that will depend on the circumstances at hand...If these chairs are shellac, I would be surprised, but it's not unheard of, especially if someone refinished them at some point, but if you're going to get serious about this type of finish restoration, you're going to have to learn about lacquers, Dye stains, toners, and the related materials, because the majority of furniture, like chairs, produced in the last 85 years or so will be lacquered. Luckily, there is a large supply oif touch up aerosols and materials designed for touch up work from Behlen, Mohawk and others, but knowing what to use, and how to use it takes knowledge and experience gained over time....and it's not something that one can just decide to do and pull off easily without some serious study and work. As you can see, trying to teach in a forum like this is not possible, (without writing a book, essentially), but if I can help further, I'm here. Much information and study materials are on the web, and at the Library, and many localities offer classes, seminars,etc. through Adult Ed., or stores like WoodCraft on these topics, and Taunton Press has several excellent books, videos, etc. from the likes of Jeff Jewitt, Bob Flexner, etc. on finishing, restoration, touch up, etc. Hope that bhelps a little to point you in the right direction- regards- Greg

---------- FOLLOW-UP ----------

QUESTION: Hi. Thanks so much for having taken the time to answer my questions. I had already used the type of test you mentioned to determine the type of finish on my chairs. Denatured alcohol made the finish sticky. I wondered what a drop of lacquer thinner would do, so I tried that too. It turned white. The next day the spot was dark again. It was explained to me later on that the acetone reacted with the shellac, and as the solvents in the lacquer thinner evaporated the whitish haze disappeared. So I definately have a shellac finish. ...You mentioned that oil-based stains should never be used when an old finish is present, that the stain may not dry properly. And that the shellac will not adhere to it. Wow... I really wanted to use shellac over the oil-based stain I've already used on the one chair. And then follow suit with the others. So, I'll be brave and ask, Did you mean that shellac will NEVER adhere and turn out right when applied over an oil-based stain? Or did you mean that when the stain doesn't completely dry, that the shellac won't adhere? It's been 8 days since I applied the stain, and it's definately dry. Dare I try to apply the shellac? I already bought the dewaxed flakes. I haven't mixed them with the alcohol yet. The information you gave about using dye stains sounded great. About the dye concentrates... Are they in liquid or powder form? What do you mix them with? What do you use to mix dye tinted clears? Where can I buy these concentrates? Are they expensive? I really do want to develope restoration skills. Thanks so much for your help. Sincerely, Melissa

Answer
No, ....shellac will stick to almost anything, especially dewaxed shellac...but the oil stain may not stick well to remnants of an old finish, even if it dries ok, it does not make a good bond, and you're always at the mercy of the first coats ability to adhere to the surface, no matter what you apply over it.Shellac works well over an oil stain, but it's the stain layer you've got to be concerned with.These stains are NOT recommended for this type of work, (always read the labels carefully),and the fact that they can take DAYS to dry is a huge minus, and doesn't mean they're adhered to what you put them over.They can also lift when you go to apply a solvent based finish over them (shellac, varnish, etc.).They're really designed for bare wood. Dyes can come in Concentrates (both powder and liquid and fairly expensive,ie:Transtints and Transfast), and premixed, ready to use (ie:Behlen SolarLux, General waterborne Dyes, not so expensive)...the concentrates can be used in almost any medium,including finishes (toning), stains (changing or deepening stock stains or making custom stains),etc., but they're unforgiving if you make an error, and again, one has to know the proper use, mixing chemistry, and application parameters in which to use them. I'm enclosing a link to Homestead finishing, Jeff Jewitts excellent site, and there he has a vast amount of information and supplies for purchase, including many different dry shellacs, additives, stains,Dyes, finishes, how to's, and even a forum where people ask questions and share knowledge.....spend some time there and poke around...it's a great resource.Touch up lacquer toners are available in pigmented and Dye based formulas, and of course the sealers and clears are also available in aerosol form (spray cans), which are perfect for touch up work and even full projects..but there is a myriad of products available, and one needs to know a bit about them and where and in what situation to use them.I buy Mohawk products from Pond Cove Paints in Portland, Maine.

http://www.pondcovepaint.com/content/page/catalog_list/cat/73/Mohawk_Finishing_P

This is a pretty steep learning curve and really comes through experience, research,learning, and using all of these various materials and techniques....it takes years, like any worthwhile endeavor.

http://www.homesteadfinishingproducts.com/index.html

once at the home page, peruse through the headings on the left of the page for supplies, then click on "Articles", "Dye FAQ's", and visit the "Forums"....I'm sure you could spend hours there, and I would advise bookmarking it so you can come back, along with us at AllExperts :-)......in the "Articles" section, there is an excellent tutorial on doing an Antique Maple finish, which is a good example of how a multi step, deep finish is built using dyes, shellacs,glazes and then various topcoats, and a fantastic article on shellac, (be sure to read about application methods where he touches on "padding")

http://www.homesteadfinishingproducts.com/htdocs/shellac.htm

.....best of luck,... and I'll be here- Greg