The key terms concepts and phases in finishing refinishing furniture.
STRIPPING
STRIPPING: An existing finish can be removed by the stripping process. Stripping can be done by methods of hand stripping, flow-over stripping, dipping tank soaking, or vapor booth. We use the flow-over method for maximum safety and control. The process involves putting the wood item in a tray and circulating a liquid stripper fluid over the item using an air operated pump to drive the fluid through a hose with a brush on the end. It is cost effective because the chemicals can be reused. It allows maximum control because of the hand application and brushing.
NEUTRALIZATION: After an item is stripped the chemicals that were used must be neutralized and removed, along with any remaining particles of finish. We use a high-pressure low volume water rinse system, much like the spray wand at the car wash. The item is then air-dried.
POST-TREATMENTS: There are several special actions that can be taken after an item is stripped and neutralized. They include applying a dye-out to remove old deeply penetrated dye stains frequently found on mahogany stained items. Another is wood lightener that whitens the wood to a more original state, which is great if you want to re-stain a very light darkness. A final application is wood bleaching which lightens badly stained areas within reason. Bleaching that is performed irregularly often results in a poor result.
REFINISHER: As an alternative to stripping, which removes the old finish and stain down to the raw wood, there is a product called refinisher. This chemical reliquidfies the old finish and allows most of it to be removed by lifting it off with steel wool pads. The original stain coloration remains, along with the patina of the remaining small percent of finish. Since this works best with old varnish finish, the new finish must also be varnish or tung oil. The original coloration can not be changed and the new darkness will be less than now because of the discoloration that was most likely being caused by the deteriorated finish.
WOOD PREPARATION
SANDING: The machining of a new item normally includes only the final sanding processes that could be accomplished with large machinery or belt sanders. To fully prepare an item for a quality finish, final sanding should more adequately be accomplished with hand applied pad sanders and hand sanding. The final grit of such sanding is crucial to the final appearance of the item. For furniture grade items the final sandpaper to use is 180 grit in order to obtain the maximum final appearance. For cabinet grade items the final sanding is done at 150 grit.
WOOD INDENTATIONS: It is possible on an older item that minor dents and dings will be discovered after stripping that need to be removed. The process applied is to steam the compressed wood fibers to cause them to re-expand, thus allowing the final sanding.
VENEER IMPERFECTIONS: When reworking older furniture that contains veneered surfaces, it is frequent that the age has attacked the hide glue and caused areas of the veneer to lift or bubble, especially once the old finish has been removed. The areas must be re-adhered by reactivation of the old hide glue with heat, re-adhering with injection of new glue, or patch replacement of broken or missing veneer.
WOOD FILLER: In the fabrication or repair of an item it is possible that minor cracks, nail or staple holes need filling. In many older items the old finish hid these faults. We have tested over 20 types of wood fillers and use a professional brand that best matches the final wood species and takes the stain application the best.
SURFACE INSPECTION: Furniture items go thorough a process of wetting the flat surfaces with lacquer thinner in order to inspect closely for minor machining or natural wood imperfections that have been missed in the final sanding processes.
STAINING / COLORING
PIGMENTED WOOD WIPING STAINS: These are more commonly known as penetrating oil stains that apply and leave pigment color in the wood grain. They bring out the natural beauty of the wood grain based on the species of wood involved. We use a professional line of stains that are colorfast and natural looking. They are defined as colors based on wood species, such as walnut that is brown or mahogany that is a deep reddish color.
DYE WOOD SPRAY STAINS: These are more commonly applied only by spray application. The dye soaks into the wood much like ink into a blotter depending on the amount applied. The result is a more even coloration and darkness which de-emphasizes the grain variations. They allow the attaining of the darker ranges of coloration. They can also be used to even out the uneven grain results from pigmented wiping stains or Mother Nature's growing of the wood.
PICKLING: This is the process of applying a highly pigmented oil paint by spray and then wiping it back to leave the pigment, usually white, primarily only in the grooves of coarse open grain woods such as oak, ash, etc. It does not work well on smooth grain woods such as maple or birch.
MIST COATS: This is the process of applying a pigmented wood wiping stain, usually in the white coloration of ash, and wiping it back like a normal stain application, but then going further and reapplying a thin misted coat of stain that dries on the surface of the wood.
COLOR MATCHING: It is commonly thought that to match another stain coloration, clarity or darkness that the stain should be pre-mixed to that target. Such is not true. The best process is to apply the lightest stain color and then to subsequently apply darker and darker stain colors to reach the desired target. It must be recognized that frequently we are trying to match another finished item where the other older topcoats are causing lack of clarity or discoloration from age.
SOLID COLOR LACQUER/OIL PAINT: Either oil paint or color lacquer can be applied to totally mask the grain variations. The texture of the original wood will still be apparent. This means that most solid color finish is applied over smooth grained woods, such as birch, and great effort is required to eliminate any imperfections. It also means that if solid color is applied over a coarse grain wood, such as oak, that the irregular grain texture will remain and add another visual feature.
ENAMEL: At this time the paint industry uses the term "ENAMEL" as a generic term referring to the hardness of a paint. Resins are used in the paint to give it a harder finish. SO the term enamel can be applied to Oil or Latex, Interior or Exterior, Flat or Gloss.
FINISH SEALING & PRIMING
SEALER: The application of a lacquer sealer by spray methods allows the sealing in of the coloration, wood fibers, and wood pores. The sealer has a high rate of solids content allowing for easy scuffing.
PRIMER: The application of a lacquer primer, specially formulated to control for wood resin, is applied by spraying in order to seal the wood fibers and prepare the wood for final top coats.
SCUFFING: After the application of a sealer or primer, minor wood fibers are raised and must be removed. The process is called scuffing. We do it by hand sanding with 220 to 320 grit sandpaper and close visual inspection.
SURFACE TREATMENTS
GRAIN FILLING: This is a process of hand applying a special paste wood filler to open grain woods such as ash, oak, mahogany, or walnut in order to fill the grain texture and obtain a more glass smooth finish. The gloss level is a separate question addressed by the gloss level of the topcoats of finish. The wood filler must be sanded back smooth after application. For a really smooth finish, several such applications may be involved, but only one application is considered to be standard. The paste wood filler can be either a natural wood color or pre-colored.
GLAZING: This is the process of applying a non-transparent pigmented color on top of the stain and sealer coats in order to highlight a carving area or some other aspect of the wood furniture design. The glaze is applied and wiped back to leave those areas desired. As an alternative, it is the process of applying a faux grained finish to the non-wood edges to some table tops etc.
COLOR TREATMENTS
TONING: The aerosol or spray gun application of pigmented stain contained in the topcoats of lacquer is called toning. It helps to hide grain variations and other blemishes.
SHADING: The aerosol or spray gun application of dye stain contained in the topcoats of lacquer is called shading. It helps to hide grain variations and other blemishes and to attain darkness not previously obtained. The dye stains are usually an aniline powder that is mixed in lacquer, alcohol, water, or oil.
FAUX FINISHES
MARBLIZING: This is the artistic process of applying a solid color base coat which then has hand applied special top coats in a form that ends up looking like real marble. The final result is normally protected with a clear top- coat.
FAUX STONE: This is similar to marblizing, except the end result looks more like granite. Different background colors and accent colors can be used.
TOP COATING
APPLICATION METHOD: We exclusively use air spraying which is the top quality approach. No runs, no sags, no orange peel, or thickly layered coats that look plastic. Various types of finish topcoats can be applied by one or more of the following methods: rag, brush, airless spray, or air spray. Spraying almost always gives a much better result than the other methods. Airless spraying applies the finish liquid without mixing with air and that results in a thicker coat that might have runs, drips, or orange peel effect. That is okay for household trim but not fine furniture.
GLOSS LEVEL: The range of gloss levels is defined as flat, dull, satin, semi-gloss, and high gloss. Most items are finished at the satin or semi-gloss level. High gloss requires extra effort. The application of the topcoat is done from lower to higher levels of gloss, based on the end results wanted. The normal application is at least two sprayings of the topcoat lacquer, beyond the sealer coat. An application may really include more than one coat at a time due to recovering of surfaces from different directions. It must be recognized that gloss level does not include the question of wood smoothness.
LACQUER FINISH: We use a water white lacquer so that there is no disruption of the natural or stain colors previously applied or from discoloration over time caused by sun. In addition, we use an acrylic lacquer so that the final finishes are technically flexible to help guard against water, alcohol, and chipping to the maximum degree possible. The advantage of lacquer is that it sprays wonderfully, dries quickly, does not discolor, and can be repaired.
SPAR VARNISH: When the wood item will be exposed to direct weather and wetness, the ideal finish is a spar varnish for maximum water penetrating control. The normal gloss level is high. Since the finish dries very slowly, great care must be taken to keep airborne dust from settling on the item.
DANISH OIL: In lieu of applying a stain/coloration and the application of topcoats, a penetrating Danish oil hand rubbed finish can be obtained by soaking the item with Danish oil and rubbing it into the wood and grain with high grit sandpapers thorough several applications. This process brings out the beauty and texture of the natural wood.
POLYURETHANE: A chemical enhanced version of varnish that is designed to be hard, and that can be brush applied or sprayed, is a recently developed newer finish. It is commonly misunderstood to be waterproof, which is not true. It also has the draw back of being very difficult to ever remove, hard to repair, and deteriorates under the sun. We do not usually recommend such a finish. Our acrylic lacquer is superior in every way.
TUNG OIL: This hand rubbed surface finish will go on just about anything. It is therefore sometimes used in finish restoration to get a reasonable finish build and gloss on top of whatever worn out finish already exists. It should be used with caution since it is not particularly protective or durable. It is best suited for something like a mantle clock that will receive little handling.
POLYESTER FINISH: In more recent years we have seen two-part catalyzed polyester finish on specialty items such a high gloss piano, art-deco design furniture, and imported exclusive items. It, from a practical standpoint, can not ever be stripped or custom applied. It requires very special techniques to even repair. Its benefit is suppose to be its extreme hardness and clarity.
FINISH RUBBING
RAISING GLOSS SHEEN LEVEL: The process of polishing or rubbing the final sprayed top coat of finish to a higher sheen can be accomplished by power buffing the finish with specialty rubbing compounds and lubricates. It is a very time consuming process and usually only applied to finishes that have some mars that need to be eliminated.
LOWERING GLOSS SHEEN LEVEL: The process of lowering the final sprayed topcoat of finish to a lower sheen can be accomplished by hand rubbing the finish with various abrasives and lubricates. The most common might be sanding with 1200 grit down to 400 grit special sandpapers.
SCUFFING OUT: If the current finish is sound and thick enough, but has minor scratches or faults, it is possible to grind it back with very fine grit sand papers and then to re-polish it to the desired sheen levels. This works well only with physically finishes in sound condition.
FURNITURE WAX: The final finish can be protected, from abrasion and water to some degree, with an application of a paste wax. Several initial applications are normally required, but regular re-applications are less frequent. Maintenance should normally be done only with a damp cloth to lift any dust. Furniture polish should not be used on top of paste wax because it will simply remove the wax protection.
FURNITURE POLISH: The final finish can also be protected with application of a furniture polish. Several applications are normally required, and more regular reapplication is the norm. Less effort is involved. The depth of the protective coating is less and therefore less protection is provided against abrasion and water penetration. Polish should never be applied over a wax.
FINISH REPAIRS
FINISH CLEANING: The build up of wax or polish, and the related normal accumulation of household soiling, can be cleaned with special furniture finish cleaners. Carefully used, naptha will accomplish the same task. If the existing finish is not too deteriorated, the cleaning will allow the reapplication of new coats of wax or polish. The result will be a rejuvenated looking finish.
WATER RINGS: If the current finish is sound, and not shellac, it is usually possible to remove water rings with the special application of denatured alcohol. It is also possible that abrating back will be required, after which the finish sheen will have to be re-established. This would not remove any discoloration from plant soil seepage.
FRENCH PADDING: After cleaning the finish to remove contaminates, the process of French padding can improve the finish. This is really the process of applying very thin coats of shellac to the top of the existing finish, no matter what it was, to rebuild a finish. The final sheen is normally toward a high gloss, but it can be rubbed back as required. Because shellac can be easily damaged by water, it is not good to use the process on dining room tables.
CARPENTER'S CRAYON: Minor holes or cracks can be filled with a hard pre-colored crayon that reasonably matches the existing finish.
BURN IN STICKS: Larger surface dings or cracks can be filled by melting solid colored sticks of lacquer or varnish with a special hot knife and dripping the fluid into the blemish, after which it must be sanded flush, polished, and top -coated.
DRIP-INS: When an existing finish has a minor dent or ding, lacquer or varnish can be dripped into the cavity and allowed to dry. It is then abrated back to the flush level and polished to obtain the desired sheen. An advantage is that the finish remains transparent.
At The Wood Works we specialize in all aspects of finishes for fine furniture.
This paper was originally written in 1992. When updated in 1998 it seemed amazing how little it had changed.
Of all the possessions we accumulate in life,
fine furniture is one of the few items
that will last several times longer than we will.
When we buy or inherit old or fine furniture,
we therefore assume some responsibility for its care
so that future generations won’t be denied the pleasure of using it.
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