Removing the Old Finish
When refinishing furniture, you must do the most unpleasant part of the job first. Removing the old finish can be a cumbersome and messy task. For a while early in the process, until you start getting down to the wood underneath the mess, you may feel that you have completely ruined the piece. Have patience. Once you finally get to the point of final sanding the wood, you will have graduated from making a mess to creating a masterpiece. When you’re finished, you’ll be proud of what you were able to create.
You can remove old paint and varnish in a couple of different ways, primarily by sanding and by the use of chemical strippers. Heat guns can also be used for stripping, and are sometimes used as a supplement to the other methods in the removal of a particularly stubborn finish.
Sanding is a good method only if you have good sanding equipment and are experienced in the use of such equipment. If you are trying to remove an old finish by hand sanding or with a common orbital finishing sander, you’ll work yourself into a puddle and waste a lot of sandpaper. On the other hand, belt and disk sanders can remove finishes quickly, but since they are capable of removing so much material, you must be very careful not to disfigure the piece by sanding too deeply. It is also difficult to sand varnish from round or decoratively curved areas such as turned table legs.
Chemical strippers, commonly called "paint strippers," are an effective means of removing paint and varnish from wood furniture or projects. Using these chemicals is probably the fastest and easiest method for most people. Despite what you may read on the back of a can, if you want to do a really good job, some sanding will still be required after the old finish is removed by the stripper.
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Chemical strippers or "paint removers"
As useful as they are, chemical strippers can be bad news if used improperly. Treat them with care--use adequate ventilation, rubber gloves and eye protection when using these substances. After all, they are designed to soften, peel and blister paint and varnish--you don’t want them to do the same to your skin, lungs or eyes. Always follow the safety recommendations on the container.
Use methylene chloride based strippers which require "no cleanup" or that will "wash away with water." Statements similar to these will be on the label. The "no clean-up" type stripper may leave a residue which must be sanded away. Residue from the "wash away" type can be removed by rinsing with a garden hose. Hot water with some Spic-And-Span, is a very effective rinse just by dipping the steel wool in it and scrubbing. Be aware, however, that water will swell the grain of the wood, requiring that the raised grain be lightly sanded. If you want to keep the patina in the wood, you will need to rinse the stripper off with mineral spirits or my favorite, lacquer thinner. You will need good ventilation for this, plus it is a major fire hazard.
There are some new strippers on the market that use a different chemical that doesn't burn your skin. Some smell like oranges and don't require as much ventilation making them more practical for use in the home. The downfall to these, is that they require a lot of time since they are very slow working, and cost quite a lot more.
Strippers come as liquids, or in thicker formulations referred to as gels, semi-pastes or pastes. Liquid strippers are only good for horizontal surfaces. For vertical surfaces, the thicker strippers are able to hang on better.
In general, the rules for using chemical strippers are as follows. Products may differ, however, so always follow the manufacturer’s directions for the product you choose.
Apply stripper to a manageable area. Put on a thick coat, and do not disturb it once it is applied.
Let the stripper sit for the time recommended by the manufacturer. Be patient and let it do the work for you. After the recommended time, test the finish with a putty knife. If it is soft and the putty knife cuts through to the wood, you are ready to go to the next step. Do not wait so long that you let the stripper dry.
Remove as much paint or vanish as you can with a scraper or putty knife. (Round the edges of your scraping tool to prevent it from gouging the wood.) Follow-up with #2 grade steel wool. Soaking the steel wool in the stripper may help remove stubborn spots. Some finishes, particularly enamels, will require multiple applications of stripper to get the job done. For removing paint that is imbedded into the wood grain or other detail, a soft brass bristled brush works well for scrubbing it out once it has been softened by the stripper
Once you have removed as much finish as possible with the stripper, scrapers, and steel wool, follow the manufacturer’s directions for cleaning the stripper from the wood. Some products require that the stripper be removed with lacquer thinner or mineral spirits, while others should be rinsed with water. Then, let the piece dry thoroughly--at least 24 hours.
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Preparing the Wood
Now that the piece you are refinishing is free of the old finish and has had time to dry, you are ready to sand the wood. Depending on how good a job you were able to do with the stripper, you may not have a lot of sanding to do. Just start with 120 grit paper to clean off any finish which may remain and to smooth out any bad places in the wood. Then smooth the whole piece down with 220 grit paper. Finishing sanders--the orbital type--are particularly well suited to quickly achieving a uniform smoothness. When sanding by hand, be sure to sand with the grain. On flat portions , especially the tops, you will need to do your final sanding with your sand paper wrapped around a flat sanding block.
The quality of your final finish will depend largely upon the care you take when sanding. No amount of stain and varnish will correct a bad sanding job. In fact, stain will emphasize any rough places, swirl marks or other defects. Take the time to do a good job. It’ll make a big difference.
Filling the Grain
Some woods have a tight grain and don’t require grain filler. Others, however, like oak, walnut, and mahogany, have a open grain structure that must be filled if you hope to achieve a smooth, even finish.
Grain filler comes as a pigmented paste, and is available in a range of colors. If you want to emphasize the grain of the wood, select a color that contrasts with the natural color of the wood (or the color you intend to stain it). If you want to de-emphasize the wood grain, select a color that closely matches the anticipated finish color of the wood. You may want to test your planned finish on a piece of a similar wood; use the filler, stain and final finish just as you plan to do on the project. This will let you see if you are on the right track.
Grain filler may be applied before or after the stain. Consult the labels of the materials you are using for their recommendations. If you don't want the filler changing your stain color, seal the wood with a light coat of sanding sealer or shellac first.
Use a rag or stiff paint brush to apply the paste filler. Work it into the grain and let it dry as instructed on the product packaging. Then, remove the excess filler with a plastic scraper or a smooth, rounded edged-putty knife held at a slight angle to the wood surface. Be careful not to the damage the wood. Allow the filler to dry completely and lightly sand with the grain.
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What Kind of Stain Should I Use?
If you are refinishing furniture, you’re almost certainly going to be using stain to achieve the color you desire and to reduce the contrasts between any different wood varieties which may have been used in the construction of the furniture. There are several different types of stains and dyes which may be used to color wood. We’ll discuss the basic types most easily used by less experienced wood finishers.
Liquid oil-based stains penetrate into the wood without raising the wood grain. They are permanent, and when properly used, yield very good results. The color can be darkened by multiple applications and by lengthening the time the stain is allowed to penetrate into the wood, thereby allowing reasonable color control. These stains do, however, have a strong odor and must be cleaned up with mineral spirit type solvents.
Liquid water-based stains are environmentally more friendly than traditional oil-based products and are rapidly gaining acceptance. As with oil-based stains, you can deepen the color of the stain with multiple applications. Water-based stains are convenient to use and require only a soap-and water cleanup.
The major drawback of water-based products is the fact that they can raise the grain of the wood. To minimize this possibility, dampen the wood with a moist (not dripping) rag. Allow the wood to dry completely, and finish sand again with fine sandpaper. Then, repeat the process. This conditions the wood to accept the water-based products with less raised grain.
Unlike liquid stains, gels are thick. They are usually oil-based, and allow great color control because of the thickness of the stain. This makes them well suited for using on pine, cherry, maple, birch, and other woods that don't take a liquid stain evenly. They do not swell the wood grain, and cannot run like liquid stains. They do, however, require more wiping to get all the excess stain off of the wood. They are also more expensive than liquid stains.
One Step Stain/Finishes
One step stain/finishes are popular because of their ease of use. After all, the color and finish are applied to the piece at the same time, eliminating several steps and possibly several hours of work. It is more difficult, however, to achieve a very good finish with these products. The finish itself is tinted, so the color lies on top of the wood instead of being absorbed into it like penetrating stain. Thicker areas of finish will therefore have more color than thinner areas, and any brush marks against the grain (or other surface imperfections) will be more evident in the final finish. Also, these finishes are less transparent and may obscure desirable grain characteristics. One-step finishes are appropriate if speed and convenience are more important to you than the final look of the finish on your furniture. I normally don't recommend these at all unless you have a way of spraying them on.
Always follow the manufacturer’s recommendations for the product you’re using. In general, however, liquid stains are applied with a rag or brush and allowed to penetrate into the wood. Try to always apply the stain with the grain. In general, the longer the stain is allowed to penetrate, the darker the color will be. This only works to a certain extent, however. The excess stain is then wiped off with a clean rag and the piece is allowed to dry. If a darker finish is desired, these steps are repeated.
Gel finishes are applied with a rag--rubbed on or brushed on, then wiped off as necessary to achieve the desired color and consistency.
For best results when using water-based stains and finishes, follow the tips presented in water-based stains.
Applying Sanding Sealer
Applying sanding sealer is like priming the wood. The sealer reduces the tendency of some woods to absorb stain unevenly, thereby creating a blotchy appearance. Sealing end-grain prevents the wood from absorbing too much stain and creating very dark areas. Sealer can also be applied after staining and filling to reduce the number of finish coats which will be necessary. Sanding sealer is unnecessary, however, under penetrating oil type finishes such as Danish and tung oil.
Sanding sealers are available commercially, or you can create your own by thinning the material you intend to use for the final finish with an equal part of the appropriate thinner for that product. For example, a 50-50 mix of polyurethane and mineral spirits would make an appropriate sanding sealer for polyurethane.
Apply a heavy coat of sealer to your project, and allow it to soak into the wood for a few minutes. Then, wipe off any excess with a clean rag. Allow the sealer to dry completely before lightly sanding with fine (360 to 400 grit) sandpaper.
Other shellac and lacquer type sealers require to be sprayed on with spray equipment or spray can.
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The Final Finish
Your choice of top-coating is a matter of personal preference. Penetrating oil finishes are easy to apply and look great with a soft, natural appearance. They afford less protection, however, than varnishes or lacquer finishes. Polyurethane creates a hard, very durable finish, and is now available in a range of glosses. High gloss polyurethane has an unnatural plastic appearance, however, which may be ideal for floors and bar tops, but inappropriate for use when refinishing fine furniture or an antique. Water-based polyurethanes are very easy to use and are environmentally friendly, but they suffer from the same plastic appearance as other polyurethanes, and they also do not lend that soft amber tint to wood which is common with traditional finishes. Lacquer gives a durable and luscious finish, but requires more skill and effort to apply. Your decision about which finish to use will depend both upon your confidence level, and the piece you are finishing.
Water-based polyurethanes are becoming very popular because they are easy to use and are environmentally friendly. They do require a different finishing technique, however. Before applying the finish, rub down the project with a damp cloth. Allow the wood to dry and then sand to remove the raised grain. You may want to do this a couple of times to reduce the tendency of the water in the finish to raise the grain when it is applied. (This should be unnecessary if you’ve already used this technique when applying water-based stain.)
If you've never used water-based polyurethane before, don't be alarmed by the white milkiness of the product as it is applied. It will quickly dry to a completely transparent clear. Unlike solvent-based finishes, it will not lend an amber tint to the wood--which could be a positive, or a negative, depending on what you are trying to accomplish. Water-based polyurethanes also dry more quickly, requiring less time between coats.
Polyurethane is an extremely durable finish that is resistant to both water and alcohol. It is available in a range of gloss finishes to help you achieve the look you desire. When using satin or semi-gloss formulations, be sure to stir the product well to keep the flattening agents in suspension. Avoid creating bubbles when stirring and when applying with a brush. After loading the brush, tap it lightly against the side of the can instead of dragging it across the lip as many people have a tendency to do.
Brush polyurethane with the grain in long, overlapping strokes. Apply several thin coats, sanding in between with 320 grit paper. Sanding between coats is necessary with polyurethane--the coats do not react with each other chemically, so each additional coat must be able to physically adhere to the previous one. It’s not easy to stick to something as slick as polyurethane!
One of the most common mistakes people make when trying to use polyurethane (and many other finishes as well) is trying to apply too thick a coat. This can cause running, wrinkling, and sagging, and is a sure way to mess up your finish.
Lacquer can be used to achieve a beautiful finish. In general, however, lacquer is considered more difficult to apply than other clear finishes because it requires several coats with sanding in between. It dries very quickly, and is usually sprayed rather than brushed. It cannot be used over paint or other top-coats since it will soften and lift the finish. Also, since each coat of lacquer softens any underlying coats, it will not fill imperfections as easily as polyurethane.
For the best finish, lacquer should be sprayed, which some do-it-yourselfers may not have the equipment or experience to do. There is at least one product available (Deft) which combines a lacquer base with a sealer in an easily used topcoat which can be sprayed or brushed. If you use a brush, work quickly and apply lacquer with the grain using a good, natural bristle brush.
A properly applied lacquer finish is a thing of beauty worthy of the finest furniture. A hand rubbed lacquer finish has a deep, soft gloss and does not have the plastic appearance of many polyurethanes. The final coat can be rubbed out with 0000 steelwool and paste wax, or it can be polished with polishing compounds for a mirror finish.
Penetrating Oil Finishes
Penetrating oil finishes are easy to apply and produce handsome results. ">Tung oil, Danish oiland Antique oil finishes fall in this category. They are good choices for antiques or fine furniture which will not be subject to a lot of wear and tear. Choose another type of finish if extreme durability is a requirement.
Basically, these finishes are applied to the wood, allowed to soak for a certain amount of time, and then any excess is removed by rubbing and buffing with a rag. The rubbing also forces more oil into the wood. Several coats are applied.
Small scratches and defects can be easily repaired by simply sanding the defect, and rubbing more oil finish in the affected area. The entire finish can be renewed periodically by rubbing in an additional coat. It is also good idea to use paste wax on furniture finished using penetrating oils. The wax will give additional protection while complementing the appearance of this finish.
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