Refinishing basically involves three procedures: stripping the old finish, sanding and preparing the wood, and applying a new finish. Preparation greatly influences the quality of the refinishing job, and the amount of work involved depends on the type of wood you're refinishing and its condition. Traditional, time-tested finishing techniques and high-tech methods involving spray equipment are available, along with many in-between alternatives, so you have plenty of room to innovate.
Use Methylene Chloride Stripper
You can use soy-based strippers to remove many furniture finishes, but they work slowly and aren't as reliable as those made with methylene chloride. If your furniture is painted or finished with varnish, choose a product identified as "paint stripper," which has a higher concentration of the caustic chemical than furniture finish stripper. Brush the stripper on with a paintbrush; wait for the finish to bubble; and then scrape it off with a paint scraper before it dries. If you're refinishing furniture with carvings and turnings, you'll need a sharp implement to get in crevices -- a dental pick works well for this. Scrape lightly to avoid damaging the wood.
Sanding and Wood Repair
Before you sand, wash the wood with clear water to neutralize the stripper; wait until it dries; then repair gouges and holes with stainable wood filler. To remove all the stripper residue, remove the raised grain caused by the moisture and generally smooth the wood for finishing, sand with progressively finer sandpapers, starting with 100-grit and finishing with 150- to 180-grit, depending on the wood. If desired, you can work up to much finer grits, but getting the surface too smooth may affect how well it accepts stain and/or protective finishes.
You can use power sanders to speed up this tedious job, but be careful not to overdo it and remove too much wood or muddle fine details. Random orbital sanders are best for large areas and fast removal of old finishes (and wood). Detail sanders are ideal for tight spots and ornamentation. Always sand with the grain of the wood – not across the grain – and keep the sander moving at all times. Some sanders can leave fine scratch marks in the wood that show up when you stain; minimize this by sanding with progressively finer grits. It's usually a good idea to do a final hand-sanding after using power sanders.
Wood Staining Tips
Certain wood species, including birch, maple, pine and cherry, are notorious for accepting stain unevenly and blotching. One way to avoid this is to paint the bare wood with wood conditioner, which deposits a layer of paraffin in the grain that seals the wood. Some woods, such as knotty pine and birch, have such large grain variations that professional refinishers prefer to seal them with a coat of shellac instead. After sealing the wood, apply a single coat of oil- or water-based pigmented wood stain, let it soak for about five minutes, then wipe off the excess with a rag, wiping with the grain to prevent streaking.
Nitrocellulose and acrylic lacquer, applied with spray equipment or an aerosol can, are two of the most common furniture finishes. When using either one, it's best to build up the final finish with a series of thin coats, sanding each one lightly with 320-grit sandpaper before applying the next. If you prefer a more traditional finish, wipe on two or three coats of penetrating oil, sanding between each application, and polish the final coat with furniture polish or wax. Oil finishes allow the natural qualities of the wood to shine through, but they need more maintenance than lacquer finishes, and they aren't as resistant to spills. Another option is wiping varnish, which is both easy to apply and highly durable. The final result is a hard clearcoat, similar to lacquer, that doesn't need waxing or polishing.