Two Options for Finishing Your Next Masterpiece
In a small shop we need to find finishing techniques that are repeatable, resilient, inexpensive to buy and apply, but will also give top quality results. This article explores the use of shellac, a great natural product that offers incredible results using a relatively easy padding technique. It also looks at a mixture of oil and varnish that increases resilience and adds a deep warm tone to your work.
The tough thing to accept in woodworking is that no finish is completely waterproof. Finishes also suffer when they come into contact with excessive heat, like that from a dinner plate or coffee mug. Therefore, it is important when considering a project to think about using the right finish for the given application. If making a piece that is seldom handled, like a showcase, then you can take advantage of the stunning beauty of a shellac finish. If you are looking at making a coffee table, you definitely cannot consider shellac but may opt for an oil and varnish mixture instead. Both finishes are simple to repair, which is a key consideration because, inevitably, the furniture will see some wear and tear. Remember when you deliver the piece to the recipient to make a nice card that explains how to take care of the finish.
I often pre-finish parts of a piece before glue-up. Both of these finishes lend themselves well to this technique. During the last dry fit, I apply wax around the joints to repel glue squeeze-out and then complete the final glue up. After final assembly, I clean the joint with either a sharp plane blade or a scraper and apply a final coat of finish to the assembled piece of furniture.
Finishing can be very complex, if you allow it. In a small shop we need finishes that are easy to apply, easy to repair, and those that don’t require exhaust systems. Both of the finishes in this article are applied by hand. Dust is not an issue with either finish; the steel wool used after each application to planarize the surface also acts to remove any dust that has landed on the surface. These are good, reliable finishes that give you the choice between the delicate beauty of shellac, and the durability of oil and varnish mix. The techniques are easy to learn and master, so there is little downside to these finishes.
It’s best to buy shellac flakes then mix up enough finish when you need it. Shellac has a short shelf life after it is mixed.
Fold in the Corners
To make the “pillow” for applying shellac, start with a piece about 12" square. Fold the corners in then produce a ball shape with no edges to drag (below).
Keep it Going
Work with the grain and overlap each pass at least 50 percent. Be careful not to stop the pillow on the surface or a mark will be left.
Smooth with the Grain
In the later stages of the application you should cut the surface back with 0000 steel wool after each additional coat.
After the final coat, apply wax and buff the surface to a smooth sheen. Although it’s not a super durable finish, it is smooth and begs to be touched. Perfect for lightly handled items.
Rub it in
Apply the oil and varnish mixture like you’re rubbing it into the surface. Finish with a few passes with the grain and let it dry thoroughly.
Looks, Feels and Performs Great
Like the shellac finish, apply some wax if you wish and buff the surface clean. This is also a surface that people will not be able to keep their hands off.
Equal parts double-boiled linseed oil, Tung oil, and semi-gloss urethane varnish give you the best of all worlds.
Shellac is a very “green” natural product that is safe to use. It is harvested in Asia, from secretions left on trees by the Kerria Iacca insect. People of Thailand, China and India harvest the resin by removing twigs and literally scraping off the larva casings and the lac resin they contain. This raw product is referred to as “sticklac”. Sticklac is refined by crushing the lac, and running it through a sieve to remove debris. The lac is washed and run through another sieve to further remove debris. It is then heated and stretched, either by hand or by machine, into thin sheets. It is then broken into shellac flakes. Continuous refinement of the shellac results in products ranging from a brownish orange to a nearly clear product called “super-blonde” shellac. The latter blonde shellac is fully de-waxed using solvents. Removal of the natural wax is important for adhesion, especially if the shellac is used as a seal coat beneath another finish.
Back in 1993, I learned how to mix shellac from flakes from James Krenov. Texts will tell you that to determine the strength of the shellac in solution you need to mix it in a known “cut”. A one-pound cut simply means that the mixture is equivalent to mixing one pound of shellac to one gallon of denatured alcohol. Jim had a much simpler method. You really don’t need a gallon of mixed shellac on hand because mixed shellac has a limited shelf life of about six months. What Jim would do is to place a handful of flakes into a jar, perhaps 3/4″ of flakes in a mason jar, and then he added enough alcohol to bring the level up to about three or four inches in height. Jim referred to the mixture as “shellac polish”. If you get the mixture too rich, you will know immediately because it will be sticky when you attempt your padding application. If you get the mixture too lean, then the build rate of the finish will suffer. It is common to apply six, seven or more coats of shellac polish. It has the consistency of apple juice when mixed, and the colour (using super-blonde flakes) of light apple juice. Keep in mind that it takes about 12 hours to melt the flakes fully in alcohol. If the flakes do not dissolve, the shellac flakes may have gone past their shelf life of about two years. Adding heat by placing the jar in a warm water bath speeds up the melting process. One of the wonderful things about using shellac polish is that it changes the colour of the wood very little. It would not be accurate to call this a resilient finish, because it can be damaged by water and destroyed by alcohol. It is, however, a very fine, natural finish with a feel that is hard to match. A wax top coat is highly recommended.
Shellac Polishing or Padding Technique
The good news is that you can apply your first three coats of shellac polish in the first hour! Owing to the fact that the shellac is mixed with alcohol, the solvent evaporates very quickly, leaving the dry shellac. Once the shellac finish begins to build, you have to leave a couple of hours between coats, and then four hours or more between coats when you get over six coats of polish. Each coat melts into the previous coat, so care must be taken not to apply a sopping wet pad onto the surface or the entire coating will be broken down.
Apply the shellac sparingly with a pad or “pillow”. Take a piece of clean white cotton about 12” square and fold in the corners towards the middle until you have a pillow. The rounded bottom of the pillow should be ball-shaped, with no edges to drag. Apply the wet shellac solution to the bottom of the pad and keep feeling it until it feels damp but not wet. Padding means wiping a thin layer onto the surface, but by no means should you ever see a swath of wet solution with a defined edge, similar to a paint brush stroke.
I refer to the application method as the airplane landing technique. Sweep in at a low angle of attack and land the pad on the surface about ⅓ of the way from the left edge of the wood panel. Pass the pad lightly across the entire surface and right off the right side of the board. Reverse the direction and now land ⅓ of the way from the right side of the board, then sweep across the surface and off the left side of the panel. Overlap each stroke by at least 50 percent. Feel the pad to ensure it is damp; you will have to re-charge it with a small amount of shellac every two minutes or so.
Lay down your first three coats and then cut back the surface using oil-free 0000 steel wool. Polish with a 6×3″ pad of steel wool between each successive coat of shellac. With moderate pressure, smooth the surface, with the grain direction, to flatten any raised grain and irregularities in the shellac.
After seven coats, cut the finish back with steel wool and then apply a thin coat of Clapham’s furniture wax. Create a scratch pattern in the wax finish with steel wool and then buff the surface to a beautiful sheen with a clean cotton rag. To repair the finish, rub with steel wool to remove the wax and then apply another coat of shellac.
Oil and Varnish Finish
A mixture of oil and varnish gives you the advantages of each component. The oil goes deep into the wood, popping the figure while giving a warm, rich look. The urethane varnish provides resilience to the finish. Mix equal parts of double-boiled linseed oil, Tung oil, and semi-gloss urethane varnish. The choice of semi-gloss is personal; I prefer a fine sheen to a bright shine. Use latex gloves since the double-boiled linseed oil and Tung oils usually have heavy metal drying agents added. Keep the used rags in a sealed container, since linseed oil may cause heating and auto-ignition!
Apply the mixture in circles with a white cotton pad, using moderate pressure as if you are rubbing the finish into the wood. Pad off the excess finish in the direction of the grain, using the same “airplane technique” as above. It is important to ensure that you keep the film thin – do not have any pooling of liquid remaining after you spread the finish. The surface will be blotchy due to varying absorption rates; do not try to correct this by adding finish. Allow the first coat to dry overnight.
Buff the surface with steel wool in long strokes, in the direction of the grain. Apply a second coat of finish and allow a full two days, or more, for it to dry. Ensure that the finish is completely dry! If you apply your next coat over a tacky coat, the previous coat may take months to dry and your finish will remain soft.
Cut the finish back with steel wool between coats, and then again after the third and final coat. The pores will remain open on some woods, so you have to consider that when deciding whether to use a wax top coat. I use this finish for everything from my workbench, to coffee tables. To repair the finish, simply steel wool or lightly sand the damaged area, and apply another coat of finish.