|French polishing is just one option for finishing a turning. Other possibilities include wax (in sticks or otherwise), oils (drying, non-drying, from your hands ...), friction polish, abrasive compounds ... and more.
Ask a turner to show you what he or she uses to finish on the lathe and almost anything is likely to "turn" up. That's not surprising. We typically choose a finish by first asking what it must endure, and most turned objects get little abuse. Bowls may get gently hand washed; spindles are typically vertical and suffer only airborne dust and grease, and art turnings suffer nothing beyond the caress of our hands. Consequently, almost any finish will do.
Let's take a look at some common finishes, arranged from the most minimal treatments to the most elegant high-gloss films.
Before we launch into the options, it is worth noting that sanding turnings is a bit different than furniture. Most lathe finishes are applied very thin, and the sanding scratches created on a spinning chunk of wood are usually cross grain. Hence, the scratches are far more visible. For that reason, it is wise to sand wood on the lathe much finer, often going to 600 grit or higher, depending on the wood. Harder woods require finer sanding. Thus, turning suppliers sell sandpaper with grit numbers well into the thousands. If you can see scratches, go finer - anything you see will be amplified by the finish.
Loading a stick abrasive onto a buffing wheel and using it to polish a turning, just as you would polish metal, is, in fact, a wax finish, since the compound in the stick is held together with a hard wax.
Nevertheless, this technique is a good and popular one, since it applies very hard wax while finely abrading the surface. The J. R. Beall Company (www.jrbeall.com) is one of several that offers a wide variety of bowl buffs, buffing wheels and stick compounds for creating this relatively foolproof finish, which can be done both on and off the lathe.
|Super glue can make a tricky, but fun, finish. Apply drops to the top of a slow-spinning piece as you move from end to end. The coat will dry in less than a minute.
|A chunk of walnut (top) and figured maple (bottom) give you an idea what some of the finishes you can use on turnings might look like.
Even without abrasive, wax is easy to apply and remove, almost foolproof, and requires little or no drying time. Once it's on and even, the piece can come off the lathe. Most waxes are also food-safe. Solid sticks of wax are available in different colors and degrees of hardness, from soft beeswax to hard carnauba. Harder wax sticks will buff to a higher shine, but they are all applied the same way. Press the wax onto the spinning wood until friction melts it onto the surface. Follow by pressing with a clean rag to spread the wax evenly and remove any excess, buffing it in the process. The same process works with paste wax, but because most contain solvents, you may have to let the wax dry for 10 minutes or so before you start in on the buffing.
While wax leaves wood looking clean and natural, oil adds depth and a small amount of color. Both drying oils (e.g., boiled linseed and tung oil), and non-drying oils (e.g., mineral oil), are valid choices. Drying oils cure either atop or in among the wood fibers, but non-drying oils stay wet indefinitely.
The easiest way to apply any oil is to flood it on, let it soak in for 10 minutes or so, then wipe off any excess. Some turners like to sand oil into the wood, creating a slurry of swarf and oil that helps fill tiny pores.
Oil is often used in combination with wax, resulting in a finish that applies with the ease of wax, but offers the enhanced definition of oil.
My favorite pen, turned from highly figured maple, sports a different sort of oil finish. I left it sanded, but unfinished. Over the years, it has become impregnated with sebaceous oil, the oil your skin exudes. Today, it boasts a rich satin sheen that gets renewed each time I handle it.
One of the most common terms you hear among turners is "friction polish." Like French polish, the term is used to mean both a material and a method of application. Almost anything you rub onto turning wood that creates friction, and subsequently heat, can justly be called friction polish. Thus, the ubiquitous HUT wax sticks (www.hutproducts.com
) are friction polishes, just as is any shellac-based French polish.
What confuses the issue is that several companies, like Mylands (www.myland.co.uk
) and Shellawax (www.ubeaut.com.au/shell.html
) sell mixtures specifically called "friction polish." Most are amalgams of common coatings laced with something that provides lubrication, so as to create an easier-to-apply film finish. How durable or glossy the finish is depends on what is mixed with what, and can run the gamut from something barely more than wax, to nothing less than shellac or lacquer.
Anything that cures to a film falls into this category, including shellac, lacquer, polyurethane and waterbased coatings. Most of these coatings require more drying time than wax and build up thicker than oils. They are a good choice when you need more protection or want a thicker finish, in any sheen from satin to high-gloss.
One turner I know, whose pieces are far too fragile for the pressure of friction application, uses aerosol cans of lacquer to get a high gloss finish. He drapes the lathe to protect it, then sprays lacquer onto the slowly spinning wood. Turning suppliers also carry dip finishes, usually lacquers, formulated to allow you to immerse small objects. Dip and hang the piece, letting the excess drip back into the can, and the thickly coated wood will dry fairly glossy.
Keep in mind that once any film finish is dry and cured, you can rub it either to satin or gloss just as you would any furniture finish. Use 0000 steel wool and paste wax to bring a film finish to smooth satin, or automotive rubbing compounds to buff lacquer, polyurethane, shellac or French polish to high gloss.
Applied with a cloth pad to the spinning wood, the shellac-based French polish lets you apply a built-up gloss film in just minutes. Technically, even pure shellac is considered French polish, but without additives, it takes some skill to apply it. Put it on too wet and it will form ridges, called "curdling." Press too hard, and you'll burn it right back off the wood.
Fortunately, some modified polishes, called "padding lacquers," add lubricating solvents or oils to the mix to make it handle more easily. Bull's Eye® French Polish (www.zinsser.com)contains no wax or oils: only pure shellac with a solvent lubricant that quickly evaporates as you apply it. The resulting film is pure shellac: a clear coating that makes wood look great and will not yellow with age.
Start by shutting off the lathe and sealing the sanded wood with thin, dewaxed shellac, or Zinsser SealCoat™. Flood it on liberally, and wipe off anything that does not absorb immediately. After 15 minutes, it should be dry enough to sand with fine 600-grit or finer paper. Turn the lathe on slow speed, charge a cotton or linen cloth pad with a modest amount of French Polish, and gently wipe on a thin coat of finish, coating the whole surface evenly. In a minute or two it will be dry enough to pad on another thin coat, and you may continue to build up coats until the surface looks the way you want it. If you get impatient and mess it up by going too fast, let it dry, sand it smooth, and continue with more thin coats.
"Something Completely Different …"
Want something unusual? There are two highly durable finishes based on cyanoacrylate (super glue) that are appropriate for small turned objects. Though difficult to control, cyanoacrylate glue yields a thin, shiny, extremely tough finish rather quickly. Use folded paper towels, since the glue will dry on the applicator, and plan on a new one for each coat.
Run the lathe on slow speed, place the towel beneath the pen, and add drops of cyanoacrylate to the top as you move from end to end. Get one coat on evenly and let it harden, which takes less than a minute. Use a new towel for each coat, and sand irregularities between coats. Wear protective eye gear, and be sure to have debonder on hand: odds are, you will glue at least two fingers together if you do this without gloves.
The other finish, taught to me by the late Steve Blenk, combines cyanoacrylate with boiled linseed oil. Apply a coat of boiled linseed oil, then immediately apply a coat of cyanoacrylate. As soon as the two come in contact, the glue causes the boiled linseed oil to cure into a hard solid. Again, add as many coats as you like, but practice this on scrap first. This reaction goes fast, and quickly builds a very beautiful and durable gloss film.
This is tricky, but fun, and unusual enough to wow the crowd at your next local woodworker's guild meeting.