This is Art Baby

April 2011

Wow, great response to the pen press plans. I can't wait to see some finished projects.

I am frequently asked about the finishes I use. Since many of the videos on my website show the use of shellac, I want to share with you how I use shellac on a turning.

OK, so what is this stuff anyway?
It is a product that dates back over 3000 years, and has been used to make record albums, molds for castings, and even false teeth. It's an organic plastic created by the lac bug "Coccus lacca." Sometimes called the lac beetle, it is actually a scale. What is a scale?
Apparently, it is a bug that looks like a beetle...

The Lac bug burrows its head into the sap wood of trees in India and Thailand and stays there for life. While feeding, the Lac bug secretes a polymer that eventually covers  it's body. Europeans discovered spindle turners in India holding pieces of this waxy, cocoon against the spinning wood to create a high gloss finish. The process has since been improved by melting the polymer with heat and filtering out the bark and bug parts, then dried in a flat sheet, and later broken into flakes.

The shellac flakes dissolve in ethanol alcohol. In the United States, the alcohol most widely used is denatured alcohol. This is ethanol alcohol that has chemicals added that make you violently ill if you drink it. Since it's nature is an intoxicant, by making it undrinkable, it is spared the taxes and regulations associated with alcoholic beverages and keeps the price low.  The ratio of shellac flakes to alcohol is defined in the unit of 1 pound cut. Meaning the ratio in pounds of shellac flakes to one gallon of alcohol.

Premixed shellac is usually sold in 3 pound cut. Thinner cuts can be used as a sealer under other finishes. Shellac works well as an under coat and stain sealer for most finishes as long as you use shellac that is dewaxed. Natural Shellac can be 3% to 5% wax. When I mix my own shellac I use about a 2.5 pound cut. Fresh shellac is very easy to apply and has a shelf life of about 6 months. When shellac is too old it will take a very long time to cure, if it cures at all. You can test your shellac by placing a couple drops onto a hard surface to see if is hardens quickly or stays as a rubbery uncured drop. Once cured, shellac is a hard food safe finish.

Shellac is self thinning, meaning when you apply each coat, the cured layer below will dissolve and create a new polymer bond with the fresh layer. This effectively creates one thicker layer. It is not necessary to sand between coats as you would for polyurethane. Your decision to sand is based solely on whether or not you need to remove a run or trapped dust. The use of several thin coats does create a harder finish than one thick coat. Since it is not layered like polyurethane, you can easily repair a small area including sanding through to the wood and reapplying several coats of shellac leaving no evidence of the repair.

I love to use shellac on segmented turnings that are intended as art and not used and handled frequently. This finish will last for years. Only requiring an occasional dusting.

Let's Get Started...

I sand the turning to 400 grit and wipe with a clean rag and use high pressure air to remove all dust. This is especially important in a segmented piece where dust may stain adjacent colors. Avoiding paduk will make your life a lot easier. I like to do most of my finishing on the lathe. The first coat is applied with a paper towel with the lathe off. Move quickly keeping the towel wet. The shellac will become tacky quickly, so don't go back over areas you have already coated. A French polish is the technique of applying shellac combined with 100% pure olive oil. This makes it easier to go over areas with pressure and avoid lift off from the shellac becoming tacky. The oil will rise to the surface as the shellac cures, then after the final coat simply wipe to remove the oil. This isn't nessasary for a turning, but something to think about...

The shellac dries quickly. I can usually re-coat once every half hour. I apply the remaining coats with the lathe running at slow speed.  I will sand as needed, maybe after each 3 or 4 coats. Use your hands to “see” how smooth the surface is when determining when to sand.

After the last coat has dried for a few hours, ( 8 or more coats ) I will reverse chuck the piece, finish turn the bottom, sign it, then repeat the shellac process on the bottom, blending into the cured finish.

The next step takes your nice finish to a fantastic finish.
I learned this technique when I needed to remove some shellac that was too old and was not curing. When you sand shellac that is not thoroughly cured, it balls up on the sand paper and clogs it and generally makes a mess of the finish. The use of a lubricant makes the sanding easy and the sand paper last for a long time. Water works as a lubricant, but I use a lot of maple and water raises the grain on maple and creates more work. I like to use mineral spirits. Get your self a good set of rubber gloves. Soak a folded paper towel with mineral spirits. Wipe the area that you are going to sand, then blot the sand paper on the folded towel and start sanding. I start with 400 or 600 grit, sanding lightly and re-wiping with the wet paper towel frequently to keep it wet and to remove the white slurry that is created. Again, use your fingers to “see” the smoothness of the finish and sand the entire turning. I repeat this for 1000 grit then jump to micro-mesh. Usually 500, 1000, 2000, 4000. By this time you are starting to recover the shine that was sanded off. You can continue to even finer grits but at this time I usually move to the buffing wheel.

Have fun, learn new things, be safe,
Larry Marley
Buff it, Buff it good...
I like the Beal Buff system that uses three wheels. The first wheel is made of linen and is lightly coated with tripoli. It is important to hold the turning below the center line of the wheel to avoid the wheel grabbing the turning and throwing it to the ground. I read about this, then had a turning pulled out of my hand and thrown to the floor, and now I am a believer. Move quickly over the surface to avoid heating up the surface, as this can soften the fresh shellac and wear a hole through the finish. The second wheel is a 50/50 blend of linen and flannel with a light coat of white diamond compound. This is a finer abrasive and helps remove the tripoli. Some people skip this step on dark woods to avoid white specks in the grain. If you do see white specks, use a soft paint brush soaked in mineral spirits,and rub the area in a circular motion, and wipe with a paper towel. This will work to suspend the white specks into the mineral spirits so you can wick them into the paper towel. The final wheel is made of flannel and is lightly coated with carnauba wax. This puts the finishing touch on the turning.
The result is a hard, high gloss finish.
Shellac is harder and more scratch resistant than many lacquers, is UV resistant and will not darken with age.  Colors vary from the type of tree. Common colors are blonde, orange, and garnet. I have used this for competition pieces, and have had judges comment on my nice lacquer finish.
I ate food that came out of a bug?
If you have eaten raisenets, you've eaten shellac. The largest consumer of shellac is the pharmaceutical industry, where it is used to coat pills. Let's be clear here. By food safe I mean safe to eat. I don't recommend it for pieces used to prepare or serve food because it will not hold up. Since it dissolves in alcohol, it is best to avoid using it on items like bottle stoppers that are used around alcohol. Many friction polishes are based on shellac.