January 17, 2010
Welcome to Issue #09 of
Wood Shop News
brought to you by:
wooden box maker.com
In this issue:
Working with shellac
I've been using shellac recently so I thought I'd write about it in this issue. Here's a link to an article about using shellac, including a chart for mixing different cuts.
This issue's "personal note" describes the process of making - or should I say harvesting - shellac. Even if you don't use shellac it's an interesting story.
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(Located S/SW of Boston)
Learn new skills or hone old ones in small group sessions tailored to the individual.
Classes are limited to 3 people and take place in my shop outside Boston. They generally meet once a week for 2-3 hours. The sessions go on as long as students are interested, a few months or a few years.
As students progress, class becomes "open shop" time when they work on the projects of their choice while I answer questions and give suggestions as things come up.
Individual instruction is also available.
Click on the links below or contact me
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New & For Sale
Visit my sale page for new work and sale items.
Or visit wooden box maker recommends for ideas on books and tools (category list top right of page).
In Progress
This past holiday season was a busy one. I had the usual last minute custom orders as well as a couple shows. I also had an unusual custom order.
I was commissioned to make a presentation box for Oprah Winfrey. Needless to say, I was excited about the project and the recipient!
The story behind the box is that a candle company put one of their custom candles into a high quality vase and the box was to keep the vase safe. I spoke with the owner of the candle company several times, working out the design details. Then I made the box shown. To the right is the open box with the candle, below is the box closed.
The box base is lined with silk. The inside of the lid has velvet on the sides to protect the box and also so the lid slides on slowly and easily. The trick of the project was to get everything to fit properly. Since the velvet changed the dimensions slightly I had to make the size exactly right. I made a prototype of the box from narrow material and added the velvet, then I took the measurements directly from the prototype.
I put on 5-6 coats of high gloss paint, until I could see myself in the surface. Then I put on one more.
Apparently it was a success. They asked for two more.
On a Personal Note
Shellac is made from the resinous secretion of microscopic bugs collectively known as lac bugs. For those with a scientific bent, lac bugs are from the coccoidea family and include Laccifer lacca, Carteria lacca and Tachardia lacca.
The process of making shellac starts with these microscopic creatures. It begins when huge numbers of lac bugs colonize branches of host trees. (It takes about 100,000 lac bugs to make 500 g of shellac flakes).
Many trees host lac bugs, especially in India and Thailand. Those trees include members of the soapberry, pea, buckthorn and mulberry families .
The lac bugs feed on the tree, sucking sap into their proboscis and then secreting the resinous lac. The males fertilize the females and then fly away.
The females never develop wings. Instead they lay around 1000 eggs and continue eating and secreting lac until they die. During this process the lac builds up on the branches, ultimately covering the female bugs and the eggs. (Click for photo)
The lac protects the eggs from predators, except, unfortunately for the lac bug, it also attracts humans. Once the branches are thick with resin the branches are harvested as sticklac.
Sticklac refers to the entire branch that is coated with the resin of the lac bug. Workers cut the resin coated branches for processing into shellac.
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| sticklac before processing |
The sticklac is crushed and sifted to remove dirt and crushed bug parts. It is then washed to further remove impurities. From this point the lac is called seedlac.
The color of the lac dissolves in water and can be removed and used as dye or left in the seedlac to give color to the final product. The color and quality of the lac comes from the type of host tree as well as the species of lac bug.
After repeated washings the seedlac is laid out to dry. 
To turn the seedlac into shellac it is treated with either heat or solvent. Traditionally the lac is heated in cloth tubes. As it melts the cloth acts as a sieve, further cleaning and purifying the lac as it passes through the fabric.
The resulting shellac is then stretched into thin sheets while still warm. Hot lac is scraped from the cloth and dropped onto a hard surface to make button lac.
When made by hand a worker molds the sheet by hand and then stands in front of a fire while the shellac dries.
The dried sheet is then broken into small pieces. The same process can also be done using steam and hydraulic presses.
The heating process keeps the wax in the shellac. To make de-waxed shellac such as that used by woodworkers, the lac is dissolved in a solution (usually industrial alcohol) and then filtered. The alcohol is evaporated and recovered and the shellac is pressed into sheets and then broken into small pieces. This process allows the manufacturer to control the amount of wax in the shellac.
The wax itself can be reclaimed from the process and used for polishing.
Shellac can also be bleached or further refined into aleuritic acid which is used in the perfume industry.
A short list of other uses for shellac includes:
binder for matches and ammunitions binder for cosmetics (hairspray, shampoo) coating for spark plugs hat stiffening agent (leather and felt) primer for plastic binder for India ink
and of course you probably had some shellac with your breakfast, since it is used as a coating for coffee beans, as well as on candy, processed food and pharmaceuticals.
If you are using shellac as a finish, however, don’t drink it. It is dissolved in denatured alcohol. Once dried it is again non-toxic.
Sites used for this article include: a full description of the lac bug and the process of collecting lac
interesting pictures of process of making shellac including those above if not otherwise noted
for information on some of the uses of shellac
company that sells shellac has some history and other info
information on shellac bangles
drawing of lac bugs used above
photo of branch with lac bugs covered with resin
scientific info about lac bugs and host trees
Final Words and Errata
I hope you have enjoyed reading this ‘zine. Do you have ideas for future topics? Comments? Feedback? I'd love to hear from you. Just hit reply and tell me what you think.
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Kate Taylor Creative Woodworking