Shellac is an animal product, a resin secreted from the Coccus lacca (lac beetle), a scale that feeds on certain trees in India and southern Asia.

After hatching, the nifty little bug snoops around for a place to eat, selecting a stem or leaf as its breakfast counter. It has a sharp teensy beak, and it uses that to puncture the tissue of the plant, and settle in for a lifetime of sucking nourishment.

After feeding, the insect secretes a resin, which dries and hardens into a protective covering called lac. The lac is collected, crushed, washed, and dried. After cleaning and heating, it is drawn into thin sheets of finished shellac.
The level of refinement, the timing of harvest, and source of the lac, determine the specification color that comes to you, the happy woodworker.

The largest uses for shellac are for the food, drug, and cosmetics industries. Fruits and vegetables in the produce aisle of your favorite grocery store are coated with shellac and wax to make them shiny and eye-catching. In the world of cosmetics, women (and men) use shellac-based hair-spray to make themselves appear shiny and more eye-catching. Many vitamins, pills and food supplements are coated with shellac to make them slide easily down your throat, into your tummy. Of course the most important use of shellac, in my not-so-humble opinion is as a woodworking finish, where you can make your projects shiny and eye-catching.

Here are a few of the ways shellac can make you a happier wood finisher.

• Use a spit coat (1/2# cut) of dewaxed shellac as a barrier coat between other stains/finishes. This is especially useful when refinishing, and you're unsure what's on the wood, and you're unable to strip it all off. Shellac will stick to anything but wax.
• Wood conditioner - a spit coat of shellac can be used to avoid uneven absorption of stains (stay tuned, and you'll see how to avoid staining in the first place).
• Sealer - shellac can be used to seal the ends of wet timbers, to help regulate moisture loss while drying, and reduce cracking, splitting and warpage. Also, when working woods with a high tannin content, a spit coat of shellac will prevent you from marring your workpiece with black and blue fingerprints.
• Top Coat - There is no more beautiful finish for woodwork, than French polish.
  Please check these two great sites.
  • Check this amazing write-up on french polishing, courtesy of Milburn Guitars -- Updated & Illustrated
     
  • Shellac & French Polish by Pete Taran
     
• Seals smells too! No musty smell on old furniture.
  A spit coat takes care of it.

Other Features of Shellac

• All shellacs imbue some bit of color to wood. They also won't yellow as much with age as other varnishes and lacquer (though it does change subtley with exposure to light)
• Barrier coat - prevents stains and finishes with same base, i.e., oil-based stain and oil-based varnish, from bleeding (ghosting) into one another. Works similarly with lacquer stains/varnishes. Also a good barrier between incompatible finishes.
• Stops pine pitch from bleeding
• Dries hard, and won't gum-up like oil finishes (perfect for bookcase shelves).
• Easily repairable (new finish melts into previous layer)
• Outstanding clarity, really pops the grain of those wild grained woods
• Tintable - avoid uneven staining by tinting your projects using colored shellac. Gives complete control over how much to tint your project. You can use a nearly infinite combination of the various shellacs to color your project, for example garnet over a seedlac washcoat, then French polish with blonde.
• Dries quickly. Avoid the problems inherent with varnish (dust specks, bubbles). You can recoat thin coats (recommended) in usually less than two hours.
• Problems are easy to fix - level your finish with a hand-held scraper, simply slice off runs or sags with a razor, blushing (water vapor trapped in the finish) fixed by wiping down the finish with 1/4# cut shellac-soaked rag.
• Non-toxic when dry. Shellac is a USP-approved food coating. This doesn't mean you should grab a handful of flakes and eat it! I'm not selling food here, I'm selling wood finishing supplies.
• Easy on your tools. Forgot to clean your brush? No problem. Fully-dried shellac will dissolve in alcohol or water/alkalai solution.
• It makes sanding and planing difficult woods easier. A spit coat stiffens the wood fibers, allowing the cutting edge to shear the wood cleanly.
• If you're stripping porous wood, and the stubborn pores still have gunk in them, you can apply shellac, then strip it again and the shellac will pull the gunk out!
• Got a greasy spot on the wall of your house? Dab a little shellac on it, and come back and paint it two minutes later; the grease won't bleed through!

The following books are excellent references on using shellac, and wood finishing in general.

• • Classic Finishing Techniques
    (Excellent - A Must Have)
    Sorry -SOLD OUT -- Out of print - CHECK LIBRARYt
    Sam Allen / Sterling Publications / ISBN: 0806905131
     
  • Great Wood Finishes:
    A Step-By-Step Guide to Consistent and Beautiful Results
    Jeff Jewitt / pub. Feb. 2000, Taunton Pr; ISBN: 1561582883
     
  • Understanding Wood Finishing:
    How to Select and Apply the Right Finish
    Bob Flexner, Paperback, 320 pages, ISBN: 0-87596-586-0
     
  • New Wood Finishing Book:
    Michael Dresdner / Paperback / Pub.
    1999 Taunton Pr / ISBN: 1561582999
     
  • Hand-Applied Finishes:
    Jeff Jewitt / Taunton Pr / ISBN: 1561581542