Benefits of Shellac
Shellac is a beneficial finish to stock in your shop and mixing fresh shellac from flakes is easy. I like shellac because the application is fast, and you don’t need a spray booth unless you choose to spray it. The tools to apply shellac are varied and simple. It dries relatively quickly, and it repairs easily, and being able to mix fresh shellac from flakes on-demand has many advantages. Finally, the gloss finish you can achieve is as reflective as a still lake mirroring a mountain scene!
I mix fresh shellac for many reasons. First, liquid shellac has a shelf life of about one year, depending on the storage environment. Mixing fresh shellac yourself gives total control over the freshness of the product. With commercial shellac mixes, you are unsure of its processing date. Old shellac does not cure entirely and can remain gummy after the solvent evaporates. Canned shellac may also have additional chemicals added to extend the shelf life. Such chemicals could negatively affect your finishing results.
Second, you get to pick the type of solvent or alcohol in your mix. I choose to work with isopropyl alcohol….a friendlier alcohol. Commercial mixes use more toxic varieties like ethanol.
Third, you can mix any pound cut or viscosity of your choosing from flakes. That’s not so easy with commercial liquid shellac if you need to increase the thickness. A heavier pound cut of shellac is ideal to use as a barrier coat to prepare metal-inlay.
Shellac has a Varied History of Uses
Shellac itself is non-toxic and used throughout many industries, including cosmetics, food, and drug. You can find its use in hairspray and workable fixative. Commercial orchards spray shellac on apples and other fruits to seal in moisture and make them look more appealing. Shellac even coats candies like candy corn, Hershey’s Whoppers, Milk Duds, Nestlé’s Raisinets, Goobers, Tootsie Rolls, Sugar Babies, and more.
The use of shellac is common in the pharmaceutical industry. While sugar is the primary top-coat on coated tablets, the sealer is a coat of shellac designed to protect the core. The shellac coating hardens the surface to protect the core (which can be very fragile) in subsequent process steps of manufacturing.
And of course, you can also find shellac in the paint industry. A product like Kilz can seal knots in wood-trim to prevent sap from bleeding through and staining opaque paints. It’s also used as a sealer over water stains to repair drywall after a roof or plumbing leak.
Shellac has an established history, so I’m comfortable and confident in using it. I use shellac primarily as a sealer, but I also French polish with it on occasion. I devote a complete chapter on this very subject in my DVD, Brilliant Finishes for Woodturners. Because shellac is a natural product, it carries with it a non-toxic and food-safe status.
What is shellac?
Shellac is a resin secreted by the female lac bug (Kerria lacca) on trees found in India and Thailand. The lac is a protective shell in which the female can lay her eggs. It’s processed and sold as dry flakes or buttons.
There’s a multitude of colors and grades of shellac flakes and buttons available. Color is influenced by the type of tree sap the bug is consuming. Seedlac is the least processed shellac. It is derived from raw seedlac resin from which all other shellacs are made.
Button lac contains wax, and for that reason, I don’t recommend using it unless it’s the only finish you might apply. It’s porous, and other finishes will not adhere to it, so I don’t use it in my shop. The selection of dewaxed flakes available includes platinum blonde, super blonde, blonde, orange amber, ruby, garnet, and orange shellac. Orange shellac, historically quite popular, was used as a combination stain and finish.
The lighter tints include blond, super blonde, and platinum. Platinum is my favorite tint and the one I always stock in my shop. Platinum imparts a slight golden hue over any surface and gives the various shades of color found in wood a cohesiveness…..much like the great masters who placed tinted washes over finished paintings to bring unity to their colors.
Here is a List of Shellac Mixing Supplies:
- Shellac Flakes (preferably Platina or Platinum)
- 99.9% anhydrous isopropyl alcohol
- Rotary tumbler
- 13 oz. mixing jar (pickle jar with rubber seal in the cap)
- Storage bottles
- Masking Tape
- Measuring cup
- Sheer curtain or cotton t-shirt material (filter)
- Old T-shirt
Solvents for Shellac
To dissolve shellac, I like to use anhydrous (or water-free) isopropyl alcohol as the solvent. It might take a bit longer to dissolve the shellac, but the advantages outweigh this slight inconvenience. It smells better, it isn’t toxic, it has no chemical additives, and it’s relatively easy to find online (outside of a pandemic!). In a pinch, you can obtain some Everclear (190-proof) at your local liquor store…i.e., if it’s legal.
Avoid using rubbing alcohol from the local big box stores; it can contain up to 50% water. You don’t want water in your shellac. I also avoid denatured alcohol, as it has an unpleasant odor and contains toxins (denaturants). Also, it’s getting more challenging to obtain 190 proof denatured alcohol from the big box stores. Read the SDS sheets to understand the chemical makeup because impurities in shellac may cause finishing problems.
Now, select the grade of flake you’d like to mix. For mixing the platinum shellac, a rotary tumbler is ideal. Used in the polishing of stones, you won’t be needing the canister part of the tumbler. So in its place, use a 13 oz pickle jar. Just make sure the jar you choose has a good rubber seal on the inside of the cap.
Mixing Fresh Shellac – The Easy Way
For your first mix, try a 2 lb cut of shellac. Pound cut is the measuring unit of shellac flakes dissolved in a gallon of alcohol. It’s the viscosity or thickness of liquid shellac, so a 2-pound cut refers to 2 pounds of shellac flakes or buttons dissolved in a gallon of alcohol. This cut is perfect for French polishing, or you can cut it down by adding more alcohol later and use it as a sealer. Dissolved shellac has approximately a shelf life of one year in my environment, so a gallon of shellac is a lot more than I can use in one year. So when I mix, I use the same ratio, but less volume.
Use the Alcohol : Shellac Ratio Table Below
|99.9% Alcohol||1# Cut||1.5# Cut||2# Cut||3#Cut|
|128 fl oz.||16 oz flakes||24 oz flakes||32 oz flakes||48 oz flakes|
|64 fl oz.||8 oz flakes||12 oz flakes||16 oz flakes||24 oz flakes|
|32 fl oz.||4 oz flakes||6 oz flakes||8 oz flakes||12 oz flakes|
|16 fl oz.||2 oz flakes||3 oz flakes||4 oz flakes||6 oz flakes|
|8 fl oz.||1 oz flakes||1.5 oz flakes||2 oz flakes||3 oz flakes|
Weigh out approximately 2 oz. of shellac flakes on a scale that’s accurate to at least a tenth of an ounce. In the center of an old T-shirt, spill out the measured shellac flakes. The commercial flakes are much too large for processing, so it helpful to pulverize them with a mallet. Fold the t-shirt over the shellac to keep it contained in the cloth while moderately pounding the flakes. These smaller flakes will dissolve much faster. Place the flakes into the mixing jar, and to that, add 8 oz. of isopropyl alcohol. Seal the jar well. Make sure it doesn’t leak. Then run masking tape around the lid of the jar as extra insurance against leakage.
Place the jar into the rotary tumbler and turn it on. The slow-rolling of the tumbler will completely liquefy the shellac in about eight hours. This process is a much faster way of making shellac on-demand than agitating it by hand over a three day period.
Keep track of the date you mix your shellac by dating the storage bottles and labeling the pound-cut. You’ll need to strain the shellac, and for this, it’s best to use a piece of sheer curtain material. (Use cotton t-shirt material in a pinch. It’s a slower strain.) The liquid shellac flows freely through sheer curtain material and strains all its impurities, like twigs, bug parts, and un-dissolved shellac. This nets about ten fluid ozs. of liquid shellac that’s a two-pound cut, perfect for French polishing.
Now, to make a shellac sealer, take one fluid oz. of two-pound cut liquid shellac and add three fluid ozs. of alcohol to make a quarter-pound cut. This viscosity is excellent for sealing all types of wood before applying a friction finish like Crystal Coat. I also use this sealer for the inside of all my peppermills. Shellac sealer helps protect the peppercorns from absorbing any flavor or aroma from the different wood species I like to turn.
When you think of shellac, it brings to mind the finish on old antique furniture with a warm and inviting tone. It certainly has impacted finishing and finishes in the past, but it’s still here in the present, and I foresee it being well-rooted into our future.
I think you’ll find that mixing fresh shellac from flakes is relatively easy. You’ll continue to find new uses around the shop, and it will pay big dividends because you will always have fresh shellac in the viscosity you want when you need it.
Please post a comment down below and let me know how you use shellac. It would be interesting to hear how others use this versatile finish.