Finishing - Searching for Good Shellac

Dinabandhu Mitra, a Kolkata-based DIY enthusiast, has been helping me search for top grade Shellac. The search for Shellac must begin in Kolkata because that is the global centre for Shellac production and sales. The business is entirely dominated by traditional Marwari families who have been in this business for generations. Raw Shellac is procured from the forest areas of eastern India and is refined in small factories in and around the city.

There are numerous grades and varieties of Shellac, the best being the ones that have been processed to remove impurities and the wax present in natural Shellac. This "de-waxed" Shellac is the most sought after as it is easy to dissolve, apply and bring to a high polish. The removal of wax also dramatically increases the adhesive quality of Shellac and this allows it to be used as a sealer on various kinds of wood, particularly the oily ones that resist most finishes.

De-waxed Shellac is also widely used in the pharmaceutical industry for coating medicinal capsules and in the food industry for various kinds of coatings including on chocolates. Shellac is food safe and is an organic, non-toxic material.

Indians have been using it for thousands of years to polish furniture and other objects. The West discovered Shellac only in the 18th century and was completely sold on it as a finish until the advent of durable chemical finishes such as nitro-cellulose lacquer and polyurethanes.

Dinabandhu, who has moved to Kolkata from Bangalore recently, has been scouring the city to locate various kinds of suppliers for his woodworking hobby. He was kind enough to assist me and others locate good and reliable sources for Shellac.

Fortunately, he appears to have stumbled upon a few promising suppliers and managed to get samples from them, which he sent to me for testing.

The varieties he sent were Blond, Super Blond and Platina, the last being the most reputed variety.

All three varieties are de-waxed and de-colourised. These varieties of Shellac are produced by dissolving raw Shellac in a solvent (usually alcohol), bleaching it with activated carbon and then re-extracting it by boiling away the alcohol. The Shellac thus obtained is rolled and crushed to produce flakes.

Blond

Super Blond

Platina

Dinabandhu procured three samples of the best types and from first appearance all three looked good, although they had solidified into a crystalline mass and were no longer in the form of flakes. This could be because of any of several reasons: they were not properly refrigerated, or they were old or they congealed during transit.

I later discovered that the flakes had been supplied as flakes but had hardened as they were not refrigerated for several days after they arrived. Ideally fresh de-waxed Shellac should be in flake form but I found that the crystallised version to be quite usable as it can easily be broken into smaller pieces with a mallet.

I could not make out any significant difference in colour between the Blond and Super Blond varieties but the Platina was definitely lighter. De-waxed Shellac, I am told, comes in various colours starting from dark brown to garnet and light yellow. The colour largely depends on the degree it has been de-colourised.

Platina is the lightest
I them put all three samples in small jars with spirit (the kind stores sell if you tell them it is for laac dana). They dissolved easily overnight and the colour difference was obvious, the Platina variety being the lightest.

I applied all three samples of dissolved Shellac on wood and found they dried almost instantly, suggesting the quality of the samples were good.

Apparently, old Shellac will take very long to dry and in some cases will not dry properly. This is one reason why users are advised to buy fresh Shellac and dissolve it in spirit only a few days before use.

Dinabandhu has stumbled on to some good sources and I would advise him to start a small side business supplying Shellac at reasonable rates to woodworkers in India and abroad, especially those who cannot or do not need to buy in bulk (25 kgs to a tonne!). Although although he is extremely reluctant to make this a business, should he do so at any time in the future it would be a great help as sourcing reliable supplies of most materials and tools in India is a big problem.

Indranil Banerjie
15 July 2014

Comments

  1. Great to read this article. Could you update us on what are the approximate prices for the different grades of shellac?

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  2. Its about Rs 1350 per kg for bulk purchases. But variable I think depending on supplies and how much you buy.

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  3. I will be in Kolkata within a month and would start few new projects. Will be great to know where I can get some of the shellac supply there. Can somebody help?

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    Replies
    1. Get in touch with Dinabandhu Mitra email: dinu.mitra@gmail.com

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