Easy Shellac Finish

W

hen I first began woodworking a few years ago, what confused me the most was the huge variety of finishes available, starting from French Polish to Polyurethane, varnish and what have you. It was a bewildering range and I did not quite know where to start. Rather than doing a lot of research, I simplified matters by visiting my local paint shop to find out what was available and what was not. Fortunately I chanced upon a fairly well stocked paint shop in Noida which employed a helpful sales boy, who happened to be a Bengali from Calcutta. As I asked questions, he chattered away helpfully in Bengali and carefully explained a few basics.

I learnt that almost 90 per cent of the finish used in India is shellac based. Shellac or laakdana comes from the sticky secretion of a tiny insect (called Lacifer Iacca) and is harvested from forests in eastern India and Thailand. These secretions are collected and processed into usable shellac of which there are various kinds (see photo below). The types are differentiated by their wax content and colour. I prefer the de-waxed type because I can use it both for sealing the wood as well as for the polishing part. But the waxy type produces a better polish.

A wide variety of shellac is available. These  include the following:
Seed Lac; warm neutral brown
Kusmi Seed Lac; lighter carmel tones
Kusmi Buttons; small carmel 'buttons'
Button Lac; golden light brownish amber
Garnet Lac; deep rich brown
Dewaxed Garnet; brown-red
Dewaxed Orange Lac; Deep rich color
Lemon/Orange; light lemon to orange color
Almost Blonde Dewaxed; pale beige/golden tone
Blonde Dewaxed; light pale
Super Blonde; very light clear
Platina; extremely clear.

Shellac is a most amazing substance and the best part is that it is completely safe for humans - although beware that the spirit in which it is dissolved could be poisonous. Shellac is extensively used in the pharmaceutical and food industries. The shiny coatings on Gems and similar chocolates is Shellac and so are the coatings on a variety of medicinal tablets and capsules. Furniture and other wooden objects finished with Shellac are therefore child safe.

One word of caution, be careful about what you buy for prices of shellac in India have gone through the roof, apparently because of successive years of crop failure. The lower end orange Lakdaana is selling for almost Rs 900 per kg in Delhi. The de-waxed variety costs between Rs 2,000 and Rs 3,000 per kg. The super blond and platina varieties are the most expensive. A lot of mixed stuff is being sold in the market. One way to be sure that you have bought the right thing is to take it home and test it. Genuine de-waxed varieities should leave no sludge at the bottom after it has dissolved in spirit.

A few varieties of shellac – the middle one is the waxy variety

Preparing Shellac

Let me explain the process simply. This is done by dissolving the shellac flakes or pieces in spirit. Traditionally, shellac was dissolved in ethanol but nowadays ethanol sales in India are strictly controlled and few shops sell it. They sell some kind of spirit which is probably rectified spirit or something similar. It doesn’t matter – what does is that the shellac needs to dissolve in the spirit, which must evaporate easily to leave a fine film of shellac over the wood. The more shellac that is added to a jar of spirit, the more concentrated the mixture will be. Use a concentrated mixture for sealing wood and a lighter one for polishing.

It takes about a day or so for the shellac to dissolve fully and after that carefully pour off the clear part, leaving the waxy sludge at the bottom of the jar. This shellac is now ready to be used. By the way, if you are going to do a lot of this, don’t throw away old jam jars and the like. They make excellent containers for preparing shellac. Also, try to use freshly dissolved shellac whenever possible. For, dissolved shellac starts changing chemically and becomes unusable in a few months - after six months it becomes tacky and does not dry properly. Also, I am told that Shellac flakes, powder etc. are best stored in the fridge to prevent deterioration.

Dissolved Shellac - yellow on the left and orange on right. Note the waxy sludge in the last bottle.

De-waxed Shellac. This is an amber variety that has not been bleached. Once bleached, de-waxed shellac is termed "Blond" or "Super Blond" according to the lightness of the colour. This quality of Shellac is not readily available in local paint stores in India. It is more than double the cost of Laakdana.

De-waxed Shellac dissolved in rectified spirit. This shellac produced this warm amber polish which looked fabulous. The other interesting point is that the de-waxed shellac left no sludge at the bottom at all, proving that I had got hold of some quality stuff.

Surface Preparation

The surface of the wood to be finished needs to be sanded as per your preferences. In most cases, rough sanding is good enough but if you want a mirror finish, then spend some time sanding the wood surface using a range of sandpaper starting from about 120, 180, 240 and ending at 320 grit. Before doing this make sure you have plugged all holes and fixed dents and other imperfections on the surface. Do not skip the stages in the sanding process as you will end up spending more time and achieving a poorer result. Using a random orbital sander speeds up the process but sanding by hand is as good. Rough sanding only requires two rubs: first with 120 grit and then with 180 grit. I usually do not sand pieces like windows, shutters and the like for a mirror finish but take time with interior pieces.

Orange Shellac (Laakdana) - my favourite

Sealing the wood

All wood has pores, grain and so on which usually need to be filled. This is a two stage process. First stain the wood with your choice of colour and then brush on a generous coat of concentrated shellac. I prefer the laakdana type with its warm amber tones for most job. When this first shellac coat has dried, apply a mix of chalk power and shellac diluted with a little spirit over the surface, making sure that the excess is scraped off. Once this pore filler dries, sand it with 320 grit paper. Now the pores should be filled and the surface should feel smoother. The rest of the shellac coats go over this.

Applying the Polish

The subsequent coats of shellac should be applied with thinner cuts of shellac. I find it easier to brush on thin coats with a regular paint brush and sand each layer with 320 and 400 grit papers. While sanding it is of utmost importance to ensure that no brush marks, streaks, bubbles or other imperfections remain. Apply as many layers of shellac and keep sanding until you get the sheen desired. The traditional way of French Polishing is with rubbing in the shellac with a wad of cotton wrapped around another pieces of cotton (called the rubber) but this takes some practice.

Rubbing the Finish

Shellac layers applied with careful sanding in between produce a high glossy surface which is good enough in most cases. But if you want a real mirror finish you will want to rub the final layer with some sort of rubbing compound. Traditionally, French Polishers used fine abrasives such as crushed pumice or rottenstone. Nowadays companies like 3M produce excellent synthetic compounds for finishing. I use these synthetic rubbing compounds which are of the consistency of shoe cream. This compound needs to be spread over and rubbed until it dries and begins to produce a high gloss. Buffed with a lambswool bonnet, the results can be amazing. You should be able to see the reflection of your finger on the surface. Some people use a final layer of wax  but I avoid it - wax is always a problem when one wants to redo the polish.

For more information read these two excellent articles available on the Internet:

Tips for Using Shellac By Mitch Kohanek [http://americanwoodworker.com/blogs/shop/archive/2009/07/02/shellac.aspx]

And

SHELLAC – A TRADITIONAL FINISH STILL YIELDS SUPERB RESULTS by Jeff Jewitt [http://antiquerestorers.com/Articles/jeff/shellac.htm]

Indranil Banerjie
12 May 2012