What is French Polishing / Shellac and How Does it Work?
French Polishing is a technique used to protect and bring out the natural beauty in wood. The material used to do this is called shellac.
What is Shellac?
Shellac comes from a resin secreted by the Lac beetle (which lives in trees in India and Thailand) to form its cocoon. The colour of the shellac varies according to the species of tree the beetle lives on, and ranges from a deep garnet through orange to pale yellow.
This resin is dried and then made into a solution in alcohol - this is liquid shellac. Shellac was confined to the Far East until traders introduced it to Europe in the 1700s; however it wasn't until the 18th century that the technique of using shellac was refined by the French - hence 'French Polishing'.
Furniture from the Georgian and Regency era - and most certainly Victorian furniture - will have been French Polished or sealed with a shellac.
Why Use Shellac?
Two reasons: protection and appearance. Wood furniture needs to be protected against conditions such as humidity, sunlight and everyday wear and tear such as water marks. Shellac also enhances the appearance of the timber.
The rich colour and distinctive figuring of the grain in the wood is brought to life, leaving the wood with a beautiful lustre and sheen. Shellac can also be used to change the colour of the timber, hide blemishes or repairs to damaged surfaces and dramatically improve the appearance of a plain piece of furniture or wooden fixture such as a staircase or wardrobe.
Although shellac is less durable than a modern lacquered finish, unlike lacquers it can be efficiently repaired and restored.
What is actually involved in French Polishing?
The polish is applied as a liquid mixture by either a polish mop (made from bear or squirrel hair) or by a pad/polish rubber made up of wadding wrapped in cotton.
Once spread over a surface, the polish forms a thin, solid coating. The changeover from a liquid that is relatively easy to apply to a tough, well-adhering film, is accomplished by the liquid portion (solvent) evaporating, leaving behind its solid component (resin) as a thin film coating the wood.
The French Polisher applies the initial coats by polish mop in the direction of the grain. The surface is then sanded down using a very fine abrasive paper to ensure it remains smooth, and to prepare for application with the polish rubber. The polish rubber is moved across the surface in the direction of the grain, starting with small light figure of eight movements, from the centre outwards. The stroke shape and pressure is gradually increased as the rubber applies the shellac to the surface.
This process is repeated many times. As every new (and extremely thin) coat of shellac is applied, its alcohol solvent melts the uppermost part of the hardened film already on the wood. This makes for excellent bonding between coats.
The goal is to achieve layer on layer of shellac, filling in all the wood's pores so that a thin, perflectly flat film covers the entire surface of the piece.
What Woods Respond Best to French Polishing?
Dark, fine-grained woods such as Mahogany, Walnut and Rosewood benefit the most from French Polishing. Not all wood types require such a lengthy process for finishing. Oak, for example, (which is a rustic and coarse grained timber) is best left unfilled. Pine and Teak prefer a low lustre finish, which is achieved using waxes and oils.
Is It Worth It?
After over 25 years working in the trade, using the same methods utilised by craftsmen hundreds of years ago, French Polishing still continues to impress. You can see before and after shots of our work on most pages - just click one of the links below.