What Are the Differences Between Mural Lacquer & French Polish?

French Polish is a method of applying shellac.

There are many different methods of applying sealants from spraying to painting to blotting with a cheesecloth. There are also many different types of sealants. Selecting the proper substance and application can drastically change your results. Knowing the difference between organic and man-made sealants can also help your project. Always apply your sealant, regardless of the type, in a well-ventilated area as many of them use toxic solvents that can be hazardous if breathed.

Differences

French Polish is a method of applying shellac. Mural lacquer is a finish applied to pieces of canvas artwork. The main difference between shellac and lacquer is that shellac is organic, where as lacquer is man-made.

Shellac

Shellac is a natural product of the lac bug which inhabits South East Asia region of the world. The bug deposits secretions on tree limbs which workers then harvest, dissolve in denatured alcohol and purify. There are different purification levels for different applications. Shellac is a fast-drying sealer and is commonly used on furniture, especially in antique restoration efforts.

Since it dries quickly it is less likely to crack like lacquer. Shellac is most commonly brushed onto the surface, or blotted on with a cheesecloth (the French Polish technique). It can also be sprayed. Additionally, shellac is much healthier for the environment than lacquer as it does not use many of the hazardous solvents commonly found in the other finish.

Lacquer

Lacquer first underwent development after World War I. Polymers, such as nitrocellulose were dissolved into volatile organic compounds. When the solvents evaporate the lacquer hardens, creating a very durable finish. Lacquer is a very common finish and is used on everything from musical instruments to children's toys and even in the automotive industry. It is typically applied with a spray gun. Artists use specialty lacquers to protect and seal their work.

Varnish

In addition to lacquer and shellac, varnish seals many things. In fact the term varnish has become a colloquialism referring to any general type of sealant. Varnish has two basic categories: oil and acrylic. Oil typically has a longer drying time and is recommended for commercial use. Its acrylic counterpart is ideal for indoor uses. Along with being quicker drying and durable, water works as a solvent thereby making cleanup much easier.

References

• Arslanian Restoration: What is the Difference Between Lacquer and Shellac?
• Art Sparx: Sealers and Sealants