This Wednesday’s word is Lacquer. We are going to tell you precisely what it is and the properties it has.
Lacquer, What Does It Mean?
Today we are adding to the glossary with the word lacquer. I had planned to submit both lacquer and varnish, but decided, as I did with shellac, it was too much info for one post. So, lets get the pared down definition out of the way, then I will give you some background on it.
Lacquer – A finish for wood furniture that is solvent-based, high VOC, quick drying with a high gloss. It is rated at moderate to good durability. A lacquered finish is easy to repair, which makes it a good choice for some applications. It comes in three sub-types: Nitrocellulose, Acrylic-modified and Catalyzed. Each of the three types have specific qualities that depending on your project, would determine the sub-type you would choose.
Lacquer was developed in the 1920’s and proclaimed to be the ultimate wood finish! While time did prove that to be a bit of an exaggeration, it still has a place in wood finishing today. The finish is always sprayed (rarely brushed) and applied in a single coat, as it has a low solids ratio and the solvents dissolves the previous coat to form a single coat. It is resistant to alkalis, acids and water making it hard wearing. Being fast drying is a plus but being high VOC content is a drawback. (The high VOC content is why we do not offer a lacquer.) Nitrocellulose lacquer (usually simply labeled lacquer) yellows with age. The high gloss is perfect for some projects but would be considered a con on other jobs.
- Nitrocellulose: It is the most common type and is made from nitrocellulose resin and an alkali which are dissolved into each other, then that mix is combined with a quick evaporating solvent. It yellows with age, had poor scratch resistance and is heat sensitive. It has moderate resistance to water and to certain solvents.
- Acrylic-modified: Made from a mixture of non-yellowing cellulose resin (CAB: short for cellulose acetate butyrate) and acrylic. Generally, it has the same properties nitrocellulose lacquer with the exception of yellowing. It does not yellow. (Acrylic-modified is also known as CAB lacquer.)
- Catalyzed: Catalyzed lacquer has the ease of application as the other types but improves on the durability of the other types. It comes in two types, pre-catalyzed and post-catalyzed. The pre-catalyzed is mixed by the manufacturer or at the point of purchase. The post-catalyzed is a two-part system, meaning two components must be precisely mixed shortly before use and giving it a short pot life. Both are a very durable finish which is made possible by an acid catalyst that is added to a mix of either urea formaldehyde or urea melamine and an alkyd nitrocellulose resin.
Looking for a great tutorial on how to repair this finish? Frank Ford demonstrated it well in his blog post on FRETS.COM. Frank is an esteemed guitar repairman. You can find the how-to here.
Like shellac and varnish, lacquer is often used in a generic way to mean the finish (especially when it is a high gloss finish) on a furniture piece. While for many conversations, the generality is acceptable, however, there are some instances in which you must clarify if they really mean a lacquered finish or just a gloss finish. They are always made from nitrocellulose and a solvent. If you use the word lacquer to describe a finish, for the sake of your professional reputation, use it correctly.
Varnish is the next word we will define and probably the most misused of the three: shellac, lacquer and varnish. See you on a future Wednesday!