After investing a lot of time and effort in specifying timber veneer for your project, it is essential to finish it with an appropriate lacquer or coating. This serves to protect the timber’s natural beauty for as long as possible. In the case of veneer, beauty is skin deep! Typically veneers are only about 0.6mm thick, therefore sanding it back at a later date to restore its aesthetic is not an option.
There are a number of ways to finish timber, including oils, lacquers, shellac, wax and paint. Not all are suitable for timber veneer, like oil, which can affect the veneer’s bond to its substrate. This blog will look at clear finishes for timber veneer, which are used to contribute to the overall aesthetic, as well as help the veneer cope with the demands of its intended use. But what it really boils down to for most people is wanting their timber veneer to look as good as possible, for as long as possible.
In choosing a finish you must balance use, aesthetic, durability, safety and maintenance. Attention must also be given to the timber species and the timber grain as both have implications for finish selection. For example, some species have tannins and phenols in their makeup so a special coating needs to be applied to create a barrier to stop the chemicals in the timber reacting with the top coat used to finish it.
Historically, people have used various finishes on timber including wax, varnish, shellac and oils which have had varying degrees of success. They were not without their limitations, which centred around longevity of protection and a tendency to yellow and/or stain veneers over time. The first lacquers came onto the scene around 1920 and, with technological advances, have steadily improved. These improved formulas have given users more options and flexibility allowing for a more individualised result, rather than a one lacquer fits all approach.
Lacquers can be clear or coloured and deliver different levels of sheen from matte through to very high gloss. Acrylic, polyurethane and solvent based lacquers are the most widely used. Lacquers made from acrylic polyurethane are best for use on engineered and natural timber veneers. Acrylic polyurethane offers excellent durability and resistance to heat, water and yellowing. Typically you would use it for kitchen doors/panels, bathroom vanities, high-end commercial and domestic projects, venetian blinds and shutters, table/bar tops, and hotel/office fittings.
Polyurethane lacquer is also very good on engineered and natural veneers, with the same applications and levels of durability as acrylic polyurethane. It also offers excellent heat and water resistance, however it does yellow. The degree of yellowing varies and is dependent on the brand. Other options for the applications mentioned above include water-based two pack and low volatile organic compound (VOC) polyurethane. Both are excellent performers with regard to resistance to heat, water and yellowing; however water-based two pack is not quite as good as low VOC polyurethane in terms of durability.
There are also UV curable coatings that offer excellent heat, water and yellowing resistance as well as durability. Mainly used for flooring, flat pack furniture, vanities and kitchen panels, UV curable coatings are good for engineered and natural veneers. Other options include water-based single pack; acid catalysed, and pre-catalysed. Acid and pre-catalysed lacquers are older technologies that do not perform as well as newer lacquers. Pre-catalysed lacquer yellows significantly and acid catalysed lacquer can change the colour of substrates.
As you can see there are a number of options for finishing timber. Veneer panels require some type of seal or coating, so when specifying it for your project it’s best to rely on the advice of your panel layer. In making a recommendation they will consider what the best finish is for its end use. It is also important to use the same coating across the entire project to ensure consistency across the panels with regard to ageing and wearing over time.
Image courtesy of APR Joinery – Boardroom table with Zebrano Veneer laid in diamond pattern with black tulipwood veneer edge and matching sled base.
