Working with Stains 7/10/2012 10:00:00 AM
Stains provide the color and much of the beauty that a finished piece of wood work has. How they are used will not only affect the aesthetic qualities, but also the durability of the entire finish system.
Stains are typically not durable coatings in themselves. We use them to provide color for the wood work and the potential for durability problems must be overcome with the other finishes used. Stains not only contain pigments to provide color, they have other ingredients that improve the durability versus pigments or tint pastes alone. However this is still not as durable as the sealers and topcoats.
Stains come in a variety of types: wiping, spray no-wipe (toner) (spray to color stain), dye, etc. Each type has potential durability issues that need to be prevented. Some of the common durability problems that arise from misuse of stains are listed below.
Using a wiping stain as a spray no-wipe stain is a common problem. Wiping stains are meant to penetrate into the wood and then be wiped clean. An excess of wiping stain can lead to poor adhesion of the finish coats or lifting (wrinkling) if two coats of catalyzed material are applied over it. “Dirty wiping” a wiping stain can also cause the same problems. If a deeper or darker color is desired than the wiping stain can provide, a toner or dye stain may need to be used in conjunction with the wiping stain. This provides the color depth and prevents durability issues.
Another common problem is using the wrong type of stains and finishes or mixing different suppliers products in the finish process (i.e. using manufacturer A’s wiping stain, manufacturer B’s sealer, manufacturer C’s toner, and manufacturer D’s topcoat). Manufacturers test their products together so they can recommend finish systems that have been tested for not only aesthetic qualities, but durability as well.
Over-tinting a stain is common when finishers tint their own colors. It is important to keep within the recommended amounts and type of tint pastes for a specific product. There are many types of tint pastes and they are not created equal. “Universal” tint colors are not universal for all applications. It is important to use the recommended type of tint pastes for the stain you are tinting. Not only are stains typically not durable in themselves, tint pastes are even less durable. So over-tinting can make the final finish system fail even if the stains are applied properly.
Another problem is when a solvent is tinted instead of an appropriate stain base. Again, too much tint paste is a bad thing. When only a solvent is used as the stain base you should expect the durability of the final finish system to be decreased.
Working with stains in the manufacturer’s recommended guide lines will help you produce appealing products that are durable.