Wood Staining, a coloring process for finishing wood

Wood staining is the process of applying stain in the finishing process. Wood stain generally refers to a coloring material (stain) that penetrates into the wood and coloring the wood without covering the surface of the wood. As coloring material, the wood stain is different with base coat, or primer, which is covering the wood and forming a solid color (opaque) finish. 

The wood stain work to built the wood color but still keep the basic character of the wood. The wood stain is used to make the transparent finish, the finishing colors that still show the grain, pore patterns and enhance the natural beauty of the wood. The final color of the finishing is the result from the combination of the base color of the wood and the color of the stain. You will need the right stain color and the proper application to get your target color. Proper wood staining will produce a beautiful finishing color appearance without losing the natural beauty of the wood

The function of wood staining

- Beautifies the appearance of wood  

The light color wood mostly is considered cheaper than the dark color wood. Wood staining make the light wood to be darker and be looked as the expensive wood. It will increase the aesthetic value of the wood. The wood stain, is the tool to direct and change the wood to get the desired color and appearance. The wood staining can also enhance the grain and pores to more dramatic and make the wood to be more attractive and artistic.

- Increases wood durability

Wood naturally tends to change color over time. Chemically, wood will react and change color when exposed to light. The application of stain will make the color of the wood to be more stable. The pigment absorbed by the wood will protect the wood by reducing the intensity of light absorbed by the wood. Stained wood tends to be stronger and more durable than natural wood, the darker color is more stable with the light stain color. The outdoor wood products that will be exposed to sunlight and outside weather, is highly recommended to be stained with the right material. The natural wood (no stain) is easy to get color change if it is exposed to the outdoor.  

- More choice for product color  

The wood staining will change the color of the wood to the desired color. With large variety stain, then many options of colorings are available.  Wood staining allows to accord your wood products to follow and adapt to the design. The wood staining let you to create attractive visual harmony in the interior decoration.

- Enhance and beautifies the natural character of wood

By selecting the right type of stain and application method, wood staining will not only improve the color of the wood, but will also strengthen the grain and pore pattern of the wood. Wood stain that penetrates into the pores and grain will magnify the wood character, grain and pores.

Types of wood stains

- Oil-Based stains  

Oil stain is a wood stain that uses oil as a base and solvent. Oil base stain is generally applied by brushing, or wiping although it can also be applied by spray. The oil solvent allows the stain to penetrate into the pores and grain of the wood and color it deeply. The oil stain is the best stain to maximize and enhance the natural grain and pores of the wood.

- Water base stain  

Water base stain is used water as the main solvent. It is considered as the more environmentally friendly and safer material. This water base stain can be applied by brushing to let it penetrates into the wood and enhance the grain and pore patterns of the wood. But the water base stains generally dry faster than oil base stains, that make his grain effect is not as strong as the oil base stain. The water base stain is fast drying material, that make it easily applied by spray and also suitable for mass production that require high speed process.  

- Solvent base stain

There is some type of solvents can be used for stain. The solvent base stain usually dry faster than the oil base and water base. The solvent base wood stain is usually applied by spray in a modern spray finishing process even the slow solvent may be chosen for dipping or brushing application. With the right solvent, the wood stain can be adjusted in drying time and application method to fulfill the mass production process.

- Outdoor wood stain

Outdoor stain is a stain made with pigment and binder from materials that are resistant to UV rays and outdoor weather. This stain is designed for coloring wood products for outdoor use so that the resulting color does not fade quickly and lasts longer.

Things that need to be considered when applying wood stain

- Selection of the stain type

The choice of this type of stain will affect the appearance of the resulting finish. In general, the slow drying stain will let it to penetrate deeper into the wood. This type of wood stain will maximize the grain and pores pattern and produce a more natural looked color. On the other side, the quicker drying stain will make the stain stay on surface of the wood and less in showing the grain and pores pattern. Base from these two facts, then you can choose the stain type according to your appearance needs.

The other consideration in choosing the stain type is the function of the product be finished. For outdoor products, wood stain must be the outdoor type that is resistant to heat, UV rays and outdoor weather. But the usually the outdoor stain is more expensive and rather limited in color option. If you do for the indoor product, then you can use the indoor wood stain that will give you more color option and less expensive.

- Variations of the wood base color

Wood is a natural product that has variation in properties, including its base color. The variation in the wood colors will result in different color results if you do the same wood stain application. If the variation is too far, then you may need to change the color stain. It would be very troublesome, especially when you do finish for mass production. To minimize this problem, you can add step to evens out the wood base color before the wood staining. You can use the sap stain to bring the light color to the dark color and (or) the equalizer stain the kill the of bright spot color and make the wood color to be even all over the product..

- Variations in wood porosity

Wood also has variations in porosity or wood absorption properties. The wood porosity is related to the absorption of the wood stain. Wood with high porosity will absorb more stain so that the resulting color tends to be dark, conversely the wood has low porosity will absorb less stain so that the color to make the light color. To anticipate this problem, it is necessary to have a good knowledge about the type of wood and its properties. Make sure you use the right stain type and application according with the wood properties to make the desired finish. If necessary, you can use the wood conditioning or sealer sizing to make the wood more uniform before stain application

- Stain color selection

The function of wood stain is to form the color of the wood, therefore choosing the color of the stain is very crucial important to bring the color to the desired result. For white wood, the stain color is made according to the desired final finishing color, for example to make brown color you can use the brown color stain, to make the red finish color you will need the red color stain. But because wood has its own basic color, then the choice of stain color may be more complicated. You have to consider that the final color is produced from mixed from the color of the wood and color of the stain. To help choose the right  wood stain color, you can use the color triangle principle in our previous post..

- the stain application

Wood stain can be applied in several ways, by dipping, brushing, wiping or spraying. Stain application by dipping and wiping and brushing is a simple process but the results is rather limited and less control to the layer and thickness. The resulting color will highly depend to wood the condition and the stain. The spray application is a modern application and considered the best way until now. The spray method gives the high control to the coloring results. You can adjust the coating layer and the thickness of the stain layer to control the color obtained. 

- Drying of the stain

After the stain is applied to the wood surface, the next process is the application of a clear coat (sealer and top coat) to provide protection for the resulting color. Before the clear coat is layered, the stain must be dry especially when the stain solvent is not the same type with the solvent of the coat. For example, if you use the oil stain or water base and coat it with the solvent base coating. The clear coat will build a film coat that will cover the stain underneath. Any solvent remaining on the wood will be trapped under the coating layer and could causing finishing problem. 

- Wood preparation

The other thing needed in the finishing process is the wood preparation. Any problem in the unfinish wood will make your finishing bad in quality. Sanding the wood properly, make sure the wood surface of the wood must have smooth and even surface. The rough and uneven surface will result in unequal absorption, resulting in uneven coloring result. The wood defect such as dent, scratches, mark will be more clearly visible after stain application. Therefore, repair and correct any wood surface problems before the stain application. 

- Develop a step panel before application the stain to the big product or big volume production

The wood stain application process is one step in a series of finishing processes. Usually the application of stain is always accompanied by the application of other materials such as the application of sealer, top coat and other finishing materials. Make sure you know the final results of the finishing process before the staining process is carried out. It is highly recommended to make a step panel as a guide for all finishing step taken in the finishing process. When you have the step panel done, you can get the standard of your finishing process needed to meet your target finishing looked and color. Then you can follow your finishing step to finish your product or run your finishing production to make your finishing color and looked. To find more information about step panel, you can visit  our previous article : step panel for furniture finishing