Spray stain, the process to make color in the finishing

Stain is the finishing material to make color. Most of stain application for wood furniture today is done by spray. With the proper spray technique, we can layer the stain to color the wood surface according to the wood condition to get the finish color we want. The problem of the wood variation in color can easily be handled by spray application. The spraying process is also much faster then the wiping and brushing. However the proper spraying application is needed to produce the good coloring result. There are several point must be considered to get the proper spray stain to meet the good finishing result. They are: the unfinished preparation, the equipment preparation and selection, the stain preparation and the spray stain execution. 

•  Preparation to the unfinished wood.

The most important wood preparation is the wood sanding. The wood sanding must be done correctly to produce a good performance finishing. The white wood sanding must be started with the coarse sandpaper and gradually followed with the finer grade. The final sanding for finishing preparation should be ended with the # 240 or # 180 sandpaper. For more explanation you can read our previous article : How to sand the unfinished wood  .And to help the check the wood sanding you can go to our article: How to inspect the unfinished  wood furniture 

•  Preparation of the spray gun.

The proper spray gun is needed to produce a good layer stain. Check and clean the spray gun that is going to be used to spray your stain, make sure it works well, do testing with paint thinner and see the results. For wood stain application, the air spray gun is the best choice. It can produce the best atomization. It is also very flexible for adjustment and setting, with fully control by the operator. The HVLP or LVLP spray gun are also can be used, although they are not as flexible as the air spray, but they can produce good atomization and quite well adjustable. The airless spray gun or air mixed spray gun is not proper for stain application since its limitation in control and setting. But most of all, the spray gun must be in the good condition to get the good staining result. You can view more about spray gun in our previous article: The spray gun for wood furniture finishing

• Preparation of the stain.

To get the correct coloring, then we need the proper stain. Wood stain is a thin solution which is rarely damaged, but of course we have to check it to ensure that the stain is in the good condition before being used. Stir and agitated the stain to let the pigments perfectly mixed. Check the physical performance of the stain, it must be well mixed without any sediment or dirt inside. We may need to filter the stain to clean from the dirt or slurry.  

Check the stain color; make sure we got the correct color. The stain may be changed in color due to its solvent evaporation. The stain with low quality may even get color changes because of chemical reactions or pigment degradation. The stain colors can be checked by pouring it in the pour down on the card, wood panel or wood veneer. See our previous article: How to check the stain color

• The spray stains technique.

The stain is needed to be applied properly to produce the correct color finishing. We should coat the stain with proper thickness to the wood surface for the right coloration.  The wood may have varied base color; then we may need to layer the stain differently for each part to get the even finish color. Use the sap stain and equalizer to equate the wood base color before apply the overall body stain. See our previous article: how to match color in the wood furniture finishing

After an even wood base color is obtained then we need to view the overall basic color of the wood, and make sure that we use the right stain color to produce final color finishing what we want. We can use the color wheel diagram to determine the color of the body stain we need.
There are three techniques spray; dry spray, medium wet spray and wet spray. Wet spray technique is the most recommended because it produces the best surface wetting. Wet spray also gives the highest efficiency in material transferring. However, in some cases, the medium wet or dry spray is needed. Dry spray is needed for the application of equalizer stain and sap stain to handle the variation of the wood base color. While the medium wet spray is needed for stain application to the soft woods like pine, maple, sengon, etc. to minimize the risk of blotchy color when stain is applied too wet.
Spray stain with the correct technique; make sure the stain coat the surface with a uniform staining to the overall surface. Start to spray stain on the bottom or the inside part or other invisible part, then do the spray on the visible part. The main part furniture as top panel or the front should be sprayed at the last time. To see more about spraying technique, you can go to our previous article: How to use the spray gun  and how to set the spray gun
Do some experiments on some pieces of wood panel to make sure we apply the stain correctly before making application for the big furniture product.
Check the stain layer after the application. Make sure the stain layers the wood surface evenly with the proper color. Make correction if the color is uneven, too light or too dark. We can also make correction or revision in this step if there is any problem on the wood surface such: glue spot, scratches, dents, gap, etc. The stain layer that has not been covered with clear coat still can be cleaned easily. We can darken the light stain by re spray the stain, or lighten the stain little bit by rub with steel wool. We can also easily remove the stain layer by wash it off with thinner or sanded with sandpaper. 

The stain application is the first finishing process that will form and built the base finishing color. It is very important to do the proper wood staining to get the even stain layer with the right color. Then we can continue the finishing process by another finishing operation, the sealer, glaze and top coat application.