Dust Spray Problem in the Wood Finishing

The dust spray problem is the rough surfaces caused by dust particles that attach to the finishing surface. In some severe cases, the dust spray can appear as a surface with an uneven gloss that can look like a zebra. The rough surface directly reduces the quality of the finishing, especially if it is anchored with an uneven look. The good-quality finishing must have a smooth surface and even look. The dust spray problem should be avoided and minimized to give the good quality finishing. 

 the dry spray

The dust spray problem is mainly caused by the poor spray technique. The application of paint, top coat, or sealer always needs a wet and evenly coating layer to the overall surfaces. The uneven coat (dry spray) will produce a rough and uneven surface since there is dust attached to the surface. 

The best way to avoid the problem of dust spray, is by doing a good spray technique. A proper spray technique will produce a wet coating layer on the entire surface evenly and result in an even and smooth finish. But even though the spray technique seems to be the main factor, in fact there are also some other factors that should be carried out to remedy the dust spray problem. There are some other factors that need to be considered, such as finishing material quality, spray equipment, the shape and size of the product, and the finishing room. 

Here are the things that must be considered to avoid dust spray

Actually, the dust spray problem is a minor problem; it can easily be repaired and corrected with a simple method. A thin dust spray in the exposed part can be fixed by doing scuff sanding on the rough surfaces. But a severe dust spray on the wide and face surfaces, especially with a high gloss, can only be revised by resanding and recoating the whole surface. But it is always better to avoid the problem instead of repair it. Here are some things you can do to minimize the dust spray problem.

• The finishing material adjustment

The finishing material has to be perfectly atomized when it is applied and layered to produce an even and smooth coating layer. To be perfectly atomized, finishing material should have viscosity according to the type of spray equipment used. Check the viscosity of each mixture of the finishing material before it is applied, and make sure it is according to the specifications of the spray equipment. The h.v.l.p. spray gun usually requires material with low viscosity (14 second NK 2 cup), while the air spray gun and airless spray gun can work with a higher viscosity material (up to 18 second NK 2 cup). Each tool type and brand can have its own specifications, so we may need to do consultation with equipment suppliers and find the viscosity needed by the equipment. Then do the adjustment to the material in accordance with the spray gun to be used. Materials with too high viscosity can be thinned by adding some thinner. Use an appropriate paint thinner to reduce the viscosity of the material. The good-quality material finishing mixture is a big help to getting a good finishing result.
Instead of the proper viscosity of the finishing material, it also requires a proper drying time to avoid dust spray. A material layer should be wet for quite a long time to make sure the layer has enough time to receive the material dust spray during a spraying process. The wet layer will let the dust spray stuck is dissolved and merged with the surface layer and does not generate rough surface. Ideally, a finishing layer of the first stroke spray gun is still wet until the last stroke is done. The coating layer must remain wet until the last stroke of the spray gun movement, so the dust spray from the spray gun movement will be able to be accepted and mixed by the surface finishing layer without causing a rough surface.
For a wide and big surface, for example, such as a big cabinet, or a wide and long table, it is sometimes rather difficult to be fulfilled. You may need to adjust the finishing material to dry slower. You can add some retarder to the mixture to slow the material's drying time when you do big objects. But you cannot set the drying time too long. Too long drying time will slow the finishing process. Too long drying time will also risk affecting the gloss and getting problems with dust.

• The setting and selection of the spray gun.

To produce good coating material, a proper spray gun is needed. To produce the perfect material coating, the spray gun has to produce the perfect atomization and send material to the surface evenly. You need a suitable tool to do it; the spray gun size needs to fit with the surface area of ​​the object. Adjust the width of spray according to the width of the surface object. Too narrow spray spreading width will require many strokes and be difficult to produce an even layer. Choose the type and size of spray gun according to the type of goods and the volume of work. The air spray gun can generate the most perfect atomization but you still need  the  proper-sized equipment. You cannot use the small cup gun to spray to the big volume job or big objects. The air spray gun with pump or pressure port is better to be used since it can make a spraying can be done continuously. For big volume job the air assisted spray gun is good option since it is more effective tool to do the high speed spraying process.

• The spray techniques

The poor spray technique is often the main reason for the failure of the finishing material application. This spray technique is a skill that needs adequate training and exercising in sufficient time to be mastered. To be successful in the spray application, you need operators with enough skill that can only be obtained with enough practice. The main principle in the spray coating is that the coating layer should be wet enough (as wet as possible), but do not let the finishing material sagging. It is more difficult to be obtained when you spray on objects with complicated forms, such as chairs, a crib, or a large cupboard. But with enough practicing, every person will be able to master the best spray technique  according to each model and item. As a basic knowledge of spraying technique, please view it in our previous article: how to use a gun correctly.

• The finishing and drying room.

A rough surface finish can also be caused by dust that falls and sticks to the surface while the layer is still wet. A good spray technique needs a finishing with a wet layer, but if the wet surface is exposed to the air, there may be some dust that falls to the surface finish and generates a rough surface. Therefore, you also need a finishing room and drying room that are clean and free of dust to place the wet-coated product.