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Which One is The Best: Powder Coating or Liquid Coating?

Posted on: July 18th, 2018 by byersbushblog

Is there significant benefit in choosing between powder and liquid coating? Obviously, there are many factors that can be considered to establish whether one is indeed better than the other. If we consider for example that both processes are factory applied using controlled and stable conditions, will there be a difference aside from the price? Let’s try to see.

Sandblasting

Regardless whether you choose powder coating or liquid paint, the first step is to clean the surface to be coated. This normally involves sandblasting to clear any mill scale, rust, oil, and other impurities from the material. Even if you will recoat an old material, you will still use sandblasting to remove the old coating.

Different medium can be used for sandblasting, which can be anywhere from biodegradable to steel grit. The medium can be reused so that you do not have to keep on buying. The length of time it takes to finish the cleaning would depend on the extent of work to be done. Once finished, the material must be stored in a dry environment.

liquid coating

Liquid Coating Overview

This makes use of carriers, additives, resins, and pigments. The additives are responsible for the special characteristics of the finish like UV protection and rust prevention. The main liquid is known as the carrier, which is the product of the paint formulation; this can be solvent, water, or a combination of both. Pigments affect the gloss of the finish, the more pigment, the less gloss there is. Resins on the other hand act as the base for the liquid paint.

Basically, once the area has been sandblasted, the liquid coating will be applied using a spray gun. Normally, a primer is applied beforehand as a layer of protection. The main coat may be applied 2 to 3 times depending on the need and preference. A Class A finish normally describes the quality of the coating, but not necessarily its durability. The more mils applied to the material, the better the protection there is. It is always wise to balance maximum protection and minimum paint mil thickness.

Powder Coating Overview

Before powder coating is applied, the area will be negatively grounded to ensure that the positively charged powder will stick to it. The powder will be sprayed using an electrostatic gun to achieve uniformity and least thickness possible.

After the material has been completely coated, it will be moved from the powder coating booth to the oven so that it can be heated and turn the powder into gel. Make sure that the material is moved slowly to ensure that the powder remains on it and no surface defect will be seen on the finish. The length of time that the material stays in the oven will depend on the volume of the metal that is being coated.

When the primer has gelled up a finishing coat will be applied. The finishing coat will depend on the preference of the customer, but will be applied in the same manner as the primer. The material will be baked once more until the powder is completely cured, and a beautifully strong finish is achieved.

Benefits of Powder Coating over Liquid Coating

Economically, powder coating offers more benefits in the sense that its average transfer efficiency is around 60% to 70%, with the excess or over spray reclaimable and ready for reuse. This means that you eliminate possible waste. In liquid coating, the transfer efficiency is about 30% to 35% at the most with about 50% of the product lost to evaporation; you cannot reclaim this. Base product of powder coating is comparatively cheaper than that of liquid coats.

Application of both powder and liquid coats require substantial precautionary measures to prevent irritation and other possible risks. However, the task is significantly easier to do with powder coats because you are dealing with solids. There is also no chemicals or VOCs unlike in liquid paint. This translates to environmental advantages for powder coating since there will be less hazard to landfills, prevent depletion of the ozone, and does not deal with hazardous waste materials.

As far as the thickness of the final coat is concerned, that of the powder coat is at least twice as thick compared to liquid coat. The real benefit though can be seen in the flexibility of the coat, which allows you to bend and yield powder coated materials. For automobiles, this translates to less risks as the materials are subjected to tremendous and repeated twisting and vibration. Powder coats also stand up better to rock chips and other potential damages that can be caused while on the road. This does not mean that powder coats are indestructible, only that it offers better protection than liquid coats.

Powder Coating

From a production standpoint, powder coats take considerably less time to cure. Once the coated material comes out of the oven, curing can be expected in as short as 20 minutes, which means that the product is already ready for use. For standard liquid coats, it can take days to achieve a complete cure depending on prevailing weather conditions. Even if the powder coated material has not completely cooled off, you can put it to work immediately without worrying about destroying the finish. In terms of efficiency, with less waste, less risks for runs, fewer incidences of defects, and no over spray, powder coating has definitely the advantage.

The Downside

Although the benefits of powder coating clearly outweigh those of liquid coating, it is necessary to be aware that it has some shortcomings as well. The most common issues that have been raised against powder coating are:

  • Difficulty in matching metallic colors of paint;
  • High costs of running a curing oven;
  • Rubber products cannot be coated because it melts; and
  • Touch ups are quite challenging.

Most of these issues can be addressed by carefully designing and engineering the production process. In fact, if you make sure that an experienced and professional powder coating provider will do the job, then all of these issues should be of no concern to you.

So literally, we can say that in the battle between powder coating vs liquid coating, the obvious winner would be the powder coating process.

If you want to make sure that your powder coating is done right, then contact Byers Bush today!

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