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Why is Measuring Powder Coating Thickness Important?

Posted on: March 13th, 2018 by byersbushblog

When you get a professionally applied powder coating finish, you observe the beautiful and uniform film-like finish that it has. This coating not only forms a protective barrier over the material but is also a way of enhancing its beauty. Unfortunately, when the powder coating is too thick, it can have a negative effect on the finish. Let’s take a look at some important details of powder coating.

powder coating thickness

The Powder Coating Process

Not many people know that the extremely popular powder coating process was introduced in North America during the 1960s as a type of dry finish procedure. Today it has captured 15% of the entire industrial finishing market because the process can be used on a wide range of products and materials.

Companies that are looking for durable and high-quality finish are specifying the use of this procedure over other coating processes. This is primarily because it can deliver improved efficiency, maximized production, and simplified compliance with environmental requirements.

With its functional and decorative finish, customers are treated to an endless or close to limitless options when it comes to textures and colors. The technological advancements in applying powder coats have resulted in excellent finishes as well as improved performance properties.

Powder application processes

How exactly does the powder application work? In terms or powder coating, the powder can take the form of polymer resins that are combined with pigments, leveling agents, curatives, flow modifiers, as well as other additives.

The ingredients are then melt mixed before it is cooled and grounded into a uniform powder appearance like baking flour. The application processes rely on Electrostatic Spray Deposition (ESD) to ensure that the coating sticks to the metal substrate. A spray gun is used to gain electrostatic charge for the powder particles so that it is attracted to the grounded material.

The powder coating will initially be applied to a small portion of the metal to undergo adhesion testing. This is to ensure that the powder will stick properly to the metal and yield the desired result. Once this has been established the material can then be completely coated and cured to apply additional heat.

The resulting molecular chains that have high cross-link density are commonly resistant to break down. The finish can be used in a variety of metals including non-metallic substrates like medium density fiberboard (MDF) and plastics.

There is a coating thickness standard that is commonly observed to ensure that the coating is durable, beautiful, and lasts for a long time. The coating thickness often is determined by the way that the powder is applied to the material.

Commonly, the powder can be applied with the use of an electrostatic or corona gun. The gun creates a positive charge on the powder to allow it to stick to the negatively charged material. There are different types of nozzles that can be used for electrostatic coating. The shape of the material will determine the type of nozzle to use. Preheating can be used as a pretreatment process to get a uniform finish and avoid potential problems that can result in imperfections on the finish.

Powder coating can also be applied with the help of a fluidized bed. The preheated material can be dipped in fluidizing powder until the coating melts and flows to cover the entire material. This process can require post curing depending on the temperature and mass of the material including the type of powder used.

powder coating process

Importance of Coating Thickness

Generally, thinner coats are considered weaker than dense finishing. It also prevents the optimized high-quality finish from forming because of the potentials for surface defects and sharp edges. The excessive coat is also not ideal because it damages the uniformity and is considered a waste of material. Uneven curing can be expected when there is too much coating and can also be a sign of amateur work.

Professionals know how to use techniques and tools that can allow them to evaluate the thickness of the coat. Many of these are used before the material goes into the curing stage. Coating providers also rely on information on hand like the type of material used to make a determination on the thickness of the coat.

When there is too much powder coat, it can lead to quality control issues; something that is undesirable in a commercial setting. The excessive coat can also degrade the basic functionality of the material that is being protected or cause problems during its assembly.

There are nondestructive gauges that are used to measure the thickness before the material is sent into the oven for curing. It provides the flexibility to pause or reverse the electrostatic process until the proper powder coating thickness standard is achieved. The guidelines of the resin manufacturer can also be used as a basis.

Take note that there are some process variables that will have an effect on the thickness of the powder coating procedure. These are not limited to the type of gun as well as the electrostatic power supply used. The operation scale will also be a contributing factor together with the powder guns and baths, which will affect the consistency of the coat. Meticulous technicians often rely on in-house processes to identify thickness tolerances and control the product quality.

Since powder coating can be applied to thousands of potential products, it is essential to understand the properties of the material before going through with the process. This will ensure that only the toughest high-quality finish can be produced on even the toughest machinery possible.

The toughness of powder coating is better compared to liquid paints while measuring up to its visual appeal. In terms of resistance to fading and rust, powder coating is likewise ahead on both counts and provides better protection against impacts, moisture chipping, scratches, abrasions, chemicals, corrosion, ultraviolet light, and other issues that can result in coating wear. Its friendliness to the environment is an added benefit that many customers would definitely subscribe to.

Powder Coating Blasting

This is an alternative way of removing the powder coating. It is considered safer and easier compared to chemical stripping. Abrasive blasting is the process of removing powder coating in a quick and powerful manner without having to worry about technical skills or any other issues.

When mistakes are uncovered on the finished powder coated product, there is no other solution but to remove the coat and start over again. Blasting gives you a quick way out becomes in only 30 seconds per square inch, the powder coat can be completely removed. This efficiency is attributed to its unique abrasiveness combined with its adjustable power. It is as simple as it can be; all you need to do is point and shoot and the coating will be stripped without having to resort to complex procedures.

How do you do this quick and safe way of removing powder coating? First off, you do not have to buy any toxic chemicals so it is completely friendly to the environment so it complements the powder coating process. Second, you just need to make sure that you have the proper protective gear available before you start blasting away on the material.  Here is how you do it:

  1. Start by putting on the protective glasses and ear plugs. Shot blasting can create quite a noise so you need to protect both your eyes and ears.
  2. The blast nozzle should be aimed directly at the powder coat. The material coming from the nozzle is highly pressurized so it can cause some damage if aimed at someone.
  3. Press the switch to activate the nozzle and the powder coat will simply tear away from the material.
  4. Rinse the surface of the material using rust inhibitor and water. If necessary repeat the process to ensure that the entire surface is completely cleaned.


Once the powder coated material is sent into the oven, the curing process begins. The curing process is characterized by the use of high temperature that is designed to cause the powder to melt and flow across the material to achieve a perfectly uniform finish.

Once the powder reaches the ideal temperature, the cured film coating is achieved. It will then be allowed to cool off before it is checked for imperfections and consistency. When thermosetting materials are used for curing the predicted cure undergoes an additional reaction. The material that is coated with the continuous liquid film will experience a continuous increase in temperature while inside the oven.

The underlying heat hardeners are activated once the curing reaction begins. Maintaining the cure temperature for the proper duration will result in the proper curing of the powder coat. The predicted cured thickness will likewise be achieved for that impact resistant and tough finish. Note that there are substantial differences between liquid and powder coats.

powder coating blasting

Source: Pfonline

When using powder ovens, the material should reach the optimum temperature quickly. This allows for maximum flow out before any curing reaction can gel the film. For liquid ovens, a slow heat-up would be ideal to prevent the solvent from boiling into the paint. This difference means that powder ovens allow for shorter and cheaper application of the coat. Less energy is likewise required for the powder oven compared to its liquid counterpart.

There is an evaluation process that must be observed when doing powder coating. As the powder coat is exposed to the heat, the cure will proceed in a variety of stages.

  1. Pre-Melt – in this initial stage the freshly applied powder can still be scratched off easily. A low-moderate air hose will allow you to chip sections should you find the need to do so. The topcoat may also be applied at this stage, but it is not usually advisable to do so.
  1. Continuous Film –you begin to observe a tight orange peel smooth appearance. The film normally will have a higher gloss compared to the cured powder. The product has the ability to reflow once exposed to heat but can be shattered by any significant impact.
  1. Gel – at this stage the powder has already achieved a continuous film form due to the reactions that have taken place. It can no longer reflow and any significant impact will result in severe cracking accompanied by moderate adhesion loss.
  1. Pre-Cure – this is the stage where the coating has achieved initial impact resistance. There can still be apparent cracking and slight adhesion loss. Higher gloss level is achieved compared to that of the cured film. Chemical resistance is relatively poor at this point.
  1. Full Cure – optimal film properties are present at this stage with chemical interaction minimized. This means that full inter-coat adhesion is less likely to occur.
  1. Over Cure – when you reach this stage you can observe the film losing some flexibility. It may turn yellowish in color and can exhibit a decrease in gloss. The inter-coat adhesion will be compromised with coating failure becoming highly likely.

Throughout the process, you will have a way of evaluating the proper thickness of the expected coat. This will ensure that the final cured thickness remains desirable and optimal.

If you want to make sure that you get the best powder coating results without having to deal with high prices and potential risks, contact Byers Bush Powder Coating today!

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