How Much Heat Can Powder Coating Withstand

How Much Heat Can Powder Coating Withstand

How Much Heat Can Powder Coating Withstand 

Powder coating is the process of applying a dry coating to a surface as an alternative to using a liquid medium (such as paint or a solvent). The powder is made-up of several different components that are mixed together and processed into a solid mass which is then broken down and granulated into a powder that is finer than salt.

Powder coatings offer a good degree of resistance to heat, as well as UV rays and chemicals, the question now is How Much Heat Can Powder Coating Withstand?

The crucial thing here is to be clear what your end application is, and match it with the right kind of powder coating that will offer sufficient heat resistance.

There is a range of materials you can powder coat for heat resistance, includ\\ing:

Metal

Wood

MDF

Glass

Composite materials

Why Do Surfaces Need Heat Protection?

Exposing substrates to heat can damage them, with surface breakages and corrosion. This kind of damage can also come from rapid fluctuations in temperature.

There are numerous items, products and surfaces which benefit from surface heat protection, enabling them to withstand high temperatures.

These include pipework and chemical plants, chimneys, engine components and outdoor furniture and architectural features.

Heat resistant Powder Coatings offer the following benefits:

Protection from corrosion – applied to steel surfaces, powder coating provides an added layer of protection between the surface and its insulating layer

Resistance to abrasion – powder coating makes substrates suitable for challenging environments

Reducing thermal fatigue – powder coating extends the life of machine parts and improves performance

Enabling higher operating temperatures.

Various categories of heat resistant powder coating can provide effective thermal protection for substrates, withstanding temperatures up to 550°C.

High temperature powder coatings are usually silicone based.

They also are free from volatile organic compounds (VOCs), making them environmentally friendly and easy to both transport and dispose of safely.

Choosing a High Temperature Powder Coating

It is important to consider the needs and function of the substrate you wish to protect with powder coating:

What is the maximum temperature it will need to withstand? High temperature powder coatings will perform well, but only within the temperature range they are designed to tolerate. You will find that each type of powder coating will have a specific temperature range.

Is the surface you are coating insulated? Corrosion under insulation (CUI) is a particular issue in some industries. In these circumstances, the coating must provide corrosion resistance but also be able to deal with application to hot surfaces.

What will the temperature of the substrate be during application of the powder coating? Some powder coatings are formulated for hot temperature application (around 300°C), and some for ambient temperature application. For instance, will it be possible to shut down operations to apply a powder coating?

There are these other factors to think about too:

Will the coated surface prevent a spread of flame should a fire break out? The relevant standard here is BS 476 parts 6 and 7.

How combustible will the coated surface be? The relevant test here is European standard EN 13501-1. This also applies to the following two considerations.

What is the smoke emission of the coated surface?

Will the coated surface release particles into the air during a fire?

How Does Powder Coating Work?

This granular form allows the powder to be evenly applied to a surface in a consistent manner. The dry powder is electrostatically charged and sprayed onto the surface needing coated. Once the powder has been thoroughly applied, the newly-coated part is placed into a curing oven. This is where the powder melts and adheres to the part, creating a smooth, hard coating.

Advantages of Powder coating

Powder coating has several advantages over liquid finishes. Generally, powder materials are less expensive and less labor-intensive to produce, which makes it a more affordable choice. The quality of finish that’s offered is very durable and provides exceptional resistance to heat, chemicals, extreme weather, and corrosion, in addition to a consistent finish that doesn’t drip or run. Powder coating is also very environmentally friendly - compounds aren’t evaporated into the atmosphere because the airborne powder is easily filtered and has low health risks for employees. 

Frequently Asked Question about Powder Coating

Can you use a heat gun to cure powder coating?

The curing process for powder coating is normally done in a special oven; the coating has to be exposed to a temperature range of 350 to 400 degrees Fahrenheit (160 to 210 degrees Celsius) for 20 minutes. When melting the more common thermosetting powder, it bonds chemically to form a hard, permanent layer of paint. Thermoplastic powders harden, but if they are heated again, they become malleable and only harden again when they cool.

To cure powder coating, both the powder and the substrate have to reach the desired temperature and stay there for the allotted time without any temperature fluctuations. For this reason, the best way to cure powder coating is with a curing oven. However, a kitchen oven works just as well, as long as you don't plan to use it for cooking food ever again. For small items, a toaster oven is just as good. While some people may choose to use a heat gun to melt the powder so that it stays in place while the item is transferred to an oven, a heat gun can't produce the necessary stable, all-encompassing temperature required to cure powder coating.

Why choose powder coating?

Powder coating is currently the fastest growing coating technology because it provides resilience that traditional paint options don't. Powder coating is more resistant to chips, abrasions, UV light, petroleum products (gas, oil) and chemicals than solvent based "wet" coatings. Further, it is able to withstand higher temperatures which makes it ideal for engine parts and because it is applied electrostatically it is always uniform, with no runs or drips. Powder coating is also environmentally friendly, and there are no hazardous materials used for cleanup.

Is powder coating flexible?

Indeed it is. This makes it the ideal solution for flexible parts like automotive springs, hinges, and other parts that undergo frequent wear and tear processes.

Does powder coating protect against wear and tear?

Powder coatings provide superior protection against all sorts of threats, including solvents and chemicals such as gasoline, oil, battery acid, and more. They are also less prone to wear and tear from weather and moisture, and are far more resilient than traditional solvent based coatings and paints. 

Types of Powder Coating

There are three main categories of powder coatings: thermosets, thermoplastics, and UV curable powder coatings. The UV curable powder coating is a new technology.

Most manufacturers examine costs and potential coating complexity when deciding which type is most appropriate for their application. In each of these classifications, there are a variety of sub-groups, and each individual powder is engineered for specific finish qualities.

Conclusion

In general, powder coating can withstand temperatures far in excess of the capabilities of standard paint. This makes powder coating ideal for applications such as engine or exhaust parts, or any part that gets excessively hot. For some parts subjected to extreme temperatures, such as some engine parts, a high temperature powder may be required.

Powder coatings can provide effective heat resistance, withstanding temperatures up to 550°C. However, you must choose your coating carefully, to ensure it matches your end application.

In order to properly powder coat a surface, it must first be clean. Meaning you cannot powder coat over an existing finish, including any chrome finishes. However, we at GZ Industrial Supplies offer high quality powder coating services and cleaning systems to ensure that your product is completely clean before being coated.

Aluminum, bronze, copper, brass, titanium, and steel (including stainless, galvanized, anodized and e-coat) can all be powder coated. If the metal can hold an electromagnetic charge and withstand the heat from the curing process, it can be powder coated.

As you can see, there are plenty of benefits to choosing a powder coating. If you’re looking for a finish that is durable, looks nice, and is cost-efficient, powder is the coating choice you want to make.

Whether you are looking for multiple colours, a high quality durable finish, or corrosion protection, please contact GZ Industrial Supplies to discuss your requirements. 

13th Nov 2020 Anthony Ubong

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