Ultimate Guide to Powder Coating
When it comes to finishing and protecting your sheet metal fabricated products, powder coating is one of the best options on the market! But what is powder coating? How does it work? And why should you choose it?
At Salamander Fabrications, we’ve been mastering the craft of powder coating on our metal fabrication projects for over four decades. At this point, we’d confidently say there’s nothing we don’t know about the process and are committed to ensuring our customers can rely on our quality sheet metal products for years to come.
In this guide, we’ve rounded up our expertise and put together everything you need to know about powder coating. You’ll find out:
- What powder coating is
- Exactly how the powder coating process works
- Different types of powder coating available
- Choosing the right colours and finishes
- The pros and cons of powder coating vs paint
Got a specific query? If you’d like more than just to read about it, get in touch with our friendly team on 01484 843599 or at sales@salamanderfabs.com and we’ll be able to give you tailored advice to meet your precise needs.
What Is Powder Coating?
Powder coating is a colour-finishing technique used on thousands of different everyday materials, including sheet metal, concrete, steel and plastic surfaces.
Powder coating is often used instead of traditional liquid paints. It can be used indoors and outdoors, and offers a high-quality, long-lasting and durable finish to products of all shapes and sizes!
Examples of powder coating application for everyday products:
- White goods like fridges and freezers
- Stands and display units
- Cars and auto assembly parts
- Indoor and outdoor furniture
So, How Does Powder Coating Work?
Powder coating, as the name implies, uses a dry powder instead of traditional paint. This powder is sprayed onto the objects to be coated and is then heated and cured to form a harder, thicker and more consistent coating than painting.
This protective coating can be used in indoor and outdoor applications. It continues to be extremely popular as a manufacturing process due to it ticking many boxes. It is:
- Water resistant
- Heat resistant
- Weather resistant
- Corrosion resistant
- Impact resistant (to a degree)
It also creates a uniform finish and a customised visual appearance.
The Powder Coating Process – What Is Powder Coating Application?
Powder coating is a dry finishing process that can be carried out on many different products or structures. As sheet metal fabricators, we at Salamander usually work with powder coating on metal, but it can also be applied to other materials such as concrete, plastic, etc., to protect them from the elements.
Powder coating requires a considerable amount of equipment, but the process itself is relatively simple. Broken down into five easy Cs:
Step-by-Step Powder Coating Process
- Cleaning – The material surface needs to be manually cleaned, as well as go through a chemical cleaning. This ensures that any grease, dirt, imperfections or oils have been removed and that the surface is as smooth as possible. This will help the powder coating finish stick to the structure.
- Coating – The product is then coated, usually using a powder coat gun, which is a type of spray gun. Polyester powder coating (or other materials) uses an electrostatic gun application method, which coats the entire surface of the product.
- Charging – The metal product is connected to a power unit, which helps the powder particles attach to the metal as they are shot out of the gun. The power unit gives off an electrostatic charge, and the powder particles are then attracted to this charge, helping them stick for a smooth finish.
- Curing – Finally, the coating is cured, which is where a chemical reaction takes place. During the heat curing process, the powder melts slightly and bonds with itself to create a strong coating. In some cases, powder finishes also bond with the metal to improve the durability of powder coats. This curing happens in a specialist ‘oven’, which heats the coated surfaces to around 200°C for 20 to 30 minutes (product dependent).
- Cooling – The structures are then allowed to cool which further strengthens the bonds before they are ready to be shipped out. The dry powder coating process is now complete!
Different Types of Powder Coating
Sometimes, the question ’what is powder coating?’ isn’t as easy to answer, as there are so many different types of powder coating! Depending on the type of finish needed, powder coating can be made with a few different materials. Polyurethane, epoxy, polyester and acrylic are some examples of commonly used powder-coating materials.
Thermosets and thermoplastics are the two main types of powder coating. While the process used to carry out thermoset and thermoplastic coatings is largely the same, the materials used mean there are significant differences in the end result.
Thermoplastic Coating
Thermoplastic coatings become liquid during the heating process, which means they don’t actually chemically bond to the object being coated. This makes the coating reusable, reversible, and thinner than thermoset powder coating.
For objects that might need to be recoloured, recycled or reused in a different context, thermoplastic coatings are a better option.
Thermoplastic coatings typically provide a thicker layer, which makes them more durable when compared to thermoset powders. This type of coating is used more regularly on household items, automobile parts and metal objects.
Thermoset Coating
Thermoset coatings are a thinner type of coating. When cured, thermoset powder chemically bonds to the material it is coating, which means that it cannot be recycled, but also makes it less prone to chipping or cracking.
The key advantage of thermoset powder coating is that it is incredibly heat resistant, so it’s very suitable for protecting metal structures in high-heat areas.
Choosing the Right Colours and Finishes
One of the advantages of powder coating is the incredible range of colours and finishes that are available. Most powder coating providers will stock a range of colours (using RAL colour codes), making colour ordering quick and easy! Each RAL colour is also available with a few different levels of gloss, creating even more options!
Gloss particles can be added to most colours to provide different levels of shine. Unlike RAL colours, however, gloss levels are not uniform across manufacturers. It’s the brand of coating powder used that will impact what gloss and textures are available to you.
The team at Salamander Fabrications are highly experienced and can work with you to create a finish that works perfectly for your products, regardless of colour or brand!
Gloss Finish
Gloss finishes are the most popular in the industry, and have a gloss level of about 70%.
This kind of powder coating has a great level of shine and you can see reflections of most things, though they aren’t super-defined. It isn’t a mirror finish, but it does have a lovely reflective surface.
It is also very easy to clean due to the smooth surface!
High Gloss Finish
A high gloss finish will help your structures stand out no matter what! These surfaces have gloss levels of above 80% and offer a smooth, incredibly easy-to-clean surface.
Important to note, however this application process will result in visible imperfections if the underlying material isn’t completely smooth. This means that more surface preparation is required before the process of powder coating can be carried out.
Matte Finish
Matte or flat powder coating has a low gloss level – usually around 30%. It will reflect light in some capacity, but you won’t be able to see clear reflections, and only in high levels of light.
That the matte coating nullifies reflection to this degree is great for products that might have some smaller surface imperfections on the metal – they will be hidden. However, matte coating can be harder to clean than some glossy surfaces so this is worth bearing in mind.
Matte coating is great for use in areas like offices and retail as, though cleanliness is important, the standard is not incredibly rigid. However, in industries – such as the science or food industry, where powder coating is commonly used – where cleanliness is of great importance or where cross-contamination is possible, a matte finish is less ideal. This is because the textured matte surface can have tiny crevices or dips, which make it trickier to clean.
Sand Texture Finish
As well as matte, gloss and high-gloss finishes, texture can be added to powder-coated products. Like matte finishes, textured finishes are great for hiding any imperfections in the underlying product surfaces and are also great for providing additional tactile support (improving accessibility) and grip/friction (particularly on outdoor surfaces).
Sand texture is the least obtrusive texture and is fairly similar to matte textures. Sand texture, like the name implies, feels like sandpaper to touch.
Wrinkle Texture Finish
Similar to sand texture, wrinkle texture is slightly rougher. It has a lot of surface area due to raised grooves, bumps and wrinkles in the surface texture. This makes it excellent for use outdoors and provides a strong level of grip where needed. Wrinkle texture is usually the roughest option when powder coating products and is great for use in industrial applications.
Hammered Texture Finish
Hammered texture finishes have a similar level of texture to wrinkle textures, but with a higher gloss finish. It is very durable and allows customers to request a gloss finish without having to worry about any imperfections on the metal surface of the product.
For this reason, it doesn’t need as much surface preparation when compared to gloss coatings.
Powder Coating vs. Paint
One of the follow-up questions we often hear after ‘What is powder coating?’ is ‘Is it better than conventional paint?’, and it’s a good question!
There are lots of different factors that can affect which coating is the right one for your project, but, in general, spray painting is more affordable upfront, while powder coating is a more efficient, high-quality and long-lasting product.
- Durability – One of the biggest advantages of commercial powder coating over spray paints is the protective feature that powder coating technology provides. Powder coating creates a hard, solid layer that encases the object it is applied to and protects it from heat, cold, ice, water, UV rays, bumps, scratches and dents. Powder coats are not only more durable than paint coats, but they also help fabricated products last longer.
- Environmental impact – Unlike some traditional spray paints, powder coating doesn’t release volatile organic compounds (or VOCs) into the air. It’s actually a very eco-friendly process, as any excess powder can generally be reused, and thermoplastic coatings are also recyclable!
- Range of colours and textures – There is a vast range of powder coat colours and textures. While spray paint finishes also have a range of colours and gloss/matte options, there is no way to emulate sand, wrinkle, or hammered textures with paint.
- Cost efficiency – While paint coating is cheaper upfront, powder coating services are very cost effective when looking at their lifetime cost. While the process of application and protective gear needed for powder-coated parts is more expensive, the lifetime costs are relatively similar.
- Wastage – There is also considerably less wastage associated with powder coating, as excess powder or powder that doesn’t stick during the coating process can be reused again. With spray paint, any wastage is lost and cannot be reused.
- Quality of finish – As powder coating uses electrostatic processes to cure the coating, the finish is generally smoother and more consistent. When painting an object, the paint may run down the sides or be coated unevenly, whereas powder coating guarantees a smooth metal finish.
Powder Coating with Salamander Fabrications
At Salamander Fabrications, we’ve been working in sheet metal fabrication and the powder coating industry for over 50 years. We pride ourselves on our expertise and attention to detail when it comes to all aspects of the projects we undertake, including powder coating metals to help strengthen them, protect them and create a high-quality finish.
To learn more about the work we do or to get started with your next project, please don’t hesitate to get in touch with our friendly sales team on 01484 843599 or at sales@salamanderfabs.com.
