Black Powder Coating

One of the most preferred surface treatment techniques in the rapid prototyping industry is powder coating which provides improved physical and mechanical characteristics to the custom machined parts. This coating technique which has its origin from the early development of powder metallurgy has received a lot of acceptance in the recent past. It is widely utilized in the modern industry because of the following advantages: high corrosion protection, fine surface finish, and long-enduring, eco-friendly impact.

This article will take a closer look at the various kinds of powder coating, how the process is done, and some useful tips for a perfect powder coating. This is where you will find all your answers concerning black chrome powder coating, and sprays.

What Is Black Powder Coating Finish?

Powder coating is a process of applying dry powder on the surface of the material and then using heat to set it. The powder that is employed can be thermoplastic or a thermoset polymer powder. This method forms a strong and long-lasting layer which is stronger than the liquid varnish and ideal for use on plastic, glass, and metal.

Powder coating is usually done by electrostatic spray deposition (ESD) or fluidized bed technique. Both methods provide high gloss, different kinds of surface, a wide range of color and high quality of the surface. Because of these characteristics, powder coating is applied in many industries such as medical, architectural, automotive, fiberboard avionics, and many others.

The Different Types of Powder Coatings

Another effective painting technique that provides a very good and quite a durable coat is called powder coating. Whether you are a first time user of powder coatings or you have been using it for a long time, you will find it very strong and versatile. It remains the same from having one spray gun and a small oven to running a large line with automation. Here’s how it works:

A powder spray gun is used to spray the powder particles and at the same time charges them with an electrostatic charge. The grounded areas draw the charged powder on it to ensure that an even layer of the powder is achieved. After the powder application, the parts are taken to an oven where the powder melts and fuses to the surface giving the part a hard, scratch resistant, and aesthetically appealing surface.

It is mostly used on metals and for this reason it is very useful. Some of the areas that apply black powder coating spray paint are the industrial parts, medical equipment, architectural structures, automobiles, bicycles, home appliances, furniture, enclosures, trailers, and lighting among others. The possibilities are endless!

Powder coatings are of different types; and each type has its own features and uses. The type of powder to be used should be chosen before the color to be used is chosen. It is, therefore, necessary that one knows the characteristics of the different types of powders to be able to get the best outcomes.

The last advantage of powder coatings is that it does not have solvent at all in its formulation. This means no organic volatile compounds or VOCs are emitted, making powder coatings safer to apply, to get rid of and to ship than liquid paints. This is a green factor that has a lot of advantages to the environment for both the user and the customer.

Epoxies

Epoxies were the first powders in the market and are still widely used due to their high level of hardness. They provide excellent hardness and are reported to have better chemical and corrosion resistance than the other available powders. Another benefit of epoxy powders is that they are easy to apply and are available in many cure schedules. Epoxies cure very well on metals particularly when the metal has been prepared by methods like phosphate coating and sand blasting.

However, one of the main disadvantages of epoxy powders is their rather low resistance to the effects of natural factors. Epoxies when left exposed to the outdoor environment turn to fade and chalk under the sun and the surface turns bad within few months. This limitation makes epoxies more appropriate for interior use where they are protected from the UV light.

However, due to high adhesion and good corrosion resistance, many primers are based on epoxies. When applied as a base coat to another type of paint they offer a strong base, utilizing their advantages but at the same time minimizing their vulnerability to sunlight.

Polyesters

Polyesters are the most popular powders in powder coating since they are cheap and can be used in most applications. There are two main types: TGIC and TGIC-free, called ‘Primid’ In general, both types have good mechanical properties such as flexibility and impact strength, and good chemical resistance. Polyester powders also have the advantage of low curing temperatures, which makes them ideal for use on items that cannot be exposed to high temperatures.

Polyesters also do not overbake and do not yellow and are easy to apply on different surfaces. Standard polyesters have UV resistance of 1-3 years and are used for indoor applications as well as some outdoor applications. Another essential aspect of polyester powders is the ability to vary the color, gloss and the special effects, which makes the list almost endless. Owing to their good general characteristics, polyesters are used most often in various coating processes.

Fluoropolymers

In architectural uses, fluoropolymers are chosen for their high resistance to weathering, excellent color stability, and high surface gloss. They are highly appreciated in exterior applications like curtain walls, windows, and doors. The two main types of powder coatings that are commonly used are FEVE and PVDF. PVDF fluoropolymers always need a primer, either a liquid or powder and are difficult to bond when developing metallic powders. The FEVE resins are much more preferred by the powder coating fraternity due to their exterior durability in a single coat. FEVE based fluoropolymer metallics are developed to achieve uniform dispersion of metallic particles in the powder so that the surface application of the powder is smooth.

Polyurethanes

Polyurethanes are chemically very similar to polyesters but the curing agents are different from polyesters. It offers a very smooth surface and good shield against environmental conditions and is very immune to chemical and corrosion. These qualities make them suitable for use in such areas as fuel tanks. They are also used in tractors, air conditioning systems, car wheels and doors for example where the low fingerprint factor of the material is valued.

However, polyurethane paints have some demerits; at high thickness, they emit gases and turn into a hard substance. Application and curing can result to smell and there is likelihood of smoke formation during curing thus it is advisable to control application and curing conditions. Polyurethases are generally more costly than other types of powders mainly due to the cost of the resin.

Pros of Black Powder Coating

Durability:

Powder coated surfaces are extremely scratch resistant, they do not blister, crack, peel, flake or wear as quickly as painted surfaces. This makes them ideal for application in places where force and hard wearing cover is needed like in automobile and aircraft industries.

Cost-effectiveness:

Powder coating is slightly costly in the initial stage of painting as compared to wet painting but in the long run it is cheaper. It does not need frequent refinishing and it lasts longer than the painted products in the long run.

Quality Finish:

Powder coating is a process that offers quality and durable coatings with a shiny and glossy finish. It provides better finish to the products and provides better protection against corrosion and weathering to give a longer lasting and attractive finish.

Environmentally Friendly:

Powder coating is environmental friendly as it does not require the use of solvents and does not release any dangerous gases or chemicals or volatile organic compounds. The application of the coating is not in any way a threat to the environment and the only by product that is formed is the powder which can be reused.

Versatility:

Powder coating has a very large range of colors and types of finishes that allow coming up with unique designs. It can be used on metals, plastics and composites, thus it is suitable for use in many industries and for many products.

Cons of black Powder Coating

The limitations of black powder coated finish include;

Higher Initial Costs:

The setting up of a powder coating facility requires a lot of capital investment due to the type of equipment and materials used. However, the costs of powder coated surfaces are slightly higher than the costs of wet painted ones But this is offset by the fact that powder coated surfaces are more durable than wet painted ones.

Color Limitations:

Therefore, powders cannot be mixed at the site to create new colors as is done with the wet paints. This means that each color has to be applied individually, which somewhat hinders the immediate availability of colors. However, powder coatings come in standard colours, which are adequate for most of the design needs.

Minimum Coat Thickness:

The thickness of powder coatings should be at least 40-60 microns for the best result. This makes them less suitable for use in areas that require very thin layers of paint as the wet paints may enable one to better control the thickness and application of paint.

Touch-Up Challenges:

It is important to note that it is relatively difficult to touch up powder coated surfaces as compared to wet painted ones. It is normally a complete repainting and not spot repainting since the touch-ups normally require a proper approach which requires proper tools and equipment.

Complex Application:

The process of powder coating must be controlled and maintained to certain parameters such as temperature and humidity. This is to mean that issues like variation in thickness or bonding issues can be realized if not managed well and it calls for professional operators.

Selecting a Color for Your Industrial Object

Choosing the right color for your industrial product may not be a big issue if you are already aligned to a specific brand color. However, the number of choices available for powder coat finishes is quite large which can be confusing. No worries! Below is a detailes on gloss and texture especially for black coat finishes with the help of our consultant, from CNM

Black Powder Coating Gloss Finishes

1. Matte

A matte black gloss, which is also called “flat,” has very little to no shine. This finish actually ‘eats up’ light instead of bouncing it back, thus making the surface look a little bit classy. It is best for applications where the product needs to be matte and does not reflect light, for example, some car components or industrial machinery. The absence of shine also assists in covering up small surface flaws and gives a uniform surface texture.

2. Satin

Satin black gloss is a little less flat than matte. It has a dull, fuzzy luster and is not as shiny as a glossy finish but has a more refined look to it. This finish is ideal for products that require the middle ground between looks and functionality such as electronics or home appliances. The gloss is not too flashy and gives a contemporary feel to the space and it is not overly difficult to clean.

3. Medium Gloss

It is darker than the previous two and has a clear reflective shine to it but not as glossy as the high-gloss black. This finish is between the satin and the full gloss in terms of the level of reflection. It is ideal for applications where a moderate gloss is required for the furniture and fixtures in offices and commercial buildings. The medium gloss improves the looks of the material while providing reasonable wear and tear and also it does not attract fingerprints and smudges easily.

4. Full Gloss

Gloss black with no intermediate coat is very shiny and reflective, in fact, they are comparable to a mirror. This level of gloss is typically applied to products that need to be eye-catching and make a statement such as automobile accessories, trims, and handles, ornamental items and other premium products. The clear reflections improve the aesthetics, although this finish is more susceptible to revealing surface blemishes, so the surface must be well prepared and well maintained.

Black Powder Coating Textures:

1. Sand Texture

A texture in black powder coating that looks like sand is rough like sandpaper; it has a gritty surface that you can feel. This texture is restricted to low gloss levels and is generally not more than 20 gloss on the gloss meter. It is best for products that should reduce the reflection of light but at the same time, provide a distinctive and tough surface. The sand texture also provides a good feel and surface traction and can be used on tools, outdoor equipment or industrial equipment.

2. Hammer Texture

Hammer texture black finish has a rough surface with a depressed appearance like a hammered metal or an orange peel. This texture is usually used with higher gloss levels, but the texture lowers the reflective clarity by itself. It is widely used in decorative applications where a durable, shiny surface is required, like in construction machinery, outdoor furniture, or car parts. The hammer texture gives the building personality and also conceals small irregularities on the surface.

3. Wrinkle Texture

A wrinkle texture in black coating is a little tighter and rougher than the sand texture. This texture gives a different feel to the product and also increases its grip and its life span. However, wrinkle textures cannot be used in conjunction with high gloss levels and are normally utilized in applications that call for a hard wearing non-sheen surface. It is ideal for the electronic enclosures, control panels and other products which require a professional and robust look.

In this way, the consumer can make a proper decision about which of the available gloss levels and textures of black powder coat finishes is most suitable for a specific product in terms of its function and appearance. If you need a shiny, smooth or a matte, rough appearance, then there is a black powder coating solution for you.

Tips To Get Optimal Black Coat Finish

To get a perfect powder coat finish one has to be very careful and follow the right procedures as recommended. Here are five essential tips to ensure your powder coating process results in a durable and attractive finish:

Surface Preparation

Preparation of the surface is the key to achieving the best powder coat finish. Any form of dirt, grease or rust on the surface of the material hinders the proper adherence of the powder. First, wash the surface carefully, then abrade it to make it flat and free from any debris. Preparation is critical because it will greatly improve the bond and the lifespan of the powder coating.

Selecting the Right Powder

It is worth to note that various projects call for different types of powder coatings. One has to choose the right powder material depending on the application of the final product. Some of the conditions that need to be considered include the type of environment that the coated item will be subjected to and the characteristics of the desired finish. If you are still in doubt about which powder to use, seek advice from a professional on which material to use.

Avoiding Edge Buildup

Edge buildup or known as picture framing is a condition where there is an excessive buildup of powder at the edges of the component. To counter this, make sure that the spray gun settings and movement are uniform in order to achieve an even coat. Do not point the spray gun at the edges and try to keep a fixed distance and movement pattern.

Correct Handling of the Coating Gun 

It is also important to use the powder coating gun correctly in order to get an even coat. Make sure the tip of the gun is appropriate for the job – the tip should be small enough to prevent the powder from flowing out unevenly, but large enough to prevent over-spray. Furthermore, corrected voltage settings will help to make the powder stick to the surface and not bead up or give inadequate coverage.

Effective Curing Process

Baking is an important process that hardens the powder coating and provides it with a durable layer. When using the manufacturer’s curing times and temperatures, make sure to adhere to them to the letter. This is normally done by heating the coated item in an oven at a certain temperature for a certain period of time. Once the curing process is complete, it is advisable to examine the surface of the powder coat for flaws or any form of irregularities.

Wrapping Up

Dry film finishing technique is of two types, one is powder coating which has been in the market and in use today and it involves the use of finely powdered pigments and/or resins to give the required degree of gloss and smoothness. This method is more durable than painting and comes in many colors and finishes. However, it is not an easy task, work, skills, and experience to master the art of powder coating but you don’t have to worry.

At CNM, we provide professional touch up services that will enable you get the best of the powder coating. The professional team offering the best and cheap services in surface finish for various industries with experience. Let us enhance the aesthetic value of your parts and at the same time enhance their functionality. To start your project with CNM, please attach your CAD files, and get an instant quote.