What can you Powder Coat?
Although powder coating and traditional painting both have their place in the manufacturing industry, powder coating as a technique has several advantages over solvent-based paints.
Due to the thermal bonding of the particles during the curing process, powder coating is more resistant to chipping, scratching and other types of damage related to wear and tear when compared to normal paint. The technique allows for much thicker layers to be applied when compared to solvent based paint. Heavier coats provide longer color retention and extended protection especially for products that will be used outdoors.
In general, powder coating offers significant advantages when compared to the alternative, but the process cannot be used with every material. In this article, we will discover which substances are appropriate for powder coating and which substances are not.
Suitable materials for powder coating
Powder coating employs electrostatic force to apply the powder to the surface of the material in question. Each particle within the mixture is charged by a magnetic coil before it is forced out of the spray gun by compressed air. If the object receiving the coat is properly grounded, it will attract the particles to its surface due to the magnetic charge.
Metal
Metal is far and away the most electrically conductive material known to man. This ability to receive a charge makes metal objects ideal candidates for powder coating.
Although conductivity is an important factor in the powder coating process, the curing stage requires materials to be heat resistant in order seal the coat. On top of being highly conductive, metal is also capable of withstanding the high temperatures required to bring about the thermal bonding which binds the particles in the powder together. These combined factors make metal an ideal candidate for powder coating.
Thousands of household products that we use everyday have been powder coated before being packaged for retail. Those products include:
- Stainless steel coffee cups
- Refrigerators
- Lawn Furniture
- And so much more
Wood
For many years wood was considered unsuitable for powder coating because of two key factors: Low thermal conductivity and an inability to conduct electricity. As most of us are aware, wood doesn’t work well with electricity, and it burns when heated. However, there are a number of powder coating techniques and innovations that can be used to overcome these drawbacks.
When applying a powder coat to an object, an electric charge is required to draw the powder to the surface. Without a charge, the coat will just fall to the ground. To apply a powder coat to charge resistant wood products, the solution to the conductivity problem is to pre-heat the item before applying the coat. Wood is capable of withstanding mild exposure to heat, and hardwoods such as oak are even more heat resistant. When the coat hits the pre-heated wood product, the particles melt and stick to the surface.
As we can see, the preheating technique is an excellent solution to the conductivity issue, but this is only one half of the powder coating process. The curing stage requires high-heat to bring about the thermal bonding which gives powder coating so many advantages over traditional paint.
Powder coating has come along way since its invention, and now there a number of low cure powder coatings that are ideal for coating wood. These coats, unlike their predecessors, only require temperatures around 250 degrees(f) or less to cure the coating.
Pre-heating and low cure powder coats enable a wide score of wood products to be considered suitable for powder coating. Due to these innovations, wood products are regularly treated with powder coats and we use them every day.
Medium density Fiberboard (MDF) is the most common wood material to receive powder coatings. This is because MDF is less porous than untreated wood and its surfaces are very smooth.
Powder coated wood products include:
- Furniture
- Cutting boards
- Doors
- Cabinets
Glass
Much like wood, glass is a poor conductor of electricity. There a few techniques that manufacturers use to overcome this issue. Hot flocking is a preheating technique used in the industry to preheat glass. It is also possible to coat the inside of the glass with aluminum or copper to trick the particles to sticking to the surface of a glass object, but most professional powder coaters consider pre-heating the best option.
Glass is able to withstand some heat exposure much like wood, so to get the best coat selecting the right powder is important. As we mentioned earlier, low temp curing powder coats are available in a variety of forms, so contact your local provider to discover which coat is right for your project.
Glass products that can be powder coated:
- Bottles
- Windows
- Jars
Plastics
Traditionally, plastic was not considered ideal for powder coating, but due to the recent developments we discussed above, it is possible to powder coat some plastics, but this is highly dependent upon the plastic being treated. Some plastics are capable of withstanding high heat, but not all. Be sure to carefully select the plastic material you intend to powder coat and contact your supplier if you have any further questions.
Powder coated plastic products:
- Shipping crates
- Office furniture
- 3D printed objects
Materials that aren’t ideal for powder coating
Heat resistance and conductivity are the two main factors to consider in regards to selecting a suitable material for powder coating. These conditions alone eliminate a wide swathe of substances from contention. Although there are a number of ways to overcome these hurdles, many materials are simply unsuitable for plastic coating.
Surprisingly, there are a great deal of metal products that can’t be powder coated, those include parts made using resin or plastic body fillers. These materials resist conductivity and melt under high heat.
Materials that can’t be powder coated:
- Rubber
- Most plastics
- Raw and porous wood
- Anything that melts at a high temperature
The brilliant and vivid finishes achieved using this technique have made powder coating an ideal finish for both large scale manufacturers and DIY crafting enthusiasts the world over. Due to the alternative techniques discussed above, powder coating is no longer limited to metal. As the industry continues to progress, more and more products will become suitable for powder coating.