Powder coating is a type of dry coating, which is applied as a free-flowing, dry powder. The main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form. The coating is typically applied electrostatically and is then cured under heat to allow it to flow and form a "skin." The powder may be a thermoplastic or a thermoset polymer. It is usually used to create a hard finish that is tougher than conventional paint. Powder coating is mainly used for coating of metals, such as "white goods", aluminium extrusions, and automobile and motorcycle parts. Newer technologies allow other materials, such as MDF (medium-density fibreboard), to be powder coated using different methods.

The application of powder is very simple. Filtered, compressed air, usually at 20-30psi pushes the powder out of the gun past the electrode which gives the powder a positive charge. The part being coated is grounded so the positive powder particles are attracted to it. When the part is completely covered, the ground is taken off and the part is put into the oven.

The powder coating process involves three basic steps:

1. Part preparation or the Pre treatment
2. The powder application
3. Curing

Part Preparation Processes & Equipment
Removal of oil, soil, lubrication greases, metal oxides, welding scales etc. is essential prior to the powder coating process. It can be done by a variety of chemical and mechanical methods. The selection of the method depends on the size and the material of the part to be powder coated, the type of soil to be removed and the performance requirement of the finished product.

Powder Application Processes
The most common way of applying the powder coating to metal objects is to spray the powder using an electrostatic gun, or Corona gun. The gun imparts a positive electric charge on the powder, which is then sprayed towards the object, which is grounded. The object is then heated, and the powder melts into a uniform film, and is then cooled to form a hard coating. It is also common to heat the metal first and spray the powder onto the hot substrate. Preheating can help to achieve a more uniform finish but can also create other problems, such as runs caused by excess powder. See the article "Fusion Bonded Epoxy Coatings"

Curing
When a thermoset powder is exposed to elevated temperature, it begins to melt, flows out, and then chemically reacts to form a higher molecular weight polymer in a network-like structure. This cure process, called crosslinking, requires a certain degree of temperature for a certain length of time in order to reach full cure and establish the full film properties for which the material was designed. Normally the powders cure at 200 C (390 F) in 10 minutes. The curing schedule could vary according to the manufacturer's specifications.

The application of energy to the product to be cured can be accomplished by convection cure ovens or infrared cure ovens.

Although, some non-conductive materials such as abs/nylon plastics, ceramics, porcelain, and glass can be powder coated, the most common powder coat candidates are metal objects that can hold an electrostatic charge. All surfaces must be able to handle the heat of the curing process.

Powder can be applied to complex surfaces varying in texture, shape, and flexibility and still sustain a consistent finish across the entire piece. Powder coating is ideal for items such as:

• Motorcycle Frames, Wheels & Parts
• Automotive Frames, Wheels & Parts
• Off Road Vehicle Frames, Wheels & Parts
• Bicycle Frames & Parts
• Industrial Fabrications
• Architectural Signage
• Metal Fencing and Railings
• Retail Displays & Fixtures
• Patio Furniture
• Indoor Furniture & Kitchen Equipment
• Antique Beds, Gliders & Chairs

There are several advantages of powder coating over conventional liquid coatings:

1. Powder coatings emit zero or near zero volatile organic compounds (VOC).
2. Powder coatings can produce much thicker coatings than conventional liquid coatings without running or sagging.
3. Powder coating overspray can be recycled and thus it is possible to achieve nearly 100% use of the coating.
4. Powder coating production lines produce less hazardous waste than conventional liquid coatings.
5. Capital equipment and operating costs for a powder line are generally less than for conventional liquid lines.
6. Powder coated items generally have fewer appearance differences between horizontally coated surfaces and vertically coated surfaces than liquid coated items.
7. A wide range of specialty effects is easily accomplished which would be impossible to achieve with other coating processes.