Powder Coating Process
The powder coating process consists of the following stages:
Pretreatment
Proper surface pretreatment before applying primers or powder coatings is essential.
Surfaces must be clean, dry and free of oil or contaminants.
The cleaning method depends on the type of metal and type of soils present.
A typical cleaning procedure for ferrous metals would be a solvent clean and sandblast
resulting in good mechanical bonding of the coating.
Sand Blasting
Before we can powder coat, the surface needs to be cleaned. The technique usually used is
chemical stripping and/or sand blasting. Sand blasting is used to clean surfaces and prepare
them for a new finish. It is also an effective method for removing rust, oxidation and old paint.
Old gates, railings, metal parts or any other metal piece can be stripped clean using this method.
Sand blasting is carried out in a special booth and the worker is required to wear safety gear.
An abrasive mixture of ganett silica & plastic is forced through the nozzle of a specialized
blasting machine at high pressure to blast away paint and rust. The abrasive material is
propelled by compressed air.
Powder Coating
Powder Coating delivers a durable, scratch-resistant, chemical-resistant and UV-resistant finish,
making it an attractive option for manufacturers everywhere. The faster throughput and minimal
curing times make it one of the most affordable finishing options.
Powder coating is an advanced method of applying a decorative, protective finish to a wide range
of materials and products. The powder used for the process is a mixture of finely ground particles
of pigment and resin, which is sprayed onto a surface to be coated.
The electrostatically charged powder particles adhere to the grounded surfaces until heated and
fused into a superior coating in a curing oven. The result is a uniform, durable, attractive finish.
The powder has the consistency of flour and is applied electrostatically. "Charging" the powder with
10-thousand volts and spraying the item, which is hung on metal hooks, do this. Next, the item enters
an oven and is cured at approximate temperatures from 300° to 400°f.
Any materials that cannot withstand this time and temperature exposure must be removed before coating.
This would include foam insulation, rubber, plastic, bushings, paper or gaskets. Powder coating offers
an economical, long-lasting and color-durable quality finish. In other words, it looks like paint,
but acts like armor. Powder-coated surfaces are more resistant to chipping, scratching, fading,
corrosion and wearing, and colors stay bright and vibrant longer. There are even surface options
ranging from smooth to texture and matte finishes. Powder coating is the fastest-growing finishing
technology in North America.
Powder Coating Is An Environmentally Friendly Process
While liquid finishes contain volatile organic compounds (VOC's) that can pollute the air, powder
coatings require no solvents and release only negligible amounts of VOC's into the atmosphere.
Because emissions are virtually non-existent, there is no need for costly pollution control equipment.
In addition, most powder coating over spray that does not adhere to the part can be retrieved and reused,
eliminating waste commonly found in liquid finishing processes.