Powder Coating
Powdercoating is a relatively new metal coating technique and was first introduced
in the early 1970's. In this process, powdered Epoxy - Polyurethane resins along with coloured pigmnents
are applied to metal products using an electro-static charge. The product is then "baked" in a high temperature oven causing the
powder to melt, flow, and then cure, forming a molecular fusion bond. The result is a surface - to - coating bonding unlike any
other.
Over recent years the application of thermosetting powdercoatings on aluminium has increased dramatically.
The wide variety of powder types now available allow the engineer or architect to specify powdercoating with confidence. Polyester thermosetting powder is the most commonly specified product because of its excellent resistance to natural weathering, a high degree of chalk resistance and colour fastness, a high level of mechanical properties and good chemical and corrosion resistance.
The colour range gives customers ample choice and if need be, special colour matches can be made.
The Process.
Components are carefully cleaned using a
mixture of mild to aggressively granular media involving a hard
sanding process to create surface "bite" assuring adhesion and consistent powder
flow.
The pre-baking cycle purges trapped moisture, oils and gasses that cause
surface contamination.
Using a high temperature
silicone media, all machined, threaded or "mating" surfaces are carefully masked
after the pre-baking cycle. Followed by an additional chemical cleaning step, completing
the preparation process.
Next the parts are coated using a special
electrostatic spray gun that is charged with 30,000 - 90,000 volts. This process applies
the powder in a smooth and even coating.
Once coated, the parts are
cured in a convection style oven at approximately 375 degrees.