Powder Coating

Written by Jeremy Horelick
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Powder coating is one method used to finish metal parts on the objects we see and use every day. Everything from the car you drive to the power tools you use exploits the benefits of powder coating, which are both aesthetic and functional. Home furnishings, appliances, boats, baby strollers, and office equipment are just a few of the items that make use of this dry finishing process.

So what exactly is powder coating? Can it be used on more than just metal? Is it environmentally safe? More so than other finishing processes? These are just a smattering of the questions people ask when it comes time to finish their parts. If you stop and think about it, it's amazing how little the average person knows about the technique used in the production of so many everyday goods!

An Introduction to Powder Coating

Powder coating is a conceptually simple idea with a host of highly sophisticated applications. At its core, the process hinges on a scientific principle most of us learned about even before our introductions to chemistry. Any kid who ever received magnetic toys came to grasp the concept that opposites attract while like charges repel. This is the starting point for a solid understanding of coating as well as other finishing methods.

Powder coaters are focused on making paint stick to the parts on which it's sprayed. The best way to accomplish this, it turns out, is to ground the surface to be coated and to charge the paint that's applied. As common sense would dictate, this helps bond the paint, which comes in powdered form, to the part hanging in the "powder booth."

Inside the Shop

While the tricks of the trade that powder coaters use vary from shop to shop, the basic techniques are the same. Coaters begin by preparing the parts in question, much the way a house painter primes wood before applying the first coat. Prep work involves smoothing out bumps in the "substrate," the material surface beneath its present coating. Sometimes the part requires "sand blasting" to restore it to health. In other instances, it needs little more than a quick sanding.

Once the part has been properly prepared, it is taken to the "application" room, which is generally a 10-, 12-, or 14-foot-long booth. The part is mounted or hung, then electrostatically sprayed with paint that has been grounded down into powder that contains pigments and other elements. This powder is then cured in an oven, which literally bakes the finish onto the part in such a way that provides a smooth and even finish that's resistant to abrasions and chipping.

The Final Steps

Once the parts have been completely sprayed, they must be allowed to dry and cool. This is largely where and when the quality of the final finish is determined, as parts that are prematurely removed may never be fully "crosslinked"; that is, their particles may not fully mesh to provide the most attractive and protective finish possible. This is a huge disservice to the customer, who may then need to refinish the item.

A lot of customers wonder whether or not it's safe to ship powder-coated parts in the mail, and the answer is absolutely, provided the coater takes the time to prepare them. While powder coating is highly effective, it does not provide an indestructible finish. No finishing technique does. That said, there's no reason why individuals in one part of the country or the world can't have their powder-coated parts sent via mail, UPS, or FedEx from another region or even continent.

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