Powder coating is a type of coating that 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 important to understand a few basics about powder coating so you can make the right choices on your next Point of Purchase display:
- Material Choices- In many cases powder coating is sprayed on by a human operator using a spray gun. An alternative to a standard epoxy finish is a PU (polyurethane finish) which is applied by dipping the metal in a vat of PU liquid. A PU finish is similar to a rubber coating like the shelves you might find in your refrigerator.
- Smooth vs. Textured- Most retail fixtures have smooth finishes, but textured finishes are also available. Textured finishes are created by mixing a granular material similar to sand into the powder before applying.
- Glossy vs. Matte- Both glossy and matte finishes are available so it is important to specify the finish you want.
- Clear Coat- Clear coating metal is also an option, but in many cases it is more difficult to execute well. It is very important with clear coating that the metal be chemically treated to remove all rust and other impurities, otherwise clear coated metal will start to show visible rust over time. (Note that an important step before any type of powder coating is submerging the metal parts into a chemical tank to remove rust.)
- Chrome Finish- Many fixtures in the POP display industry have chrome finishes. Chrome plating tends to be more expensive in China due to stricter environmental regulations and the additional labor required for a high quality finish. Chrome plating on large surfaces tends to be significantly more challenging. The key to a good chrome finish on large surfaces is a good polishing job prior to the chrome plating process. All imperfections in the surface need to be removed during the polishing process or the finish may have lines, pitting, and other visible imperfections. An example of pitting is shown in the upper left corner of the chrome plated piece below.
- Color Choices- The most common color choices in the retail display industry are silver, black, and white. Custom powder coating colors are available often at no additional charge, but there may be minimums. PMS color matches are available, which creates a world of possibilities in creating unique fixtures.
Paying attention to powder coating quality can help to ensure that your display meets your expectations. A few tips to consider:
- Examine the finish carefully to ensure full and even coverage of the powder coating finish. Powder coating is often applied manually so it is entirely possible that parts of the metal get missed. Exposed metal can rust very quickly so it is important to ensure full coverage.
- Check for finish durability. Poor powder coating jobs can result in the powder coating flaking off easily or bubbling. This can also happen if the powder coating factory fails to chemically treat the metal or does a poor job of it prior to powder coating.
- If possible find out where the powder is coming from. Make sure it is from a reputable source. Some suppliers of powder coating dilute the powder to save money. The result is a poor finish.
- Make sure when metal parts are packed together in the same box, they are either wrapped in plastic or some type of packing material. Left unprotected, two metal parts can rub together during shipping which can result in scratching or chipping of the finish.
- Don’t try to powder coat screws and nuts. We have learned that trying to powder coat screws to match the color of a display only works in the short term. Inevitably, the powder coating chips off and makes the hardware look cheap.
Powder coating can even be applied to MDF to create some interesting and durable finishes. There are not many suppliers who powder coat on MDF and it tends to be fairly expensive, but it can make a nice finish. We used powder coated MDF on this display that we made for Zodiac Pool Systems.