Q. My company produces phone booths, and many of our parts are finished using porcelain enamel because of its durability in environmental exposure and its resistance to vandalism. Applying porcelain to some parts is impractical, however, due to the high firing temperature required, so we are looking for a replacement application. Could you recommend a liquid or powder coating that offers similar vandal-resistant properties such as hardness and scratch resistance? H.J.
A. Porcelain has already been replaced by organic coatings in many applications. One example is in the appliance industry where epoxy powder coatings are used on refrigerator and freezer liners. Porcelain also has been replaced by paint on clothes dryer drums. Although these examples involve large-volume production items, there are other, smaller applications as well. In most cases, the replacement was made with some sacrifice in the performance properties of the finished part, notably hardness and scratch resistance. These properties are greater in porcelain than in most organic coatings.
If vandal-proofing a telephone booth is dependent on these properties, there is no replacement. However, if there is room for trade-offs in the performance properties of certain parts, some organic coatings may meet your standards. I suggest you have critical parts coated by a custom coater who is able to provide a variety of coating materials. Evaluate these parts against porcelain-coated parts and make your decision on that basis.