Machine dishwashing should be avoided with any printed product to maintain its lasting beauty. Although our product is somewhat dishwasher resistant, a lot has gone on in the industry over the past year or two. A number of the companies that produce dishwasher detergents are adding a product called citric acid. In some cases, the concentrations of this type of acid are very high, and problems have begun to surface throughout the industry. These issues are not exclusive to us, as all decorators have been working toward different strategies to combat the problem. The citric acid and alkaline in the detergents sit on the glass and ceramic, and over time, begin to attack the surfaces. This does not just affect any printing, as it slowly breaks down the glass or ceramic body’s surface. Over time, the glass surfaces will start to look pitted or foggy, but what is actually happening is that the acids and alkali are softening the surface and then an actual tiny piece of the surface breaks away. Over time the entire surface begins to look very scratched and/or cloudy. The same thing has begun to happen with the Lehr fired prints, and over time can break down the surface and begin to wash away. Ironically our E-2 printing, which is the cheaper version, is less affected by this phenomenon. However, E-2 is a baked enamel method similar to the auto body paint on your car, so it is less scratch-resistant. In commercial dishwashers, the chemicals used are different, and we rarely see this issue.
Although Lehr firing is still the more durable, we usually recommend its use in commercial settings, in domestic locations, where promotional glassware tends to be, we recommend going with the “E-2” product. These combinations appear to be the best scenarios for the current market. In some cases where it is necessary to use transfers, Lehr firing is the only option.
Again, the issues noted above are rare but do exist, so we would always encourage hand washing where possible. As a result of these recent changes in the industry, we, unfortunately, do not offer a warranty on dishwasher resistance or scratch resistance on our products.
One last note. Due to the construction of ALL stainless steel type tumblers and cups, they should always be hand washed and should not be put in the dishwasher. Prints may scratch over time as a result of use because the imprint is not a baked or fired application.