We oftem get asked how long will Powder Coated Signs last in the outside elements that are heavy in Rain, Snow, Salt, High UV exposure. Well the answer, as always, it depends. Here are two examples with some detail of how they were prepared and what they were exposed to.
This sign was coated with an epoxy primer and a color black topcoat. The sign is now seeing its 5th winter in Michigan. It sits at the end of the driveway, at the street, and is always getting the spray from the Salt Truck and Plow Truck in the Winter, along with all the standard rain and sun. Still holding its color and gloss but starting to show corrosion streaks eminating from the area where the letters are cut. This is the common area to see issues first as the corner between the flat surface and the inside of the letter receives the thinnest coating. Overall though pretty good for 5 years in a reasonably tough environment. Probably another year or two of life before it would need to be recoated or replaced.
This sign is also on its 5th Michigan Winter. Same Process, Epoxy Primer and Blue Topcoat. It is placed close to the house and therefore does not see any of the salt environment from the Snow Removal. Otherwise all the same sun and rain as the first sign. It is not showing any failure. We would expect this sign to still look great for another 3-5 years.
Our standard coating process for exterior projects utilizes an Epoxy Primer and a Double Coat of the Color like these signs received. This is a cost effective and well performing solution as these demonstrate, for a pretty cost sensitive ornamental item for a personal residence. In some cases where we expect a very severe environment or budget allows, we add additional steps of a Phosphate Base Metal Treatment, followed by a Zinc based primer, then the double top (color) coat and in some cases an additional clear coat. Each step requires additional time and material so there is a tier of costs to produce them. We hear situations where these are presented to the customer to justify a orice and then not performed to save money. How would the customer know? The difference won't show for several years. In our shop when a customer pays for the additional steps, we just shoot a picture of the project at each step in the process and review with them. Only takes a few seconds and we both have confidence that we did what we promised and what they paid for.
Many people want to say that Powder Coat is the panacea of coatings and will last for ever or 1000's of hours in laboratory salt environments. It can with a lot of "IF's". It does very well compared to many other coating alternatives at much higher prices but Mother nature always wins and we want our customers to have an honest understanding when they purchase what to expect.