Exterior Coatings Designed for Expanding and Contracting SurfacesPenncoat Inc
Expanding and contracting metal surfaces require flexible industrial coatings.
Dust collectors are important pieces of equipment for facilities. However, their outdoor locations make them vulnerable to fluctuating temperatures and inclement weather. So when specifying an industrial coating system, it’s important to recognize these environmental challenges that compromise the integrity of both the substrate and coating.
Varying temperatures can cause sheet metal to expand and contract, creating an unstable surface. Additionally, the ultra violet rays and moisture can cause discoloration and delamination. And although hard coatings like epoxies and alkyds are popular, they are likely to chip and crack due to the stress caused by the flexible surface. Additionally, UV rays can accelerate their color distortion.
In these exterior situations, an elastomeric coating serves as a great solution. It offers elongation and tensile strength to prevent failure on flexible surfaces. And it’s acrylic properties help maintain its color stability in the exterior environments. In our recent project, this elastomeric proved to an excellent application.
But before any coatings can be applied, the surface preparation needs to be addressed. We consulted with the owner, to verify that there wasn’t any sensitive equipment or property that could be damaged by the pressure washer. And after receiving the approval, we pressure washed the substrate to remove the dirt and debris.
After the surface was adequately prepared, we were still left with corroded areas. Corrosion can often bleed through the top coat, depending on the product. So to prevent this bleed through, we applied a rust inhibitive primer. This primer will lock in the corrosion, preventing it from bleeding through the elastomeric coating.
Once the preparation is completed, adequate masking and protection was applied to the surrounding equipment and property to prevent paint over spray. Once the containment was set up, 2 coats of elastomeric coatings were applied with a sprayer. This paint needs to have a dry-film-thickness of about 25mils. However, it is only about 50% solids, meaning that half of the wet material will dissipate during curing. So it is important that the applicator applies 25mils of wet film thickness in each coat, to achieve the 25mils of dry film thickness after 2 coats.
Once the project concluded, all the sheet metal was coated with the appropriate amount of elastomeric coatings. This will ensure that the coating remains adhered to the dust collector, without being compromised due to the stress from the flexable surface. And although the dust collector remains outdoors, the color retentive properties from the elastomeric coating will help the paint maintain its color, without the ambering effects that typically come from epoxy or alkyd coatings.