Q: Is there a powder coating material that is resistant to or impervious to 15% sodium hypochlorite (bleach)? We’re coating pumps that are, for the most part, used indoors in chemical, food, and sewage or water treatment plants. We handle chemicals like bleach, magnesium hydroxide, acids, caustic, lime slurries, clay slurries, printing ink, sodium silicate solutions, etc. These chemicals often get splashed on the exterior as well.
To date, the only feedback I’ve had regarding these chemicals is that bleach has affected the interior of the pump when a hose fails. When the hose fails (which will inevitably happen after several million cycles), the chemical being pumped sits within the pump barrel until the maintenance crew discovers the problem.
We’re currently using a polyester coating electrostatically applied and baked. Since it isn’t our shop, I’d like to recommend a product that can be used without much disturbance to the existing process. We’re only a very small portion of the paint shop’s work.
We’ve been painting our pumps black. Our current finish is a glossy look, which I like. We’ve paid an industrial design firm to make the product look good, and the gloss adds to the panache. We apply two (2) coats.
A: You should consider using an epoxy. It’s the best way to resist the chemicals that your pumps will encounter. The gloss polyester doesn’t have the guts to hold up to most strong chemicals.
Epoxies have been used successfully for years in extreme durability applications such as gas and oil pipelines, brake parts, and laboratory furniture. Epoxies are routinely formulated in a high-gloss finish.
If exterior performance is critical, you may want to consider using epoxy for internal components and polyester for external ones. Sounds like a potentially overly complicated process, however.