Steelpaint GmbH confirmed the successful application and long-term performance of its one-component coating system, Stelpant PU Combination 500, on fibre-reinforced plastic (FRP) and glass flake structures.

The project involved the external refurbishment of nine vertical FRP tanks at a processing facility in Ban Chang, Thailand. The tanks, exposed to sunlight, humidity and airborne chemical vapors, were coated in November 2021. A 1,250 m² surface was primed and topcoated with Stelpant PU Combination 500, each layer applied at 100 µm dry film thickness (DFT) by roller.

A follow-up test in March 2025 used the same coating system on the 840 m² roof of a wastewater tank, applying a 130 µm base coat of Combination 500 with a polyurethane topcoat.

Steelpaint’s chief technical supervisor, Dmitry Gromilin, said the tanks had shown surface degradation due to prolonged UV exposure in an aggressive industrial environment. The one-component system allowed for application with minimal surface preparation, bonding effectively to the porous glass flake matrix and restoring surface integrity.

Stelpant PU Combination 500 is a high-build, moisture-curing polyurethane coating containing micaceous iron oxide, designed for use on steel, galvanized metal, concrete and composite materials. It offers DFT recommendations of 100–200 µm per coat and is resistant to water, UV degradation, and industrial atmosphere.

“This marks the first time we’ve applied the coating directly to a glass flake structure in that kind of challenging environment,” said Steelpaint Director Frank Müller. After three-and-a-half years, the tanks remain in “excellent condition.”

The product complies with ISO 12944 C5 requirements and can be paired with Stelpant PU Zinc primer or UV-stable topcoats for enhanced durability. Additional projects using the system on galvanized roofs and concrete surfaces are ongoing. Steelpaint plans to release further technical guidance to support expanded use.