Galvanized steel, aluminium, and stainless steel are widely used across Kenya for warehouse roofing, solar support frameworks, communication towers, light poles, and industrial ductwork. While zinc hot-dip galvanizing protects raw iron against rust, galvanized metal inevitably forms white rust (zinc hydroxide) when exposed to moisture and coastal salt air. Moreover, standard industrial paints often peel cleanly off galvanized surfaces within a few months of application. Achieving long-term corrosion protection requires a specialized zinc phosphate primer in Kenya engineered for smooth non-ferrous metals.
Why Paint Fails on Galvanized Steel: The Adhesion Dilemma
Hot-dip galvanized steel presents two major challenges for protective coatings:
Ultra-Smooth Surface Profile: Unlike flame-cut or blast-cleaned raw steel, newly galvanized steel has a glassy, non-porous zinc crystalline surface that prevents standard paints from getting a mechanical grip.
Zinc Soap Formation (Saponification): When traditional alkyd or oil-based paints are applied directly over zinc, the fatty acid molecules in the alkyd resin react chemically with zinc ions in the presence of moisture. This chemical reaction creates zinc soaps at the interface—a greasy, powdery layer that destroys adhesion and causes whole sheets of paint to blister and peel away.
To coat non-ferrous metals successfully, you must avoid alkyds entirely and specify an epoxy primer engineered with specialized adhesion promoters.
Hempadur 15553: Purpose-Engineered Adhesion & Protection
Clin Corp provides Hempadur 15553, a two-component epoxy paint engineered specifically for substrates where abrasive surface blasting is impractical or prohibited.
Formulated with active zinc phosphate inhibitors, Hempadur 15553 cures into an impact-resistant, flexible coating that forms strong chemical and physical bonds with smooth metallic substrates.
Key Engineering Features of Hempadur 15553:
Exceptional Adhesion to Smooth Non-Ferrous Metals: Bonds securely to hot-dipped galvanized steel, aluminium sheets, stainless steel framing, and zinc metallized surfaces without requiring heavy sweep blasting.
Active Zinc Phosphate Inhibition: Provides chemical passivation at micro-scratches, sealing the substrate against moisture penetration and stopping filiform corrosion.
Low-Temperature Curing: Cures reliably down to −10∘C/14∘F-10^\circ\text{C} / 14^\circ\text{F}−10∘C/14∘F, ensuring dependable application throughout high-altitude or cold-season installations across East Africa.
Abrasion and Impact Resistance: Remains flexible after curing, absorbing substrate deflection, wind loading, and physical impacts without cracking or chipping.
Best-Practice Application Steps for Galvanized Steel
To maximize the service life of a protective system on galvanized steel in Kenya, follow this standard specification:
Degreasing & Cleaning: Wash the surface with clean water and industrial detergents to remove dirt, grease, and zinc salts.
Light Sweep Blasting / Chemical Etching: Where feasible, perform a light sweep blast with fine non-metallic abrasive (e.g., garnet) at low nozzle pressure to profile the zinc without stripping the underlying galvanizing layer.
Apply Hempadur 15553: Spray or roll an even coat of Hempadur 15553 at the recommended dry film thickness to establish a tenacious primer coat.
Apply Intermediate and Topcoat: Finish with a compatible high-solids epoxy intermediate coat (such as Hempadur Mastic 45881) and an aliphatic polyurethane topcoat (Hempathane 55210) for full UV and atmospheric defense.
Protect Non-Ferrous Capital Assets with Clin Corp
Applying the wrong paint to galvanized or aluminium structures leads to costly surface scraping and repainting. Clin Corp, the authorized Hempel distributor in Kenya, stocks certified epoxy primers designed for challenging metallic substrates, backed by full technical documentation and local product availability.
