At our outdoor bench factory, every steel leg passes through a controlled hot dip galvanizing line. We do not rely on paint alone. The goal is to create a metallurgically bonded zinc coating that shields the steel from moisture, oxygen, salt, and other outdoor corrosives. The process begins with weld preparation. We inspect each leg, remove welding spatter, grind sharp edges, and drill drainage and vent holes where needed. These small details allow zinc to flow inside and prevent trapped air or moisture, especially in tubular legs.
Next, the legs go through pre-treatment. They are degreased in an alkaline bath to remove oils and shop dirt, rinsed, then pickled in acid to remove mill scale and rust. After another rinse, they enter a flux bath, which keeps the steel surface active and helps molten zinc bond evenly. The legs are dried thoroughly before entering the zinc kettle; any moisture would cause splashing and weak spots.
The galvanizing itself takes place in a molten zinc bath around 445-455°C. Immersion time is adjusted according to steel thickness and leg design. During immersion, zinc reacts with iron to form a series of zinc-iron alloy layers, topped by a pure zinc layer. This coating does not just sit on the surface. It becomes part of the steel, so it resists chipping and abrasion. After removal, the legs are vibrated or centrifuged to remove excess zinc, giving a clean, uniform finish without clogging threads or mounting holes.
Cooling and passivation follow. The legs are cooled in air or water, then optionally treated with a passivation solution to reduce white rust during storage and shipping. We measure coating thickness with a magnetic gauge and check adhesion, appearance, and coverage. For outdoor bench legs, we typically target a zinc coating that meets ISO 1461 or ASTM A123 requirements, with extra attention to welded joints and cut ends where corrosion often starts.
If a leg must be cut or drilled after galvanizing, we repair the exposed area with a zinc-rich touch-up coating. During final assembly, we use stainless steel or galvanized fasteners and avoid direct contact between dissimilar metals that could accelerate corrosion. Every batch is inspected before packing, and legs are separated with protective materials to prevent abrasion in transit.
This complete galvanization process is why our outdoor bench legs can handle rain, coastal air, and seasonal temperature changes without rusting prematurely. The combination of proper design, hot dip galvanizing, quality control, and careful handling gives the bench a long, low-maintenance outdoor life.
