High-end wrought iron railings feature a rich variety of decorative paint finishes, mostly hand-painted with imported paints, resulting in a look that is both rustic and elegant, as well as fashionable and trendy. The most classic surface finishes include antique bronze, red bronze, antique gold bronze, black with gold trim, copper with gold trim, and white with gold trim.
To ensure good adhesion between the decorative coating (plating) and the wrought iron surface, it is essential to remove as much oxide scale, welding slag, rust, grease, dirt, and moisture as possible from the wrought iron surface before coating (plating). Otherwise, blistering, cracking, delamination, and peeling of the coating (plating) can easily occur. Pre-treatment refers to the use of mechanical, chemical, or electrochemical processes to eliminate surface defects on the wrought iron product before coating (plating).
The main methods for removing rust, oxide scale, and welding slag include manual treatment, mechanical treatment, blasting treatment, chemical treatment (pickling), electrochemical treatment, and flame treatment.
Manual processing primarily uses tools such as sandpaper, scrapers, hammers, chisels, wire brushes, and worn-out grinding wheels. Rust, scale, welding slag, dust, and other surface contaminants are removed by hand through grinding, chipping, and brushing.
Mechanical processing commonly uses tools such as pneumatic (electric) brushes, rust guns, polishing wheels, and pneumatic (electric) chisels. These tools utilize the high-frequency impact and friction of mechanical force to remove rust, scale, old paint, and other contaminants. Jet spraying uses centrifugal force, compressed air, or high-pressure water jets to propel abrasives, sand, or steel shot onto the surface of wrought iron products, impacting and abrading away scale, rust, old paint, molding sand, etc.
Chemical treatment uses specially formulated acidic solutions to soak and dissolve wrought iron products, removing scale, rust, and oil through a chemical reaction-a process known as "pickling."
For degreasing wrought iron products, organic solvents, alkaline solutions, and electrochemical methods are generally used. Various commercially available metal cleaning agents are also suitable.
