Understanding the Oxidation Process in Cast Iron Grates

Understanding the Oxidation Process in Cast Iron Grates
Cast iron grates are renowned for their durability and resistance to corrosion, starting off with a grey hue that undergoes a transformation upon exposure to water. The initial contact leads to the formation of a bright orange oxide layer, commonly referred to as "rust," which possesses a loose adherence. Over time, this initial layer washes or wears away, giving rise to a more tightly adhering oxide coating that actually serves to protect the grate from further corrosion. The end result is a distinguished, rich, chocolate brown patina reminiscent of the manhole covers found on city streets.

The Duration of the Oxidation Process

The duration of the oxidation process is influenced by the environmental conditions to which the grates are exposed. Generally, this process can last anywhere from a few months to a year. It is essential to bear in mind that the pace of transformation is accelerated in areas with higher traffic and greater exposure to various weather elements.

Longevity and Durability of Cast Iron Grates

Cast iron has stood the test of time, having been employed for centuries in the fabrication of items that require exceptional durability and resistance to corrosion. Notably, cast iron has been the material of choice for manufacturing ship anchors traditionally used by the Navy. In a raw state, our grates, like those anchors, boast a lifespan of several decades.

Alternative Options to Avoid the Orange Oxidation Phase

While we generally advocate allowing our grates to age naturally and develop their distinct patina, we understand that some individuals may prefer to bypass the bright orange oxidation phase of raw iron. For such cases, we offer an eco-friendly Baked-On-Oil Finish that utilises recycled vegetable oil. It is an aesthetic treatment that creates an aged look. As the oil wears off it will provide a smooth,
graceful transition from installation to final patina.

Alternatively we can provide a powder coating service, a metal finishing process that allows the product to be textured in almost any RAL colour or shade you require. This long-lasting, highly durable and economical finish will be more resistant against scratches, chipping, wear, and fading.

Preventing Staining of Surrounding Areas

The issue of rust staining the surrounding area can be mitigated if your grates are installed in a pre-formed drain body or our custom frames. These drain bodies and frames incorporate materials such as plastic, metallic, or polymer edges, as well as steel edges in the case of our frames. Consequently, this prevents direct contact between the iron grates and the surrounding surface. As long as the drain functions correctly, any rust particles will be efficiently channeled down the drain with the water flow.

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