Cor-Ten Steel products seasoning instructions

Cor-Ten Steel products seasoning instructions

Thank you for choosing a GrillSymbol or Petteri Wiimaa Cor-Ten product. If your item does not initially match the appearance shown in the pictures, please follow these guidelines to process and achieve the desired finish.

Understanding Weathering Steel

Weathering steels, such as Cor-Ten and S355JOWP, are high-strength structural steels with superior resistance to weathering. Their chemical composition allows them to develop a protective patina layer over time, which enhances durability and provides an aesthetically pleasing rust-like finish. This natural patina not only protects the steel from further corrosion but also adds a distinctive character. Unlike conventional steel, weathering steel is environmentally friendly due to its longevity and can be left outdoors throughout the year.

Care Instructions

1. Unpacking:

   • Upon receipt, unpack your product immediately to prevent moisture accumulation within the packaging, which can lead to uneven rusting.

2. Surface Seasoning:

   • Normal Process: Place your Cor-Ten steel product outdoors. Exposure to rain and moisture will initiate the rusting process, developing a protective patina. Pre-cleaned with a solvent, the surface is ready for rust formation. Initial rusting should appear within 1-3 weeks, with complete patina development taking approximately 3-5 months, depending on local weather conditions. To expedite this, you may occasionally spray the product with water.
   • Accelerated Process (at your own risk): Apply a salt solution to the metal surfaces 5-6 times. Prepare the solution with 1 teaspoon of salt per litre of warm water. After spraying, ensure the product is not kept indoors or under cover but is repeatedly rinsed by rain or manual sprinkling. No additional treatment is required.

3. Handling Staining:

   • During the initial rust formation period (about one year), the product may emit rust, which can stain surfaces beneath it, such as wooden decks or stone. To reduce staining, elevate the product using M6-M10 bolt heads (6-10 mm high), creating an air gap between the product and the surface. After one year, the rust layer stabilises, and staining should be minimal. Note that the manufacturer is not liable for damage or staining resulting from the product’s natural material properties.

4. Indoor Use and Rusting Prevention:

   • For indoor use or to slow the rusting process, consider applying Owatrol 732SK rust oil. This product will darken the rusty surface slightly and provide a subtle shine.

5. Flowerpot and Planter Box Care:

   • For flowerpots and planter boxes, place a layer of light gravel (10-20 mm in diameter) about 10 cm thick at the bottom to ensure proper drainage. Avoid placing pots directly on soil or grass, as excessive moisture can lead to uneven rusting.

By following these guidelines, you can ensure that your Grillsymbol or Petteri Wiimaa product achieves the desired appearance and maintains its performance over time.