Mensa Corten U-Plinth

Made from Corten Steel, the Mensa plinth will slowly, over the course of about 9 months, change from a blueish steel colour to a rich, deep burnt orange colour. This cures the steel and prevents it from further corrosion ensuring no loss of thickness in the metal and stops it flaking.

Corten Steel, also known as weathering steel, is renowned for its incredible strength. It starts out as a blue steel but during the weathering process, develops a protective oxidisation layer with a striking rust appearance. This creates a warm rich aesthetic that is not usually associated with metal.

Step-by-Step Corten Steel Weathering Guide

• Stage 1 – Freshly manufactured Corten Steel. At this stage the dark oily residue coats the Corten Steel.
• Stage 2 – The oily residue is beginning to break down, as the Corten Steel begins to weather.
• Stage 3 & 4 – The “Run-Off” stage – This can take around 3 to 9 months depending on weather and positioning.
• Stage 5 & 6 – The final stages of the weathering process. Some “Run-Off” may still occur as the Corten Steels patina develops to a striking, more consistent appearance.

Corten Steel Run Off

During the weathering process, Corten Steel produces carbon run off or staining to adjacent materials such as stone or concrete. To reduce this possible staining, we recommend raising the product up off the ground by using a suitable stand, blocks of wood, slabs and such like; this will prevent any direct contact with the flooring material. After the initial reactive period, Corten Steel will cure and self-seal with little to no carbon run off. The weathering process of Corten Steel is integral to this product and as such we will not accept any responsibility for damage caused to surrounding materials as a result of carbon run off. Please ensure you do not place your product on any surface that may be damaged during the weathering process.

Corten can be easily cleaned using water and a soft brush. it can be sealed using a metal specific varnish, please note this will make the steel appear ‘wet’ or darker for the rest of the item’s life.

If Corten Steel is scratched or the weathered surface is damaged, it will re-weather (heal) to form a new skin to protect itself, making the damaged area nearly undisguisable.

The Initial Weathering Process
Upon receiving your Corten Steel garden feature, it will likely appear unweathered with a dark, oily residue. This is the first stage of the weathering process, which protects the steel during transportation and initial setup. 

Place the Corten garden feature outdoors in an open area where it can be exposed to the elements. The weathering process, where the steel forms a protective rust layer, typically takes between 3 to 9 months, depending on weather conditions. 

During the weathering period, avoid placing the feature on or near porous surfaces like stone or concrete to prevent staining from rust runoff.

Guidance on Sealing and Maintenance
Once the desired rust patina has developed, sealing the surface with paint conditioning and rust inhibitor oil is recommended to stabilise the rust layer and minimise further runoff. 

Our sealing oil recommendation: Owatrol Oil

This product penetrates through the rust to the sound metal below, isolating and protecting it from additional corrosion. You can apply Owatrol Oil using a brush or sprayer and allow it to dry for 12 hours, with a full cure taking up to 48 hours, depending on environmental conditions. This treatment not only enhances the durability of your Corten Steel garden feature but also maintains the integrity of its rustic appearance.

By following these simple steps, your Corten garden feature will achieve a beautifully weathered look while being well-protected for years of enjoyment in your garden.