Corten Weathering Process

1st February 2017

Corten™ Steel is a very popular product that can be used to make the framing of windows and doors by IQ Metal UK. Corten is a group of steel alloys that were developed to eliminate the need for painting to create a stable rustic appearance as though the metal had been exposed to the weather for several years.

The Corten activation process occurs through machining, oxidation and subsequent passivation and surface finish treatment. The machining of corten steel sections to make window and door frames is the same process when creating Secco systems in galvanised steel. A corten steel welding rod or electrodes must be used when these frames are made with weld joints.

The oxidation is the first part of the process when a brush soaked in detergent is used to coat the steel. This detergent is then dried by being wiped with a cloth. The next step is to apply a 50% solution of demineralised water and detergent by brush. This must be applied in a well-ventilated environment or outdoors at a temperature above 5°C.

Once the product has been treated, it cannot be exposed to extreme weather immediately. If the process is being done in the winter, the product shouldn’t remain outdoors during the night or when the temperature falls below 0°C. The materials must be kept indoors at night when it is forecast that temperatures will be below 0°C but can then be taken outdoors again in the morning.

After one week of the first application and when a patina of rust has formed, it is possible that another coat of demineralised water is applied with a cloth. The material can then be left to rest again in the exact same way it was left during the first week.

The products should have reached the required degree of oxidation two weeks after the second application. 50% of Gardolene D 6870 and 50% demineralised water is then applied after the oxidation treatment.

This passivating solution must be applied by using a dry cloth to remove the surface dust so that the surface becomes smooth when treated. The passivating solution is then applied by brush without leaving any drips. When this solution is completely dry, beeswax must be applied with a brush and then dried with a cloth to spread the wax evenly over the surface.

To find out more about the corten rust activation process, or our Corten Steel windows and doors, call us on 01494 772 880 or email us

Tags on this post: corten steel, weathering process

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HP6 6JQ,
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Nazeing New Road,
EN10 6SU,
United Kingdom



+44(0)1494 722 880

IQ Metal are at the forefront of bespoke metal work and steel window fabrication. Our state of the art factory and desire to create beautiful products allow us to work on some of the most prestigious architectural projects in the country. We pride ourselves on customer service so please contact us immediately if you have any queries or questions about any of our luxury steel windows and doors.