Oxidised copper · Oxidising
Oxidising
A surface that is not applied but comes out of the metal itself. That is why it does not flake and cannot be scraped off.
Colour out of the material
Paint sits on top of metal. An oxide layer is the metal, only transformed: copper that has combined with oxygen. That is why it holds fast, has no edge against a substrate, and shows no foreign colour underneath when scratched, only copper again.
Outdoors the air takes care of this, slowly and without consultation. In the workshop we run the same process under steady conditions and stop it where the desired tone stands. Every surface passes through hands, not through a machine. Two sheets look similar but never identical, and that difference is intended.
Why this does not happen on the building
Chemical colouring agents for copper exist, and they work within their intended scope. That scope is small items indoors. On a façade or a roof surface under site conditions the result is as a rule patchy, because neither temperature nor dwell time nor the quantity applied can be controlled evenly.
Durability comes on top of that. Artificially created layers of this kind are usually not weather resistant. The natural process carries on working and lifts them off again after a while. For both reasons the German Copper Institute advises against colouring on site and points to factory-made sheets and strips instead.
The assessment of colouring on site follows the German Copper Institute information sheet i.30.
What else we do
Cutting and bending happen in house. If you want to take delivery of a finished component, you get a finished component.
What is possible in a given case depends on the component. What is binding are the details in the quotation from ZinCuTec GmbH.