Metallotheek is a collaboration between designer Laura van Santen, conservator Heleen van Santen and the workspace MAKE Eindhoven to explore the casting, finishing and patination of bronze, through learning by doing.
Patination is the application of a corrosive layer of chemicals on a metal. It allows you to add a wide variety of color and texture on the surface, a little like how you may treat a ceramic object with a glaze. Even though the object’s smooth casting skin shows off the skill of its maker, making it the ideal finish for many, there are more ways to add an extra layer to the surface of your work.
Patination can take place by spraying on the patina, as well as dipping, or brushing. Atmospheric conditions such as heat, pressure, and humidity also play a role in the result. The object can be sandblasted first, and polished as well.
Even though many artists may work with unique pieces, it may be useful for them and for designers to work with iterative forms. For this reason, different methods of mold making were used to find an appropriate method of repeating a shape. The ‘lost wax method’ was used, based on a mold of a 3D print; we used wax models based on a CNC milled plaster mold; and used the 3D print itself as the lost element. For the metallotheek a repeating form, albeit in varying sizes, was chosen that would show the effect of patina on a curved surface.
For these experiments we repeated a set of 9 bronze rings (90% copper, 10% tin) 9 times, to come to 81 different surface treatments. Every ring in this collection has a unique punched letter-number code that contains the combination of mold (3 types), patina solution (9 recipes), and method of application (9 techniques). Together they form the Metallotheek: a set of instructions to inspire you to get started, we invite you to experiment and add your own outcomes to this archive!
Patination is a chemical reaction on metal which forms desirable coloured products on the surface. From the endless different recipes that can be used for patination solutions, we have chosen nine for our experiments. This choice was based on the range of colours that all these patinas offer and on the safety of the user when applying the patination solutions.
The reaction of your patination solution with the bronze surface works best if your surface is clean: dust and grease-free, otherwise your results may come out patchy. Cleaning the surface can be done mechanically by blasting or sanding, or chemically by using a solvent like acetone, ethanol or white spirit, or dipping in a strong acid. As a final preparatory step before patination, rinse your surface with water and dry it using heat.
When applying the patina, make sure you are working safely- if you feel unsure about what you are doing, ask for help. Look at the material safety data sheets of the chemicals you are using to see if they can be harmful, and set up your workspace so that you can protect yourself. Keep yourself safe from chemical fumes or dusts by working in a well-ventilated space or in a fume cupboard. Use a respirator, eye protection and gloves if necessary- this holds true when mixing the patination solutions as well as when applying the patina. Do not wear gloves that can melt when working with heat.
After you have patinated your bronze surface to the hue and saturation you want it will be necessary to rinse your object to stop the chemical reaction. Rinse with hot and cold water and wash the surface with a soft brush or sponge. Be gentle when rinsing and cleaning your patinated surface, as this may be fragile and could be damaged.
Craddock, P & La-Niece, S 1993, Metal Plating and Patination: Cultural, technical and historical developments, Butterworth-Heinemann
Fishlock, D 1962, Metal Colouring, Robert Draper Ltd
Hughes, R & Rowe, M 1991, The Colouring, Bronzing and Patination of Metals, Watson-Guptill
Runfola, M 2014, Patina: 300+ Coloration Effects for Jewelers & Metalsmiths, Penguin Publishing Group
Made possible by the generous support of the Stimuleringsfonds Creatieve Industrie
Graphic Design by Jelle Koper
Photography by Jeannette Slütter
3D prints & CNC milling at fablab@EKWC by Sander Alblas