'Aurora Borealis' by Thomas Joynes
Emerald Green Bronze Patination
A very stable intense green bronze patina. Genuine Chromium Oxide is the key colouring agent in this patina, it adheres incredibly well to the bronze with the right fixative and doesn't seem affected when heated even to a high heat. As with all pigment based patinations, the surface can easily become overloaded with the pigment and with chromium it tends to create an opaque solid colour very easily.
Base Metal PB102 / sandblasted to a even 80 - 100 grit
Base Coat Chemical
1 - 2 teaspoons of Liver of sulphur ------- 1 litre of water
Apply this solution to the bronze and look for the reaction, it should be a gentle transition of colour. If the colour changes dramatically, then dilute the solution until you get a gentle transition.
Base Coat Application
Warm bronze very gently, apply weak solution of basecoat. You want the bronze to change colour gradually, continue applying solution to develop a good even colour. Rinse the surface with water and a brush, this removes some of the residue and helps to neutralise the chemical reaction. Heat the bronze until a fine dusty film appears on the surface, remove this with 120 grit scotch brite pad or other appropriate soft abrasive.
1st Colouring Coat chemical solution
Water ----- 250 ml
Medium Copper Nitrate solution ------ 2 teaspoons
Chroumium Oxide ------ 1/2 teaspoon
Additional Fixative ----- Weak sodium silicate solution
1st Colourcoat Application
Heat the bronze evenly, the solution should just sizzle and evaporate away as you apply it with a natural haired paint brush. Take small amounts of solution into brush at each application, as the brush warms up it natural sucks the solution up into the brush. Use a small brush to stir the solution keeping the oxide in suspension, chromium quickly settles out. The oxide that forms on the surface of the bronze should develop into a blue and intense green ring or patterning. The method we have most success when establishing an intense colour, is to develop the colour gradually in thin layers, its very easy to overload areas and end up with a patchy opaque patina.
Sculpt Nouveau Smart Coat - 1K Polymer Sealant
When the bronze is at room temperature, we use soft cloth or brush to apply 3 coats, letting them fully dry between applications.
To add additional colour to highlight areas, we mix a small amount of pigment with a small amount of sealant and use a sponge or brush to add this mixture.
To create shadows or to darken areas we use a graphite wax, this is thinned down with a clear wax to create a translucent paste. This is applied both under final wax layers or over the final wax layers.
Final Wax layers
We use renassiance wax for the final waxing. Its applied with a soft brush in a very thin layer, left for 10 mins and buffed to a hard finish. We add three or four layers, with the final layer buffed to the final finish.