< PATINATION (GREEN)
RED
A red patina can be developed on a COPPER ALLOY as a very light deposit. A light deposit allows for the partial reflection of light back to the viewers eye from the underlying metal cast. The HOT TORCH technique described here can be used to produce variable tones from a light red with a green tint (due to the alloy’s copper content), through to a deep rich red, reminiscent of a treated redwood (especially when deposited over a PENNY BRONZE ground). A strong home made PICKLED FERRIC solution of dissolved IRON FILINGS in a NITRIC ACID solution, can produce a near orange patina on selected copper alloys (note; COPPER FILINGS can also be dissoved in NITRIC ACID to produce a PICKLED CUPRIC patination compound).
1. Prepare the cast by semi-polishing (to a SATIN finish), the work’s surface. This can be done either manually (wire brass brushing etc), or mechanically (glass bead peening etc).
2. Dissolve about 1 full tea spoon FERRIC NITRATE crystals into 1/2 pt of warm water (vary according to the intensity of patina desired).
3. Pre-heat the cast gently (the applied solution should just lightly sizzle off surfaces), and apply the dissolved ferric solution using brush or spray diffuser until an even deposit develops.
4. Allow the cast to cool to touch warm, then highlight surface textures by partially rubbing back the deposit using either wire wool, a soft brass brush or a fine/worn abrasive cloth.
5. Repeat the application of a ferric nitrate solution if desired, then allow the cast to cool down again.
6. If necessary, repeat the wire wool highlighting process and apply more solution, until a desired depth of colour and overall effect is achieved.
7. Allow the cast to stand and cool, then apply a clear wax protection (hot applied wax will further darken down the patina deposit)
RED-BROWN (DARK)
1. Prepare cast as stages 1-3 for a penny bronze patina.
2. If desired, highlight the deposited GROUND PATINA, this help can add depth to subsequent applications.
3. Prepare a strong FERRIC NITRATE solution, approx’ 1 table spoon to 1/2 pt water.
4. Pre-heat the cast, and apply the FERRIC solution. Take care not to overheat the deposit.
5. Allow the cast to cool, then protect with a hot or cold wax application, according to the effect desired.
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