Patination is a process that occurs naturally when metal is exposed to air and humidity over time A thin, oxide layer develops, producing a green or brown color (on copper). However, the process of patination using chemicals or heat to purposefully induce the formation of patina has been used by artisans for thousands of years. This is done not only to create a distinct aesthetic appeal, but to protect the metal from rust and contribute to its longevity.
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| Sculpt Nouveau offers a full range of patina and metal finishing products. |
The process used here is a combination of dye-oxide and heat. Dye-oxides are colorants that function as oxides, making them versatile in their application in that they can be blended or layered to achieve any color. These patinas are UV safe, non-reactive, and do not contain acids, which make them safe for handling and more than suitable for outdoor applications. To yield the best results, thorough surface preparation and use of the “right” products is paramount. Follow along for a more detailed procedure.
SURFACE PREP.
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| Scuff up the copper using 400-grit sandpaper. Remove any excess debris with a metal cleaner and degreaser. |
The sucess of your end result is only as good as the initial preparation. So, with that adage in mind, I began by sanding the surface of the copper to get a uniform appearance as well as remove any factory coatings. This was followed by a metal cleaner and degreaser, which removes contaminants and ensures proper coating adhesion.
BRING ON THE HEAT.
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| Heat the copper to 180-200°F using a propane torch. To ensure temperature accuracy, I used an infrared thermometer. |
Dyeoxide adheres best when the metal is warmed. This is due to the increased surface tension and adhesion energy when subjected to higher temperatures. As the surface temperature rises, the oxide layer becomes more viscous and adherent. Here, a propane torch was used; however, a heat gun is also sufficient. Once the copper reaches the recommended temperature range, the dye-oxide can be applied. If using multiple colors, continue to flash the surface in between coats to maintain proper heat and dye adhesion.
LAYERING COLORS.
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| Dye-oxide patinas are a cross between solvent based dyes and a patina. The colors are all transparent and can be blended and layered together to achieve a variety of custom colors. Above, green-blue and red are used to imitate the seasonal transformation of the ginkgo leaf. |
As mentioned earlier, dyeoxides can be layered and blended. The best way to do this is by diluting select colors with distilled water. This allows base colors to emerge through additional layers. Furthermore, experimenting with the water to dye ratios is a great way to achieve desired visual results.
Depth and dimension can be further added during the layering process by using the texture of different materials (sponge, brush, cloth) as a blotting tool. These alternative materials function as applicators, but can also aid in blending color as well as creating texture or a pattern.
LOC & SEAL.
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| ColorLoc is an air-drying lacquer used to seal in the patina. Once dried, an additional top coat of Ever Clear was applied to further protect the metal for life outside. |
Once you’ve completed the patination process, it’s important to lock in or seal the color(s) created. For this process I used Colorloc, seen in Fig. 5. This is a clear, air-drying lacquer that has great adhesion to various types of metals. The purpose of this product is to protect the colors formed by torch, flame, or heat treatment on a variety of metals.
For further preservation of the patina, a two-part clear, low VOC polyurethane was applied over the Colorloc. This additional clear coat (Ever Clear) provides underfilm tarnish protection, as well as exceptional resistance to UV light, salt-air environments, and most chemicals. And since our gate will live outdoors, the added insurance was a welcomed addition. Overall, Sculpt Nouveau makes the patination process a breeze — even for a novice.
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| The copper leaves are arranged in a fan motif to further illuminate the depth and complexity of the patination process. |
