dragonfly railing drawingSculptural Art Railings :
Applying Verde Patina

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finished cattail with Verde patina on copper

"Adding color to metalwork using natural oxides from various metals can make the difference between an exquisitely crafted piece and a cheap wanna be!"

Have you ever wondered why different metals change colors when exposed to the atmosphere? Why is it that brass and copper turn green when exposed to ocean air? Or why is it that steel turns brown? Well, the reason metals change color is because they desire to return to their natural state.

Steel rusts because the iron in it will go back to iron oxide when it comes into contact with water and air. Copper and brass, which is a copper alloy, also want to return to a natural copper oxide. The oxide can be anywhere from a dark brown/black to green and blue, and is dependent on other elements such as salts and acids.

There are many recipes for making patinas and just as many ways for the application of the patina. But one thing is for sure. You must always take steps to clean all grease and loose oxides from the metal you are going to patina!

I use a 1:1 solution of standard super market grade ammonia to soak and clean the copper cattails I have made. These pieces have soaked for several hours to allow for easy removal of the flux which remained from the soldering process.

After scrubbing the pieces vigorously, the cattails are rinsed with water prior to applying the black patina.

cleaning is crucial to good patination

applying black undercoat patina to copper

Since I want to have a high contrast mottled patina effect on my cattails, I apply a premix commercial chemical patina which turns the copper black. By diluting the mixture with water, I can get varying degrees of brown to black.

Commercial grade chemical patinas will do the same thing that nature does over time except that these chemicals are concentrated and will react faster with the metal to create the proper colored oxide patina.

When using chemicals for patinas, be sure to read the safety sheets that come with the product. Many of these chemicals are some sort of acid and will burn your skin if contacted. You've probably already noticed that I am not wearing gloves when I really should be. But because these are but a few pieces and I am applying with a brush or spray, I just made very sure that I did not contact any part of the cattail with my bare hands.

spraying Verde patina for contrast

Once the black patina had been applied and thoroughly washed to remove the previous chemicals, it was time to use a sprayer to apply the Verde patina (green). The cattails were left to dry in the sun so that I had a good surface for the spray mist to adhere to.

If you apply this patina to a wet surface, you will not get the mottled effect which occurs naturally on copper. That's the main reason for using a spray application rather than a brush.

I squirt just a little mist on the surface until I see little droplets forming and adhering. If I squirt too much, I will get unsightly runs. So a little squirt and then I wait for it to dry. Then I return and squirt a little more, and wait to dry. This process is repeated until I get the effect I want.

Once complete, the cattails are left overnight and then rinsed lightly the next morning. This will not only remove any excess chemical, but will also show if there are places that didn't take because of oils, or too much chemical patina. Yes! Too much chemical will make an oxide that simply falls off and leaves a light copper color below!

So the best way to learn about what kinds of colors you can achieve with various metals, is to practice on scrap pieces and use various methods of application. Over time you will find the right chemical and applicator to give you exquisite colors that add uniqueness to your artwork.

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