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TIPS FOR PATINAS ON STEEL
TIPS FOR PATINAS ON STEEL
"Processes, methods, and apparatus presented herein have not been tested or verified by ArtMetal in any way. Anyone using any of this information is doing so at their own risk."
The patinas discussed here are copper sulfate solution, Black Topaz, and Rusty Red. I mix my own copper sulfate solution by mixing copper sulfate crystals with water, a little at a time, until the water will no longer dissolve the copper sulfate. Copper sulfate is available at Southern States stores.
Black Topaz and Rusty Red are sold by Sur-Fin Chemical Corporation. Sur-Fin will send you a finish kit including seven six ounce bottles of their finishes for $50 (they also sell patinas for other metals). Larger sizes from one to fifty-gallons are available.
These finishes result in a variety of effects depending on strength of the solution, reaction time, relative humidity, temperature, surface texture, and type of top coating.
The Rusty Red and copper sulfate solution create similar effects. The Rusty red seems to be a bit more red and the copper sulfate is a bit more orange. I prefer the copper sulfate solution. It is more beautiful and less expensive than the Rusty Red.
The surface to be finished must be completely clean. Remove all scale by sandblasting or wire brushing. Different surface textures will create different results. Sand blasted surfaces tend to be more dull and require a shorter reaction time. Wire brushed surfaces will be shinier, but require a longer reaction time. I sandblast first to remove the scale and then wire brush to create a shiny surface.
Remove all grease, oil, and, dirt with mineral spirits. Surface must be white glove clean for best results. Different concentrations of the finish solutions give different results. Sur-Fin recommends diluting the Black Topaz 1:10 with water. I have used the Black Topaz at 1:5 with a very brown /black result. Different reaction times give different results. I usually leave the solutions on for just a few minutes. The Black Topaz ranges from a jet black with a short reaction time to bluish, greenish, black with longer reaction times to brown/black with very long reaction times. The Rusty Red and copper sulfate solutions range from a light copper plating effect to light rust to a dark crusty rust depending upon reaction time.
Some interesting effects can be created by using two or more finishes on the same piece. The Rusty Red and copper sulfate solution will work on top of the Black Topaz finish. The Black Topaz does not seem to work on top of the others. I often begin with the Black Topaz and drizzle, drip, or brush a pattern on specific areas of the surface, leaving other areas bare. I then allow the Black Topaz solution to react until it is dry.
Then I come back and coat the entire piece with the Black Topaz solution and quickly rinse the piece in water to stop the reaction. The areas treated first will have a different tone than the areas treated later. I then come back over the piece with the Rusty Red and/or copper sulfate solution and brush, drip , drop or drizzle it in specific areas to create coppery or rusty highlights. The entire piece is then thoroughly rinsed with water to stop the reaction.
Once you have stopped the reaction by rinsing with water, allow the piece to air dry or speed up the process by heating it with a torch. At this point the piece is not very pretty. You will not know what the piece will ultimately look like until you apply a top coat.
I usually heat the piece with a torch until it is barely hot and then apply wax with a lint free cloth. I have heard that linseed oil also works well. At this point the patina will reveal itself in its final state. By applying more wax and rubbing I can usually remove some of the more rusty spots revealing coppery areas. Additional coatings of wax will create a shinier finish with more depth.
These chemicals are poisonous. They will irritate your skin and eyes. Wear rubber gloves, goggles, protective clothing, and a respirator. Read the labels on these products and dispose of properly. Keep them away from your kids.
It takes time and experimentation to get good results with these chemicals.
Your finishes are likely to look different from mine due to the many variables involved. I am continually experimenting with different finishes on metals, steel in particular. I would like to compile a data base of information on this subject to share with other metalworkers.
If you have information that you would like to share please let us know.
ADDRESSES FOR PRE-MIXED PATINAS:
CHEMICALS FOR MIXING PATINAS:
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ArtMetal Editor/Curator:Enrique Vega