Shapeways community member Erckgillis has shared some great tips on how to patina 3D printed Silver using Liver of Sulfur, along with some patina processes for other metals.
Patinating Silver
While Liver of Sulfur is usually used to form a black or gray patina on silver, there are a number of intermediate interference colors formed, especially if a weak solution is used. These include yellow, reddish brown, purple and blue. Some people recommend adding a small amount of household ammonia to the solution claiming it intensifies the lovely blue-green-red-purple interference colors one gets when using a dilute solution and slow approach. These pretty colors are not very stable over time because they continue to react with sulfur in the air and darken. You can sometimes ‘save’ them by spraying a lacquer over them. They may be retained if the surface is properly sealed. Acrylic resin is the recommended sealer for durability and resistance to darkening in light. Some jeweler’s lacquers also work. Envirotex® works very well for this.
Using Liver of Sulfur on Silver
1.Take a piece of Liver of Sulfur, about the size of your finger nail, and dissolve it in a cup or more of warm water.
2.Heat the piece of metal to be treated and then dip in the Liver of Sulfur solution.
3.Rinse in water after each dip. While Liver of Sulfur is usually used to obtain gray and black colors on silver, there are a number of intermediate interference colors formed, especially if a weak solution is used. These include yellow, reddish brown, purple and blue. Some people recommend adding a small amount of household ammonia to the solution claiming it intensifies the lovely blue-green-red-purple interference colors one gets when using a dilute solution and slow approach. These pretty colors are not very stable over time because they continue to react with sulfur in the air and darken. You can sometimes ‘save’ them by spraying an appropriate lacquer over them. They may be retained if the surface is properly sealed. Acrylic resin is the recommended sealer for durability and resistance to darkening in light. Some jeweler’s lacquers also work. Envirotex® works very well for this.
4.The piece may be sanded lightly and polished. Raised areas will show the original color of the metal, recessed areas will remained blackened.
5.Be sure to wear gloves and protective clothing when working with Liver of Sulfur. The fumes are dangerous and it should be used with good ventilation and covered right after use. It must not be allowed to come in contact with acids as a toxic gas is then rapidly evolved.
Patinating Copper (experiments for 3D Printed Stainless Steel)
Following are techniques for Patinating Copper (Brass and Bronze are copper alloys), because of the bronze content of Shapeways 3D printed stainless steel (up to 30%) you may be able to get some success with the following techniques. If you do experiment with these processes please do share your results, we would love to see the results.
Deep Red Patina
1. Clean both sides of your metal under running water with a wet-and-dry paper towel.
2. Paste both sides with a flux paste – either borax flux, or a powder flux.
3. Heat the copper on one side until it glows orange. Turn it over and heat the other side to the same color. Then quench it in water and pickle for a few minutes.
4. The copper should be a beautiful red-purple color. If it is not, simply repeat.
5. Gently polish or lightly oil the copper with either jade oil or soft beeswax.
Blue Patina
1. Fill a small saucer with household ammonia.
2. Cover the copper salt.
3. Dampen the salt with water or vinegar.
4. Place the copper and the saucer with the ammonia with in an airtight container.
5. Allow the copper to sit for several hours to several days. Remove when the desired coloration is reached.
Green-Blue Patina
1. Fill a sealable plastic container with either sawdust or tobacco.
2. Add enough of the following solution, one part vinegar to three parts household ammonia, to just dampen your sawdust.
3. Clean your copper by annealing, pickling, and running under water. Let dry.
4. Place the copper in the sawdust mixture and cover completely. Seal the container and leave for at least one hour to several days until the desire finish is reached.
Black Patina
1. Take a piece of Liver of Sulfur, about the size of your finger nail, and dissolve it in a cup or more of warm water.
2. Heat the piece of metal to be treated and then dip in the Liver of Sulfur solution.
3. Rinse in water after each dip until you reach your final desired color.
4. The piece may be sanded lightly and polished. Raised areas will show the original color of the metal, recessed areas will remained blackened.
5. Be sure to wear gloves and protective clothing when working with Liver of Sulfur. The fumes are dangerous and it should be used with good ventilation and covered right after use. It must not be allowed to come in contact with acids as a toxic gas is then rapidly evolved.
Reference: The Jeweler’s Directory of Decorative Finishes, From Enameling and Engraving to Inlay and Granulation By Jinks McGrath