I use Liver of Sulfur gel to oxidize copper. I clean the excess off before putting it in my tumbler. I use Dawn detergent when tumbling copper. I then put only enough water in the tumbler to cover the shot and copper. The tumbler, Lortone, runs from 30 minutes to 2-3 hours. When I take the copper out, it is shiny, but it is a brown color. It also looks like it has a think "coat of plastic" over it. After tumbling, I clean the shot in clear water and lay it on a mat to dry. How can I keep the copper from getting that brown color?
The tumbled copper often comes out of the tumbler an even, medium brown color. The strength and temperature of the patina, the darkness of the patina-on-metal, how much of the LOS is removed and length of tumbling time all contribute to it's finished color. I usually tumble-polish my items first to give the metal a very high polish finish before adding a patina. Here are a few techniques to give you a different result with copper and the LOS patina.
For a black color, I super heat both the LOS solution and the metal, (heat metal by submerging in very hot water, not by torching) and dip repeatedly if necessary until a black color is achieved. Let dry, then tumble an hour or so.
For a bronzed look, same process but tumble for 6-7 hours.
For more copper highlights, remove excess LOS patina from the high areas of the jewelry. This is easier to do while the patina is still wet, then tumble 2-4 hours.
To give jewelry a beautiful finish after tumbling with the patina, I buff by hand using a jewelry polishing cloth. I prefer the Sunshine clothes by Rio Grande for copper.
Use a slightly cooler solution or quick-dip cold (room temperature) metal for a very light patina. Tumble and then buff with a Sunshine cloth.
For a satin or brushed look, use a fine scrubby pad like 0000 steel wool or a 3M scrubby to remove the excess patina. The texture of the scrubby leaves a brushed finish on the metal. You may scrub the metal after tumbling with the patina, or directly after you add the patina, but do not tumble a second time. Tumbling will remove the satin/brushed texture you've added. How fine or coarse the scrubby is creates a slightly different finish. Experiment with them to find a look you like best. Protect with a matte-finish lacquer as a shiny one will ruin the satin effect.
If left to its own devices, copper will turn brown like a penny. Bright copper and most patinas-on-copper require some sort of protective coating such as a wax or lacquer finish to preserve them.
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