How to Oxidize Brass and Copper to That Gorgeous Brown Color
There are actually several ways to get that gorgeous brown patina on your copper or brass. You can use chemicals, or more eco-friendly methods.
Some chemicals can be caustic and must be used with care. I use clear household ammonia, which works on copper and brass. Then of course there are the more common chemicals such as Liver of Sulfur, Black Max (which contains hydrochloric acid and tellurium), and antiquing solutions that contain iron nitrate.
The Hard-Boiled-Egg Method
This is an eco-friendly way to oxidize copper and sterling silver. The process takes four to six hours. Here is what you need:
- Two or three hard-boiled eggs (boiled for at least 5 minutes; the yolk should be solid).
- A small shallow dish on which to place your metal or jewelry pieces.
- A plastic container with a tigh- fitting lid, or a Ziploc bag. The container or bag must be large enough to hold the small dish plus the hard-boiled eggs with room to spare.
Chop the boiled eggs. Place your jewelry or metal pieces on the small dish. Add the chopped boiled egg to the plastic container or Ziploc bag. Place the small dish in the middle of the plastic container or inside the Ziploc Bag. The egg should not touch the metal or jewelry pieces. Cover with the lid or close the Ziploc Bag. Leave it alone! You will be tempted to look but don't! Using a Ziploc bag or a clear plastic container will help you withstand temptation. You can open the container or Ziploc bag when the metal or jewelry pieces darken to the color you want. Throw away the eggs, and shine your piece leaving some of the detail oxidized.
Using Household Ammonia for Copper and Brass
Using the fumes of household ammonia to oxidize metal is really quite easy and is an inexpensive way to oxidize copper and brass. I have tried this method on finished pieces that included freshwater pearls and turquoise which are usually considered delicate materials. All you need is a clean pickle jar with a lid, a piece of wire or fishing line to suspend your piece, and clear ammonia. It is a little smelly, but if you are quick the smell should be no problem. At no time should the metal or finished jewelry come in physical contact with the ammonia liquid; it is the fumes that will produce this patina. I do not know the scientific reason why, I just know it works!
First and foremost, clean your piece of brass or copper with either alcohol or acetone to remove any oils or dirt so that the patina is consistent throughout the piece. Do not touch the surface that you want to patina.
Pour about one inch of ammonia into a pint or quart size glass jar.
You can use wire or fishing line to suspend the metal or piece of jewelry just below the mouth of the jar. I taped the ends of two pieces of fishing line to the outside of the jar to create a little cradle. The piece must not come in contact with the liquid ammonia.
Screw on the lid and wait a couple hours. You can check the piece to see what color you want to stop at.
The ammonia odor on your piece should fade quickly, but if you want, you can leave the piece out for a while before very gently buffing out any high points for contrast.
Using More Traditional Chemicals—Safety First!
Of course you can use the tried and true, non-eco-friendly method of adding a patina to your metal with the use of chemicals like Liver of Sulphur, Black Max, and Antique Patina Solution. Some chemicals can be caustic and must be handled with care, both during the process of patination and while disposing of the chemicals afterward. Here are some safety tips:
- Make sure that you have a well-ventilated area to work in.
- Clear off your work surface and lay down paper, because accidents do happen.
- Always have a cup or bowl of clean water at the ready, as well as a bowl of water with a little baking soda mixed in. I usually take old coffee mugs and fill them up about halfway and add about a teaspoon of baking soda.
- Have paper towels, old t-shirts, or clean rags ready in case of spills, and to dry off your pieces after you rinse off the chemical you are using.
- Use safety glasses. Yes, no one likes to wear them, but are you willing to jeopardize your eyesight for one accidental splash? I think not!
- Use rubber/nitrile gloves. I prefer nitrile, as they are a bit thicker and sturdier than the thin latex or plastic gloves. They do cost more but I reuse them as many times as I can before they break. I just wash my hands with the gloves on when I am done, and pat the gloves dry with clean old towels before I take them off.
- Have lots of water handy. I personally like to use running water when I can, but when I teach classes that is not always possible, so a gallon jug of water is always at the ready!
Have these things on hand when you "patina" metal.
- Cotton swabs, cotton balls, or cotton pads
- Brass brush (this can get wet)
- Stainless steel brush (this shouldn't get wet)
- Green scrubbie pads, of the type you use for scouring dishpans. You can find them at any grocery store. My favorite brand is 3M.
- ProPolish pads. These are spongy pads that contain permanently bonded micro-abrasives. They are used to shine up the highlighted areas of your patinated pieces. You can purchase these at most online jewelry supply/bead shops.
- Pro Polish Pads
You can find Pro Polish Pads here. Fusion Beads is a great one-stop shop for all your beading needs. I love their Crystal Mixes.
- Cool Tools Patina Gel: Liver of Sulfur in Gel Form, 1.25 oz
This is my favorite form of Liver of Sulphur because it is so versatile. I can use it straight from the bottle, using a paint brush or cotton swab to apply it directly where I want, or I can dilute it in hot water to dunk the whole piece.
- Reactive Metals: Antique Patina for Copper and Brass
This is hands-down the best and fastest patina solution for copper and brass. A little goes a long way so use it very sparingly. I usually dip a cotton swab in water, place a drop or two of this solution on the swab, and rub it on the piece.
This is the wire-wrapping Bible. It is my favorite wire-wrapping book, and it also covers patinas.
Did you try these methods? Did they work for you? Let me know!