Chemical Responsibility – Disposal solutions for the studio
By Helen I. Driggs, Managing Editor
Excerpt from the Jewelry Artist
One of the simplest things you can do to lessen negative environmental impact is to reduce chemical use in the studio and select less-toxic alternatives for those that can’t be avoided.
The most commonly used studio chemical is pickle, and many jewelers are making the switch to citric acid pickle, a less-toxic alternative that is now available from major suppliers. When handling acids, employ proper safety precautions, and mix according to the manufacturer’s instructions. Citric pickle should be used warm, with proper ventilation, to reduce required cleaning time. It takes a bit longer than other types of pickle, but citric pickle is still quite effective, and many jewelers prefer it.
To reduce the amount of pickle you need, use a small potpourri size warming pot to replace larger crockpots. Jewelry items are small, so this little pot will serve most jewelers’ needs, reduce chemical use, and save money. When it comes time to change spent pickle, you will have less to dispose of, which will make it easier to follow proper disposal procedures.
When used properly, a pickle solution will work effectively for many months, or even up to a year before it needs to be changed.
To keep your pickle strong, avoid introducing baking soda into the solution. Be sure to rinse tongs, baskets, and jewelry from your neutralizing bath before returning them to the pickle. As water evaporates from the solution, simply add more water. If the pickle is weak, add more acid. Steel adds an electrical charge that turns pickle into a copper-plating bath. However, as soon as the steel is removed, the pickle can be used again as normal. On the rare occasion that the solution contains small steel particles that can’t be removed, it will need to be changed.
At some point, every jeweler has at least one chemical, such as pickle, which requires disposal. To preserve the integrity of our environment, it is important to follow proper disposal procedures for all studio chemicals. Each region is governed by different federal, state, and local requirements for hazardous waste disposal. The guidelines offered here are approved by the State of California, which has some of the most stringent regulations. Following them will ensure your safety and the health of the environment.
Citric acid by itself is not classified as a hazardous material. However, after it has been used as a pickling solution, it contains copper, which is a heavy metal. Therefore, used pickle is a contaminated solution, which is hazardous, and must be disposed of properly. Commercial sodium bisulfate pickle is a stronger acid that also becomes contaminated with use. Neutralizing pickle will not remove the copper.
Therefore, even neutralized pickle is considered a hazardous material. All oxidizers, including liver of sulfur and other proprietary oxidizing solutions, are also hazardous materials. Collect hazardous materials in clearly labeled plastic containers with tight lids for storage in the studio and during transportation to an appropriate disposal facility, preferably with their original labels.
In San Francisco, residents who are hobbyist jewelers can drop off hazardous materials at the county hazardous waste facility free of charge during business hours. Small businesses can drop off small quantities of hazardous waste, up to 27 gallons at time, to the VSQG (Very Small Quantity Generator) disposal program. Disposal fees are $5 per gallon for acids, $6 per gallon for oxidizers. Collect spent pickle after most of the water has evaporated, without adding baking soda, to reduce volume.
Check with your local agencies to find out how to dispose of studio chemicals properly in your area. The proper agency can be found with a Google search using the key words ï¿½ghousehold hazardous waste collection programï¿½h along with the name of your city or state. Often household hazardous waste collection agencies also handle hazardous waste collection for businesses or can refer you to the proper authority.
Each day, the choices we make are a part of the cycle of life. We all live together, sharing one earth. The choice is yours: to pollute, or to preserve and protect. Take steps now to implement safer and more environmentally friendly practices – at your bench, and in all aspects of your life.
Mary Ann Scherr
I took an etching class with Mary Ann and learned her method for neutralizing nitric acid etchant. Remember, nitric acid is a very aggressive acid, and baking soda is a weak base. Acids and bases will become neutral when mixed, but you’ll need more baking soda by volume than nitric acid to get to neutral because of the different strengths.
When it comes to disposal, here’s what Mary Ann does: ï¿½gI drop baking soda into the acid bath until it forms a small mountain. The baking soda will continue to bubble like Alka-Seltzer. A dry mountain of soda usually indicates enough – there’s no need to test [the ph]. The bath is then neutral. I flush the container with water and flow it over the grass or flowers, since it is now capable of making the grass and flowers grow happy!”
Although I haven’t tried this myself, I guess the nitric in the neutralized acid is a lot like commercial nitrogen fertilizer, and the dissolved copper in the bath will keep the slugs at bay!
Pickle, Rinse, Dry – Why?
How many times do we use that sequence in our project directions? If you are new to jewelry making, you may not know what it means or why we do it.
Basically, pickle is a solution used to soak or steep in. With food, it’s usually salt, vinegar, and water – which will also work somewhat on some metals as well. Trust me – next time you finish a jar of baby dills, save and strain the juice and drop a piece of cooled, torched copper or an old penny in there for a few days at room temperature. It will come out shiny and bright and smelling really good! If you’re in a hurry, put that pickle juice in a crockpot and heat it up. The cleaning will happen faster with a hot pickle solution.
Cooking aside, metal pickling typically means acid dipping to chemically remove surface oxides from metals subjected to heat during annealing, soldering, or casting. Pickling also removes other crud – like fired-on flux, carbon, or investment. For the faint-hearted or eco-minded, the commercial safety pickles that are typically used in the studio are a very weak acid concentration that is easily neutralized if you don’t want to hold them unneutralized for longterm storage. Just add baking soda to a room temperature batch of spent pickling solution. You’ll know it’s spent when it’s bright, electric blue – like Paraiba tourmaline. Stir gently with a plastic utensil. It will foam and bubble a bit. Let the mix sit for a few hours to neutralize the batch. Then, pour the neutralized pickle into a clean plastic jug, label it, and take it to your recycling center on hazardous waste day if your locality requires it.
The most important thing to remember is not to toss a hot piece into pickle to quench it. The steam that rises from doing so will be acidic and attack the lining of your lungs as well as the surfaces in your studio. Quench in water instead, then pickle.
There are also organic, but slightly less aggressive pickle solutions you can mix up at home, like cider vinegar and salt mixed into a paste, or food-grade citric acid. Remember Tang? That juice mix makes a great cleaning solution. If you don’t believe me, try running a quarter-cup in an empty, stained dishwasher – no more brown, hard water stains when you’re done! A thick slurry of Tang mixed with water makes a great soaking solution for dirty, oxidized metal.
Some patinas are so fantastic you want to cry when you see them. But the chemistry involved in creating them might also make you cry if you think too hard about it. The most non-toxic patina out there is time. Sadly, most of us don’t have that, so we settle for chemicals. I have a stringent set of rules in my studio for chemical patinas, based on common sense:
1. Don’t mix more than you need.
2. Dispose of them properly.
3. Try other alternatives when possible.
I like the non-corrosive, commercially prepared patinas because I can pour out a scant quarter-teaspoon and paint them on with a brush. I work in white plastic photography trays when I patina, and soak up any excess with a paper towel. Then, I let the fluid evaporate from the paper towel and put that in the trash. I rinse the tray in the sink and let the water run into it to clean my patina brush.
If I have more time, I’ll fabricate a silver piece completely, and seal the piece in a Ziploc bag with half of a hot, hard boiled egg. The fumes from the egg will oxidize the silver gently after a day or so. Throw out the egg when you’re done, and give the piece a scrub with some dish liquid and a soft toothbrush.