Thoughtful Studio Infrastructure

Oregon College of Art and Craft implements new infrastructure changes. A mini chemistry lesson about sodium bisulfate pickle, by Glenn Glass, is included and sheds light on "electroless" plating and why pouring pickle down the drain really is a bad idea.

Portrait Jennifer Wall

 

 

 

By Jennifer Wall

OCAC metal recycling bins, ethical metalsmithsThe Oregon College of Art and Craft (OCAC) Metals Department has recently implemented several infrastructure changes to its studio practices and policies in an effort to mitigate our impact on the environment.  By addressing a few of the areas in which metalsmithing practices can be toxic or wasteful such as metal reclaiming, cleaning, and drying, we are able to more thoughtfully use our limited financial and material resources.

Scrap metals bins OCAC, recycling, ethical metalsmiths, studio practicesMetalsmiths have always recognized the infinite lifespan of many metal alloys, and have used technologies inherent in the field to reclaim unusable or discarded material. The OCAC Metals studio has long practiced collection and recycling of copper, brass, bronze, aluminum, and steel.  The small and often unusable bits weigh enough at the end of the year to bring to a recycling center for cash.

sheet and wire recycled silver ingots

anvil, ingot mold, recycling metal, OCAC, ethical metalsmiths

Reclaiming more precious metals is central to our curricular programming in both the degree-seeking and community classes. First year degree students are taught to cast ingots and mill them out in multiple ways, and we recently offered an in-depth community program class that taught the end-to-end process of reclaiming more precious alloys.

Recycling other materials also requires clear labeling and organization; the OCAC Metals studio centrally collects and recycles all materials commonly recycled by the city of Portland, Oregon.  We also recycle our pickle solutions. reclaiming sodium bisulfate pickle, ethical metalsmiths, studio practicesWhen pickle (in our case, a sodium bisulfate solution) becomes spent, it commonly turns blue and loses effectiveness *.   Instead of neutralizing the bath to dispose of it and making a brand new solution, we use steel wool to attract the copper out of the spent bath, and then recycle the copper plated steel after filtering it out of the bath through cheese cloth in a meshed funnel.  A bath can usually be reused and refreshed in this way up to 4 times before it needs to be changed, dramatically lengthening the time the pickle bath can be used.   This reduces the studio’s cost for purchasing new pickle as well as the amount of neutralized pickle that gets thrown out.

In an effort to lower the amount of all throwaway items, such as paper towels, we have also provided a studio towel use system.  towel collection, OCAC, responsible studio practices, ethical metalsmithsThe department stocks cabinet drawers with 30 hand towels that are laundered 2-4 times per month by studio work-study.  All studio users are allowed access to these towels.  In conjunction with this towel system, the department incentivizes individual towel usage: once per week, the studio manager chooses a student who is utilizing a towel attached to their apron in some way instead of paper towels to receive a five dollar studio store credit.

In our efforts to reduce studio waste and inefficiencies, the OCAC Metals studio has built infrastructure around reclaiming, recycling, and cleaning metals.  We have seen a reduction in material costs as well as waste products coming out of our studio.  We are excited to hear from others regarding their own studio practices.  For questions, comments, or ideas, please contact studio manager Jennifer Wall (jwall@oac.edu) or department head Christine Clark (cclark@ocac.edu).

For more information visit: Oregon College of Art and Craft / Metals Department

About the Author:

Jennifer Wall is the Metals Studio Manager and an instructor at the Oregon College of Art and Craft as well as an adjunct instructor at the University of Oregon in Portland. Her work has been shown in both domestic and international galleries, and employs a range of methodologies and material with a focus on the intersection between the machined and the haptic. Wall received her MFA from the University of Oregon in Eugene.
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* This change during pickling is commonly referred to as electroless plating and is extensively used in the mircoelectronics industry for making printed circuit boards and copper metal layers in microchips. When copper is dissolved in the pickle solution it alters the chemistry from sodium sulfate to copper sulfate. Copper sulfate is blue and the color is a rough indication of the copper concentration.
 
Copper sulfate is a salt (otherwise known as an ionic solid). Salts are compounds that are composed of metallic and non-metallic elements. Many salts are water-soluble. In solution, salts dissolve from the solid phase to aqueous solution, which means that the individual atoms or molecules become surrounded by water molecules. The atoms that used to make up a solid salt carry a charge- the metal atoms like copper carry a positive charge (positive ions) and the non-metal constituent, which in this case is sulfate (SO4) carries a negative charge (negative ions). These atoms/molecules remain charged (i.e. ions) in the aqueous solution.
 
Metals have different oxidation potentials that are measured in volts vs an arbitrary standard. This is a measure of how much the metal wants to be metallic vs. being an ion. Noble metals like platinum and gold ionize with great difficulty and have a positive oxidation potential. Metals that are less noble like zinc or sodium can oxidize explosively. Copper has an oxidation potential near the middle of the range of all metals. When a metal is inserted to the copper sulfate aqueous solution that is less noble than copper, it changes its oxidation state by giving off electrons. The copper ions pick up the electrons given off by iron (any metal with lower oxidation potential than copper will work) and are plated out of solution in the form of solid metallic copper.
 
How to get the most copper out of solution:

1)   Using a metal wool or shavings of a metal less noble than copper is best because the surface area for reaction would be large and electron exchange is surface dependent.
2)   The process could be further enhanced with electrical current but this will generate explosive mixtures of hydrogen and oxygen so is not advised.
3)   Concentrating the solution will enable the most copper removal since the reaction rate is proportional to dissolved copper concentration. A large volume of dilute solution would leave behind more copper after the steel wool treatment than an equivalent small volume of concentrated copper ions. Simply evaporating off the water is an easy way to concentrate the copper sulfate solution. The water will evaporate leaving most of the ions in solution.

Why worry about copper?
Copper compounds are very toxic and they are much more biologically active in the form of dissolved aqueous ions than as solid metal. By reducing the dissolved copper ions to solid metal copper the material becomes safer to handle and to dispose. The toxicity of copper salts is severe and it can actually kill off the beneficial bacteria that are necessary to the smooth running of the waste-water treatment plant. Also the waste treatment plans are designed to remediate organic wastes. Salts require a different remediation method that is just absent in city facilities so sending the waste stream down the drain is equivalent to dumping this waste directly into the river.
 
Additional notes provided courtesy of:

Glenn Glass, Ph.D. University of Illinois @Urbana-Champaign                                                             
Catherine Glass, Assistant Professor Natural History at Oregon College of Art & Craft; Pacific NW College of Arts