Tips for recovering precious metal particles
Most jewelers know how to handle their precious metal scraps: they separate their scraps by metal, dry out ultrasonic solutions so they just ship the metal-infused sludge, and they keep their bench sweeps separate. But what about the precious metal scrap that’s not easy to see—that fine metal dust that gets tossed into the air from a flex-shaft or polishing machine, settling here, there, and everywhere? While you will never be able to capture and refine every single speck of metal that enters your shop, there are steps you can take to maximize how much of that fine metal dust winds up back in your wallet.
Suck It Up
Dust collectors make working at the bench cleaner, but they can also help to speed up the process of collecting sweeps and scraps for refining. At least, when they’re sized and positioned properly at the bench.
When Judy Hoch of Marstal Smithy in Salida, California, bought her Handler Super Sucker vacuum dust collector, it came with a fish-mouth attachment that measured about 14 to 15 inches wide and had a 4- to 5-inch opening. Because she wanted the attachment close to where she was working, Hoch had to clear off half her benchtop to accommodate it.
“It was large and inconvenient,” she says. “It was also not really effective because the area of intake was so large. It didn’t collect material well enough.”
To make it more efficient, Hoch disposed of the fish mouth and attached a piece of PVC pipe to the vacuum tubing. She then created a new bench pin from a piece of ¾-inch-thick wood with an opening to accommodate the end of the vacuum hose, which rises up underneath the pin. She added a mesh screen to the opening of the tube to prevent anything large from falling into the vacuum. And when she’s done using the vacuum, she can easily swap out the bench pin for another.
If you set up a similar system, make sure you use a vacuum dedicated to bench sweeps, advises jeweler Arthur Anton Skuratowicz. He’s had good results with a used Rainbow-brand cleaner that utilizes water filtration. “The water filter has several benefits: Dust is virtually eliminated, the heavy metal particles sink to the bottom while the light particles float to the top, and the fast agitation separates some of the metal and buffing compounds. When you are through vacuuming, let the water settle, skim the materials off the top, and pour the water through a mesh filter or into a container to evaporate. Left behind will be a slurry of metals and dirt.”
If you’re worried about precious metal particles that might still be floating in the water, add a couple of drops of water clarifier, which is a chemical used in ornamental ponds to remove particles suspended in the water. This will allow any remaining particles to fall to the bottom.
You can also use a wet/dry vacuum in a similar manner by attaching a new device called the Dust Deputy to it. The Dust Deputy is a funnel-shaped system that uses centrifugal force to separate and remove dust and debris before it reaches the vacuum’s filter, which is ovften just a thin piece of paper that eventually lets small particles through. “You can also install a magnet to the bottom of the funnel to catch any steel, keeping your sweeps cleaner,” says Skuratowicz. “Companies that refine sweeps pay higher for clean sweeps than dirty sweeps.”
Spic and Span Floors
Despite your best efforts to keep your shop floor swept and clean, tiny dust particles get stirred up in the cleaning process and settle back down once you’ve gone around with your broom. When Brett Gober of Freedom Design & Contracting in Hannibal, Missouri, got tired of seeing dust reclaiming his floor, he turned to a bit of technology—a Roomba vacuum cleaning robot—for help.
“Each morning when I arrive at the shop, I press a button and Roomba takes off from its charging station, wandering all over the shop floor to collect leftover dust not contained by my room air cleaner or the floor duct attached to my polishing dust collector. The robot’s rotating sweeper arm gets into even the smallest cracks and crevices.”
Gober notes that among the dust Roomba collects are small particles of metal that he thinks would otherwise have gotten tracked out of the shop on the bottom of people’s shoes. Now, thanks to his robotic maid, he can add them to his refining sweeps. “Even the tiniest of particles add up quickly,” he says.
If you’re feeling really ambitious and extra determined to keep your floors clean, Skuratowicz says you can adopt a ventilation system normally seen in woodshops.
“Many woodshops have a giant suction machine with hoses hooked up to each workstation,” he explains. “The hoses suck up the sawdust and put it into one big bag. But the cool thing is that they also have slits at the floor level hooked up to the suction system. So at the end of the day, they can sweep directly into the vents so they don’t have to scoop up anything. I bet you could even add ventilation vents at the bottom of a bench so you could just whisk metals right into the vent system.”
Keep Yourself Clean
In most jewelry workshops, there are a lot of precious metal particles thrown around by tools and equipment, and some of that metal dust is bound to wind up on your clothing. One way to avoid losing that precious metal is by wearing a uniform in your shop. Having a dedicated set of uniforms that don’t leave your shop means you won’t run the risk of some of the dust walking out the door. When your uniform gets too worn, send it your refiner, where it can be burned and the precious metal recovered.
If uniforms aren’t a viable option for your shop (or you just don’t want to wear the same thing every day), then, at the very least, you should wear an apron to keep metals from accumulating on your clothes. Thin leather aprons with a smooth surface work best, but cloth aprons are better than nothing. And, like the uniforms, those cloth aprons could also be sent in for refining.
If the idea of buying uniforms and aprons only to later burn them up seems a little wasteful to you, you could also invest in a small washing machine for your shop. Skuratowicz points to the appliances that are manufactured to meet the demands of the recent tiny-home trend. There are small, portable washing machines (both hand-crank and automatic) designed to wash and spin dry small loads of laundry.
“These mini-washing machines come on wheels and can be hooked up to a sink,” says Skuratowicz. “When the water filters out, you can pour it through a fine filter and recover metals. Some have an internal lint filter which with or without some doctoring may catch the sweeps.” Although he hasn’t tried them himself and he admits that it would require a bit of an initial investment, the precious metal dust recovered from the washed uniforms and aprons could quickly add up. Plus, “it would keep your apron clean for meeting your customers,” he adds.