Behold the metals supplier, lord of all things shiny. He fills your crucible with casting grain and makes sure you’re always one sheet ahead of the game. But perhaps more important than his ability to make metal magically appear at your door in 24 hours is his expert advice when your solder won’t flow, your castings are porous, or you’re just about ready to turn off your torch-for good.
We spoke with a number of metals suppliers to find out what their customers commonly want to know. From metalworking problems that constantly reappear to recent concerns about new alloys hitting the market, they shared with us some jewels of wisdom.
What’s the big deal about 950 palladium?
When a new (or relatively unused) metal comes into vogue in the jewelry industry, metals suppliers can expect phone calls from customers wanting to know more. According to many of the metals suppliers we spoke with, the questions that have been popping up most recently on their customer service calls concern the jewelry industry’s newest white metal, 950 Palladium.
“Many people are still testing the waters,” says BJ Williams of Johnson Matthey in New York City. “They want to know if palladium is really selling, or if it’s just some fad, before they buy into it.” Williams says that from all the bites his company has been getting, palladium isn’t a here-today, gone-tomorrow metal.
In addition to feeling out metals suppliers to gauge the popularity of the metal, manufacturers are also concerned about marketing it to consumers. Daniel Ballard of Precious Metals West/Fine Gold in Ontario, California, has spent many hours educating callers about this new metal.
“The first question I get is, ‘How do I explain this metal to consumers,'” says Ballard. “I tell them it’s a platinum family metal, 95 percent pure, it’s got a bright, white color, and it doesn’t require rhodium plating.”
How do I cast 950 palladium?
Ballard says that manufacturers who experimented with palladium in the ’50s and ’60s are concerned about en-countering the same problems they had years ago with the metal’s poor castability. “They’re not the same alloys that were around in the ’50s,” he says. “Those alloys were designed to machine earrings and brooch pins. The common ruthenium alloys around back then posed huge problems for the investment caster. The alloys we have now are designed to be cast.”
Stewart Grice of Hoover & Strong Inc. in Richmond, Virginia, has also been getting calls about working with the new 950 palladium alloys. (For more information, see “Palladium Premieres,” March 2006 AJM.) “People ask if they can cast it like gold. I tell them no, cast it like platinum,” says Grice. “If you can cast 90/10 platinum/iridium, you can cast 950 palladium.”
Both metals suppliers agree that casting with a machine designed for platinum group metals is far superior to attempting to cast with a torch. “The sophistication of your equipment has a direct impact on your success using these alloys,” says Ballard, who suggests casting in an induction machine, possibly under vacuum and an argon backfill.
“If you do cast with a torch, do not use hydrogen,” advises Ballard. “Palladium tends to absorb hydrogen, which leads to porosity. Opt instead for propane or natural gas.”
How do I work successfully with rose and red golds?
Trend forecasters have been talking up the popularity of rose and red golds for 2006, and manufacturers are heeding their predictions, working more and more with these sometimes pesky alloys. Ballard advises manufacturers who want to cast rose or red gold to ask their metals supplier for an alloy specifically designed for investment casting. “You may have to make small compromises in color for ease of use,” says Ballard, adding that many 14k red alloys offer cleaner castings, easier setting, and more durability than 18k reds.
While 14k red alloys may also provide fewer issues when fabricating, those who opt to use 18k reds might heed Grice’s advice: “Directly quench after you anneal. Don’t let it go cold at all. Get it in that water.”
Although red and rose gold alloys are always going to be hard, they don’t always have to be difficult to work with if you know a few tricks.
Why is my tarnish-free sterling silver alloy tarnishing?
First things first: There is no such thing as stainless sterling, says Rich Carrano, director of technical services for Stern Leach/Hallmark Sweet/Excel, in Attleboro, Massachusetts. The many tarnish-resistant de-ox sterling silver alloys on the market may take longer to turn, but tarnishing is inevitable. If you want to get a better idea of to what degree these alloys are tarnish-resistant, Carrano suggests asking your metals supplier for the results of any tarnish tests they’ve run. “Tarnish is caused by a number of factors, two of the main culprits being sweat and sulfur,” says Carrano. “We test our alloys to see how they react to both sweat and sulfur, and we’re happy to share that information with our customers.”
What type of solder do I use for the job?
When it comes to choosing a solder for your repair job, whether you are working in gold, silver, platinum, or palladium, don’t take the easy way out, suggests Grice. “The general rule is that it’s always best to use hard solder because it will be the closest match to the alloy you are soldering,” he says. “While medium and easy solders are easier to control and use, they are likely to differ more in color from the original alloy and perform differently than the materials you are joining.”
In addition, adds Carrano, using hard solder for joining can be beneficial down the road if you need to perform a repair on the piece. “If you use a lower melting temperature solder for joining because it’s easier to work with, you may end up melting it later when you go to do a repair.”
But it’s a good idea to check with your specific metals supplier if you are unsure of the correct solder to use for a specific job. “Solders vary from company to company,” says Ken Babayan, product manager for David H. Fell & Co. in Los Angeles. “If you want to find the best match for the sheet and wire product you are using, it’s usually best to go with solder from the same company, and ask their advice about which solder is best for a specific project.”
When in doubt, check with your metals supplier before firing up your torch.
Why is my solder behaving badly?
In addition to questions about choosing the right solder for the job, metals suppliers also field inquiries about solder behaving badly. For example, Babayan gets frequent calls from customers who complain about solder not flowing. “They say the solder refuses to flow, and if they turn up the flame, the piece melts,” he says. “In many cases, the pieces being joined are dirty-they had a film of oxidation from the beginning, or they developed one during the initial heating process, which occurs when the jeweler doesn’t apply enough flux. Flux acts like an oxygen sponge, but there is a limit to the amount of oxides it can hold before you have to re-flux and start over.”
New alloys on the market can also pose problems. Many of Grice’s customers who are experimenting with the new 950 palladium alloys have been complaining about brittle solder joints. Grice attributes this to overheating and cautions jewelers to keep palladium solders liquid for as little time as possible. “This should eliminate brittleness in the joint,” he says.
Why are the billets I’m making from my scrap cracking?
Grice hears this question from customers at least once a week. A jeweler melts his scrap into a billet to make some sheet or wire and gets frustrated when she or he finds that the billet is breaking up. “It’s because they haven’t done it right,” says Grice. Most jewelers make the mistake of using an open-face ingot mold as opposed to a vertical ingot mold with all but one end of the bar enclosed.
“When the metal solidifies, it shrinks,” says Grice. “With an open ingot mold, shrinkage occurs on the total area of the open face, creating internal porosity. With the vertical mold, the bar has a better chance of progressively solidifying, minimizing porosity. As a result, it’s best to keep the metal protected.”
It’s also important to use a reducing flame with gold or silver to prevent oxidation. And, Grice adds, you should never add any casting alloys that contain silicon to the mix. The silicon will wreak havoc, causing cracks and breaks when you start to roll the ingot. “Silicon casting alloys do not make good mill product alloys,” he says.
Can I use my refining lot to buy more product?
In most cases, metals suppliers welcome this practice. Some even offer discounts to customers who use their refining lots to purchase new metal. For example, Hoover & Strong offers a 1.5 percent discount if customers use their refining return to buy products. Ask your metals supplier if they offer any such terms.
In addition to offering discounts on purchases made with refining returns, some metals suppliers provide vault accounts-a way to hold your metal aside until you want it or need it. The amount of metal recovered during refining goes into the vault and stays there, while the market dips or rises. At David H. Fell, for example, ounces of precious metal recovered from refining are held for the customer until he or she is ready to fabricate them, sell them, or ship them to a contract service provider.
Can I get an advance against my refining lot?
This is another service that some metals suppliers provide that can be a financial boost in a high metal market. At Johnson Matthey, for example, if a customer sends in platinum scrap for refining and requests an advance, the company will loan them 75 to 90 percent of their refining lot at a minimal charge. “Letting people borrow their metal back as opposed to buying it outright or waiting weeks for refining returns helps them financially,” says Williams.