Plumb Wonderful

Solder isn’t usually the sort of thing that makes bench jewelers break into paeans of praise. In gold work, the wide selection of colors and melt temperatures available is mostly taken for granted, and in platinum work, the serious limits of traditional platinum solders are normally the source of curses, not compliments.

But thanks to several new plumb platinum solders, jewelers working with platinum have found reason to sing the praises of solder. “It’s a real advantage to trade shop workers and retail trade workers to be able to work with platinum in the way we’ve traditionally worked with gold mountings-sizing while you wait, and not having to send [a piece out for laser welding],” says David Huffman, a bench jeweler for Federico’s in Traverse City, Mich., and owner of his own trade shop, David L. Huffman Studios, Inc.

“They are a better-performing solder-they’re just better,” says Tim Dooley, a bench jeweler for Dacels Jewelers in Bellevue, Wash. “They contain such a high percentage of platinum, they marry the metal much more closely. The hard and the medium plumb solders very closely match in color the platinum/iridium we use.”

The not-so-good old days.To understand why jewelers working in platinum are so excited about these new solders, one must realize how few options bench jewelers traditionally have had when repairing platinum jewelry. While goldsmiths have long had their choice of entire catalogs of gold solders in different melting temperatures and colors, platinum jewelry repair has offered jewelers only two choices: Weld the seam or use a platinum repair solder containing little or no platinum.

Welding produces a strong, nearly invisible seam, but it requires practice and skill to bring the metal just to the melting point without damaging the rest of the piece. In addition, the technique can’t be used near stones because of the high temperatures involved, and it can’t be used on platinum-cobalt alloys, which tend to oxidize too quickly for a successful weld joint to form.

“There’s a limit to what you can weld,” says bench jeweler Peter Rowe of B. Sholdt Jewelers in Seattle, Wash. “It’s good for sizing seams, and it’s good if you can do a lot of filing. But if you’re actually assembling jewelry instead of just sizing, you’re pretty much using solder.”

Even laser welding, which permits delicate repairs without the risk of damaging stones or destroying the piece, has its limits. “Even the laser won’t do everything,” observes Rowe. “It’s line of sight. Often when you’re assembling jewelry you have a capillary seam that you have to seal all the way down, and [the laser] won’t do that.”

When welding won’t work-or when the shop doesn’t have access to a laser-jewelers turn to solder. But traditional platinum repair solders come with their own problems. Because they generally contain little or no platinum, the color match isn’t perfect and can result in a visible solder seam. That seam may become even more visible when the jeweler attempts to put a final polish on the piece: The softer repair solder tends to polish out of the seam, leaving an undercut.

“Standard platinum solders are kind of crappy things to work with,” says Rowe. “They flow easily and solder easily, but they look terrible. You can see the color, and the solder polishes out. If you’re putting a head together with just wire, and all you’re asking [the solder] to do is seal two wires together, it’s fine, because you don’t see it. But if you’re doing something where you polish [the seam] down again later-such as sizing-standard solders stick out like sore thumbs.”

“It’s difficult to explain to a customer why there’s a seam and why they have to live with that,” adds Huffman. “I’d have abandoned solders in favor of fusing because of the quality of the seam, but that’s practically impossible if there’s 18k gold in the assembly, or if there are stones near the bottom.”

The next best thing.Now, jewelers have a third choice: a plumb platinum solder with three melting temperatures and nearly perfect color matching for most platinum alloys. Developed by Precious Metals West in Los Angeles, the patent-pending 90%-95% platinum solders rely on the addition of indium and gallium to produce flow temperatures of approximately 1,300° C, 1,400° C, and 1,500° C.

Because the platinum content of the solders so closely matches that of the metal being worked on, most jewelers find the color match is nearly ideal. The hardness closely matches the surrounding material as well, reducing polishing problems. “The new hard plumb platinum solders are very white. You can’t see it after polishing with the naked eye,” says Dooley. “If you use 1,700° C [repair solder] what you’ll get is a definite color line, and you will undercut it ever so slightly.”

The result is not only a better quality repair but also greater creative freedom. “It’s always been a problem that if you’re making [platinum] jewelry by hand, you don’t want to show a seam, so you design your piece accordingly,” says Tom Arnold, the owner of Facets, a retail store in Arlington, Va., that specializes in custom work. “[You’d design it so] the seam is at a corner, or covered by some ornament, or use some other way to hide it. Now you can do anything. With this new platinum solder, there’s no seam, no color difference. It’s great.”

But although the plumb platinum solders offer distinct advantages over traditional solders, bench jewelers are also likely to find they need to learn some new tricks to cope with the solders’ limitations. Because the plumb solder will oxidize, jewelers must give some thought in advance to how they will polish the seam when the soldering operation is complete. “The big difference [between traditional solders and plumb platinum solders] is [that plumb platinum solders] oxidize. They look kind of crummy after you finish flowing,” says Rowe. “But they polish right up. If you can get a brush or a string in [to polish with] it’s not a problem-it’s just cleaning up the metal. But if it’s a complex assembly-for example, if you’re putting together a traditional three-stone basket-and you put solder on the inside of the head, which happens to be the easy way to do it, then it’s harder to clean up. You can’t get a rubber wheel in there. So you need to put the solder on the external surface.”

The oxidation also means jewelers can’t use the old gold-solder trick of balling up the solder on a solder pick to transfer it to the seam. “Anytime you heat this stuff up before it’s being melted where it’s really going into the joint or seam, people wind up having it oxidize,” says Daniel Ballard, national sales manager for Precious Metals West. Flux, which is sometimes used to prevent oxidation in other metals during soldering, can’t be used with platinum because of problems with contamination.

One solution, which Ballard credits to Pasadena, Calif. platinum jewelry designer Christian Tse, is to bring the platinum piece up to temperature, then use tweezers to place the solder. “Red hot platinum is sticky by nature,” he observes. “So you can bring the jewelry up red hot, then place a little clipped piece of cold platinum solder on it, and then when you come back with the torch, you’re all set.”

Spit ‘n’ polish.For jewelers accustomed to using a bit of flux to hold the solder in place, Ballard passes on another old-timers solution: spit. “Flux actually disturbs the platinum, and gives it a blemish,” he says. “One trick is to use a little saliva [instead].” Plain water should work equally well for those disturbed by the notion of using spit to fix solder in place, notes Arnold.

Ballard also recommends that jewelers use a reducing flame-instead of the oxidizing flame commonly used with platinum-to prevent oxidation. “An oxidizing flame is for casting, not soldering,” Ballard says. “A reducing flame is better for soldering. For welding you need an oxidizing or at least a neutral-to-oxidizing because you’re melting that 90/10 or 95/5 metal, and you do have [problems] with hydrogen embrittlement. But for soldering, you don’t need that much heat.”

Most jewelers will also find that the plumb platinum solders do not flow quite as easily as the gold and lower-temperature platinum repair solders to which they’re accustomed. “It seems to take more of it,” observes Arnold. “I will put a patch of solder on a joint, and I’ll solder and get through and think I should have used more. Because it won’t flow, it leaves a small valley, so you have to build it up so it’s convex instead of concave.”

“[This solder] is thick; it sticks around,” admits Ballard. “You can’t wick or sweat solder with it, as you can nickel white gold. So you need careful placement and volume of the solder-just the right amount, not too much, not too little [for best results].”

Despite the limitations, though, few bench jewelers have anything but kind words to say about the new solders-and most say they’ll never go back to using high-temperature repair solders. “Since we got the new solders in, the 1700 and 1500 [repair] solders just kind of sit there,” says Dooley. “We haven’t run out of them and I don’t know that we ever will.”

“I’d have to say there’s no comparison [to repair solders],” agrees Huffman. “For the kind of application we’re doing-mostly ring resizing-I’d have to give them a 10. There are a lot of mounting situations I simply wouldn’t be able to do with traditional solders unless I wanted to live with a visible seam. Now I can size rings that have stones in them and rings that have an 18k assembly, where before it was just out of the question unless I wanted to live with a seam.”