Laser Welding
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1. A customer brought in a two tone engagement ring with a platinum center head. The yellow gold prongs had worn away again while the platinum center still looked like new. I ask her if I could use something new to make them last longer. I explained how palladium was reasonably priced and a very durable platinum group metal. I reminded her how much she liked how the center head was holding up and ask her if she wanted similar wear on the baguette prongs at gold prices. |
| She happily agreed. She explained that she was very hard on her ring and that the last jeweler had used oversize prongs and she wanted the same in palladium. I prepped the prongs by grinding them all flat like the upper prong pictured here. Then I placed an oversize palladium Redi-Prong with an overlap of approx 25%. | |
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2. I adjusted the beam to .2mm and to the 14KPW 30ga wire power settings (approximately 225v. / 3.5 MS / 4 HZ / .2mm). I took a down shot like pictured to push some molten palladium into the gold to tack the prong in place. I overlapped the beam 70% on the Redi-Prong and 30% on the yellow gold. This melted the palladium and pushed it downward while melting the gold and allowing it to penetrate deeper into the host prong.
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3. Here we see all six prongs tacked in place. We now need to finish welding them to the host material before we add any filler. |
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4. We need to up the voltage about 5 V to penetrate deeper, so the penetration is deep enough to have solid metal all the way to the diamond. Come in with your shot like pictured so you get an even melt top and bottom. (CAUTION – low quality diamonds with flaws can easily be broken as the flaws absorb the laser energy thus heating up and resulting in uneven expansion. This can cause cracks. Also be cautious of small chips as they react the same way.) |
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5. Start at the edge where the baguette and the prong meet and work towards the middle. Work your way around the base of the prong until it’s all welded in place. Remember don’t hit your original tack spot first or the prong will lose its footing and fly off. |
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6. Now the Redi-Prong is secured all the way to the diamond and it is time to fill the backside. With a torch you would use a tiny ball of solder and then burnish it to hopefully remove all the pits. So we need to duplicate this action better with solid metal with the laser. |
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7. Take 30 Gage 14KPW wire and ball up the end to double the width of the original wire. The palladium white gold with approx 9 % palladium will have a slightly off white color. It offers us a nice color transition from bright white palladium 950 Redi-Prongs to the yellow gold. Widen your beam up about six notches so you melt the ball like the small circle pictured. It will spread out like the larger circle pictured and blend the metal into the Redi-Prong and the host material. |
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8. After you have all the metal filled as pictured here, it is time to smooth the joint. |
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9. Widen your beam to half the diameter of the prong and up your voltage another 3-7 volts. Shoot down from the inside top and push the metal smooth down the back of the prong. This further blends the transition point of the two colors. |
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10. Now tilt the angle of your shot so the melt footprint is a long oval. This diminishes the beams power and allows you to polish the area. After blending and laser polishing the prong tips I like to go straight to a knife edge polishing wheel to concentrate all the polishing force on the individual prongs to blend them seamlessly into the host material. |
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11. This is the finished ring. She picked it up and loved the look of white tips on her white diamonds. I reminded her it was solid white metal and wouldn’t wear off like rhodiumed tips. Until palladium Redi-prongs are available at your venders call Redi-Prong directly at 1-812-436-4155. There is no price savings buying direct from them. It’s just an availability option. After your venders get enough requests they will carry them. |
This article first appeared in Bench Magazine http://www.BenchMagazine.com |
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