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#11
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Need Help -- lost and found diamond -- defective ring?
Platinum-palladium alloys in Japan and China are usually 90%. Platinum
jewellery is rarely manufactured from 100 per cent platinum because the pure metal is Too soft to withstand the rigors of daily wear. (Sometimes Cobalt or Iridium is used instead however these are usually mixed to create a 95% Platinum alloy) To effectively shorten the ring they would have had to remove the diamond and cut out a small section of the shank and fuse it back together. Sometimes if the wrong solder is used (i.e. only fuse Iridium Platinum with Iridium Platinum. Only fuse Cobalt Platinum with Cobalt Platinum. Only fuse Ruthenium Platinum with Ruthenium Platinum.) This can cause a weakness however it is unlikely they would have made this mistake. It is improbable with normal usage for a platinum ring to lose its shape without being subjected to some extreme force. So is there any possibility that the ring was accidentally pressed/pushed/squeezed by a heavy force - if not have you thought about having the ring independently analyzed to check its metal purity levels? http://www.silverstall.com/silver_jewellery.html |
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#12
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Need Help -- lost and found diamond -- defective ring?
On Mon, 16 Jul 2007 08:28:34 -0700, in rec.crafts.jewelry silverstall
wrote: To effectively shorten the ring they would have had to remove the diamond and cut out a small section of the shank and fuse it back together. The diamond does not need to be removed for this in most cases. Platinum is a fairly poor heat conductor, so it's not too hard to keep the top of the ring with it's diamond, cool enough for the diamond's safety, while the back of the ring, needing to be fused, is worked on. The temperatures of that operation are, of course, higher than a diamond can withstand, but that does not mean the whole ring is exposed to those temperatures. And fully modern shops may have laser welders, which can work safely right next to a diamond, even with platinum. It is improbable with normal usage for a platinum ring to lose its shape without being subjected to some extreme force. When fully annealed, platinum, especially cast platinum, can actually be quite surprisingly soft and easy to bend. There can be quite a lot of variation from one platinum ring to another in this regard, depending on whether it's cast or fabricated/stamped, etc, or the degree to which a casting may have been work hardened in processing. And various alloys too can vary a lot. Some platinum rings are indeed quite stiff and resistant to bending or denting, etc, but I've seen more than a few that are quite soft and easily bent or dented. Platinum has a well deserved reputation for durability, but this is based more on it's toughness and resistance to being worn down by abrasion, than on it's stiffness or hardness. Many jewelry manufacturers today design their wares based on market desires more than on engineering concepts for the jewelry's durability, and some of the resulting jewelry is, in a word, really rather fragile. ( base that statement on having had to repair quite a large number of such pieces sent to our shop...) The ring in this instance does not appear to be overly thin, as are some, but if the ring was cast, using one of the softer alloys (cobalt platinum, for example, or a platinum/palladium alloy), and is still fully annealed, then it could be bent out of shape by forces that a normal and reasonable person would not consider at all extreme. Certainly, platinum rings are usually easier to bend out of shape than, say, nickel based white golds... Peter |
#13
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Need Help -- lost and found diamond -- defective ring?
Hi peter
I was looking at the image of the ring and unless I looked at the wrong one what I failed to make clear in my post was that this specific design looked reasonably thick and ought not to fall out of shape because of normal wear and tear. Having said that my browser/ screen resolution is widenening images so to me the shank looks a lot wider than it probably is. You of course right in saying the stone need not be removed however I was assuming they would not have used a laser welder. Personally I find it too difficult with such high heat avoiding the stone and I guess as a silversmith I am just used to having always to remove the stones. I take your point about the hardness - maybe its just the few platinum rings I have worked with that were difficult to reshape. |
#15
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Need Help -- lost and found diamond -- defective ring?
On Mon, 16 Jul 2007 22:07:42 -0700, in rec.crafts.jewelry silverstall
wrote: Hi peter I was looking at the image of the ring and unless I looked at the wrong one what I failed to make clear in my post was that this specific design looked reasonably thick and ought not to fall out of shape because of normal wear and tear. Having said that my browser/ screen resolution is widenening images so to me the shank looks a lot wider than it probably is. You of course right in saying the stone need not be removed however I was assuming they would not have used a laser welder. Personally I find it too difficult with such high heat avoiding the stone and I guess as a silversmith I am just used to having always to remove the stones. I take your point about the hardness - maybe its just the few platinum rings I have worked with that were difficult to reshape. The thing with platinum that fools people sometimes, is just how easily bent and dented it can sometimes be, when fully annealed. It's not so much just that it's soft, it's that it's a totally "dead" metal, in that it doesn't spring back at all when bent more than a little. Even sterling, fully annealed, springs back more, though it takes less force to bend it. Now, couple that possibility with the design of the setting, and what becomes possible is that any bending out of round of the shank can pull those side arms out of position, altering the tension on the stone, and thus loosening it. It's true that for most examples of this ring, with most wearers, it's thick enough, or looks it, to withstand easy bending. But people vary a lot, and some people just need heavier rings in platinum than one might expect, even without any sort of abuse or abnormal event. Clearly, the fact that the ring bent out of shape should not be considered just normal and to be tolerated. But it's less clear just why this happened, or what's to blame. Anyway one looks at it, though, the store should find some sort of solution to protect the stone. My own suggestion would be to fit an undergallery jump ring into the setting. This would be a wire ring slightly smaller than the diamond diameter, on which the stone would actually sit, clamped down onto it by the rest of the setting. That undergallery would serve to reinforce the setting as a whole, and isolate it mechanically from any deformation of the shank, so even if the shank gets bent, the stone stays secure. Such an undergallery, while visible from the side, can still be made fairly unobtrusive, and would make the whole setting much stronger. Since it's channel set, fitting this in by traditional means is a little trickier than with prongs, but is doable. For me, it would be easy, since I'd laser weld it in place right under the stone without removing the stone at all. With a torch, the stone would have to come out. As to diamonds coming out for working on platinum, though, the fact that platinum is usually welded with a sharp hot flame, working quite quickly, so the heat is quite localized to the weld area, coupled with platinum's low thermal conductivity (much much less than silver) means that even though the weld is almost white hot, you could have diamonds only a few millimeters away, depending on the thickness of the metal being welded, and they'd still be safe, IF you used proper heat sinking between the stone and the weld. A plain cross lock tweezer on the platinum at that point would be enough to block that heat transfer sufficiently. Of course, the usual practice of having the diamond very clean, and then coating it with a good coating of boric acid to protect it, is still needed. When doing sizings, where one usually is working on the back of the shank, with the stone in front, even careful heat sinking isn't needed. The stone simply won't get all that hot that far away. Silversmiths who're used to the thermal conductivity of silver are often totally unprepared for just how little even gold, not to mention platinum, conducts heat away from a joint. It really does mean different rules apply... cheers Peter |
#16
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Need Help -- lost and found diamond -- defective ring?
All the advice I've heard from this forum and from orchid has been of
tremendous help.. What I've ascertained is that the diamond fell out because of both a design and materials problem.. I have confirmed with the store that it is in fact 90%platinum/ 10%palladium which I have heard is tremendously soft? Their solution which they sketched for me was to put two claws underneath the ring to support the ring structure. Both Peter and another poster in orchid suggested to put a wire ring or circular cup underneath to support it. My questions are, 1) Would you recommend the wire ring or is two claws undeneath sufficient to support the diamond? 2) Given the new structure of either the wire ring or claws, is the 90%platinum/10%palladium reliable the design/ring? 3) I believe it is the store's responsibility that in my purchasing the ring, the ring should be able to stand up to daily wear, and as it has shown otherwise, I think its the store's job to fix the problem. But, in your opinion, should the work that the store does to make the proper design change or even remake the whole ring with a different alloy (i.e. cobalt, irridium) be done for free? If not, how much should be charged for such work? 4) A bit unrelated, but more connected with convenience, but, they have taken one measurement of my girls ring finger already, is it necessary to take one again before they start their adjustment work? Much thanks again.. Cheers, Jesse On Jul 17, 2:23 pm, "Peter W.. Rowe," wrote: On Mon, 16 Jul 2007 22:07:42 -0700, in rec.crafts.jewelry silverstall wrote: Hi peter I was looking at the image of the ring and unless I looked at the wrong one what I failed to make clear in my post was that this specific design looked reasonably thick and ought not to fall out of shape because of normal wear and tear. Having said that my browser/ screen resolution is widenening images so to me the shank looks a lot wider than it probably is. You of course right in saying the stone need not be removed however I was assuming they would not have used a laser welder. Personally I find it too difficult with such high heat avoiding the stone and I guess as a silversmith I am just used to having always to remove the stones. I take your point about the hardness - maybe its just the few platinum rings I have worked with that were difficult to reshape. The thing with platinum that fools people sometimes, is just how easily bent and dented it can sometimes be, when fully annealed. It's not so much just that it's soft, it's that it's a totally "dead" metal, in that it doesn't spring back at all when bent more than a little. Even sterling, fully annealed, springs back more, though it takes less force to bend it. Now, couple that possibility with the design of the setting, and what becomes possible is that any bending out of round of the shank can pull those side arms out of position, altering the tension on the stone, and thus loosening it. It's true that for most examples of this ring, with most wearers, it's thick enough, or looks it, to withstand easy bending. But people vary a lot, and some people just need heavier rings in platinum than one might expect, even without any sort of abuse or abnormal event. Clearly, the fact that the ring bent out of shape should not be considered just normal and to be tolerated. But it's less clear just why this happened, or what's to blame. Anyway one looks at it, though, the store should find some sort of solution to protect the stone. My own suggestion would be to fit an undergallery jump ring into the setting. This would be a wire ring slightly smaller than the diamond diameter, on which the stone would actually sit, clamped down onto it by the rest of the setting. That undergallery would serve to reinforce the setting as a whole, and isolate it mechanically from any deformation of the shank, so even if the shank gets bent, the stone stays secure. Such an undergallery, while visible from the side, can still be made fairly unobtrusive, and would make the whole setting much stronger. Since it's channel set, fitting this in by traditional means is a little trickier than with prongs, but is doable. For me, it would be easy, since I'd laser weld it in place right under the stone without removing the stone at all. With a torch, the stone would have to come out. As to diamonds coming out for working on platinum, though, the fact that platinum is usually welded with a sharp hot flame, working quite quickly, so the heat is quite localized to the weld area, coupled with platinum's low thermal conductivity (much much less than silver) means that even though the weld is almost white hot, you could have diamonds only a few millimeters away, depending on the thickness of the metal being welded, and they'd still be safe, IF you used proper heat sinking between the stone and the weld. A plain cross lock tweezer on the platinum at that point would be enough to block that heat transfer sufficiently. Of course, the usual practice of having the diamond very clean, and then coating it with a good coating of boric acid to protect it, is still needed. When doing sizings, where one usually is working on the back of the shank, with the stone in front, even careful heat sinking isn't needed. The stone simply won't get all that hot that far away. Silversmiths who're used to the thermal conductivity of silver are often totally unprepared for just how little even gold, not to mention platinum, conducts heat away from a joint. It really does mean different rules apply... cheers Peter |
#17
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Need Help -- lost and found diamond -- defective ring?
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#18
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Need Help -- lost and found diamond -- defective ring?
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