Hello guys!!
I hope you’re all doing well. My name is Ali Alansari and I’m from Bahrain. I’m not a jeweller or in the industry. However, I have a jewellery related question which is why I joined the forum!! I’ve been reading and reading and now it’s finally time to join! Ha!
I recently got married and while my wife is very happy with the ring she inherited from my mother, I still don’t have a ring!
I’ve never like plain wedding bands. I always fancied something with a cabochon.
After a lot of searching I ended up getting a gorgeous pink spinel cabochon which I want to be set in platinum in a signet ring style setting. For reference purposes, the cabochon is 13mm×11mm and my ring size is approximately 62.
The jeweller I’ve contacted regarding the commission has presented me with three manufacturing options: cast platinum (least expensive); hand forged platinum (most expensive); half cast and half forged platinum (middle price).
Obviously hand forged offers better strength but it’s almost double the price of the cast ring!!
Cast platinum is a bit risky from what I’ve read on the internet. It tends to be porous and shows imperfections.
Having voiced my concerns to the master goldsmith, he was touched by my love of handmade objects and proposed a third option: a platinum ring that’s initially cast and subsequently hammered and finished by hand.
Apparently this option offers the best of both worlds and is much more reasonably priced. He mentioned the technique is called überschmieden in German.
I was hoping to get your professional opinion on this third option.
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Can a cast ring be later forged by hand to increase strength and eliminate porosity?
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If not by mechanical means such as hammering, can cast platinum be improved and hardened using heat treatment techniques?
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Given your experience in manufacturing, which option of the three would you guys recommend?
Thank you guys so much for your help and understanding. Looking forward to hearing from you soon.
Kindest regards.
Ali
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Welcome! I’m curious to learn what people think about this. Sadly I’m not much help on this myself
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Thank you so much my brother. I’m looking forward to reading the answers of our fellow forum members!
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There is a big difference between how a handmade piece is designed vs a lost-wax (cast) piece. When you make a piece in wax, you can use all available computer aided design tools to create the wax. This makes for intricate details. A handmade, or “forged” as you call it, involves fabricating the ring by working the metal. It is harder to do, and involves more craftsmanship and labor. The design of a hand-forged ring will probably be simpler than a cast ring. It is also difficult to get the details that a lost-wax cast piece has, but a simple signet ring could be cast or forged. As far as durability, both are very solid. One is not inferior to the other, they are both quite strong, the strongest of the precious metals.
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Thanks for the insight! What about the other technique I mention? Is forging/hammering a ring after it’s been cast common practice?
My husband and I are old school gold and platinum smiths. We learned traditional hand fabrication techniques from master craftsmen who learned between WWI and WWII. For about 6 years my husband Timothy Green worked at a platinum foundry that cast platinum. I would have no problem at all to recommend that you could have the band cast a few sizes too small and then have it hammered up on a steel mandrel to size. Forging cast metal lines up the molecules and makes it harder. It’s basically just like casting an ingot and then forging and rolling into sturdy bar stock. We made fancy wedding rings for each other but because of the nature of working in our shop we made plain 24 kt gold bands for ourselves. We call the our “Beater Bands”. 24 kt gold is super soft as cast. So we made our rings several sizes too small and hammered them up to our finger sizes. They are pretty stiff. So go for the compromise.
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Oh and send photos when it’s done. I’m looking forward to seeing the pink spinel and platinum.
Oh Lord!! Jo!! Thank you so much for your input! You’re in fact the very person whose opinion I’ve been anticipating most.
While reading about platinum and forging vs casting, I had come across a nunber of your posts on this forum. You and your husband seem to be AMAZING traditional goldsmiths that have the added bonus of being casting experts!!
I regard your opinion very highly!
I just have some additional technical questions about ring casting if that’s alright.
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Is it standard practice for cast rings to be heat treated after casting? If so, what are the treatments?
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Are hand forged rings heat treated as well? Would that benefit them or make them even stronger?
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For the compromise technique that you have mentioned (casting in smaller size and hammering), is the ring hammered cold or does it have to be heated and then hammered to the correct size?
Thank you so much for your reply and invaluable advice!
God bless
The platinum foundry that my husband Tim worked at uses a process called called HIP. Hot Isostatic Pressing. It’s a machine that places castings inside under extreme heat and pressure in an argon atmosphere This collapses any internal imperfections. Hot Isostatic Pressing Heat alone will not fix porosity or imperfections. It needs the 25000 PSI. See the images attached in the link.
-Jo
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Did your husband work at TechForm? I’m familiar with their work and reputation!!
Jo…This is a cool discussion. How is the 25,000 PSI created? Is it air pressure or hydraulic? Thanks…Rob
Jo, I’m curious. Would cold working and hammering a ring after it’s been cast mimic the effect of the 25,000 PSI?
It’s really interesting. Swordsmiths of yesteryear used an approach very similar to the “casting+hammering” technique in order to produce high quality blades. The molten metal would be cast into a mould similar in shape to a blade and subsequently hammered repeatedly.
Yes. He retired from there after 6 years when he turned 65 and became eligible for Medicare last December. As self employed folks when you get over 50 the health ins costs get astronomical. Now he’s back in our studio full time-ish. And yes they do a really great job. Pay for the extra HIP treatment. It costs an extra $40.00 They also offer a new alloy by Hover and Strong called 950 Hard Platinum. It’s a bit more $. It’s pretty hard. 180HV annealed. That said, all cast plat should have the HIP process.
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No. HIP collapses internal imperfections only.
What about hammering and cold working a platinum ring? Would that eliminate both onner and outer imperfections?
Thanks dear. And I apologise for the overwhelming amount of questions. It’s just that both your husband and yourself are a treasure trove of knowledge!!!
Thanks again!