This was a really fun project. At my work we're often brought older jewelry pieces to repair and modify and the owner of this vintage Opal ring wanted to keep part of her original ring and incorporate it into an entirely new design, which was a neat challenge. By creating a 3D model it was possible to show the owner how a new ring could be created while keeping the main design element of her vintage Opal and Sapphire ring, which was very sentimental to her.
Step 1: Creating the 3D Model
There are a few different methods of creating a ring like this. You can carve a wax by hand (difficult for this design), hand fabricate it from sheet and wire (expensive and time consuming), or create a 3D model and have it printed and cast, which was the most practical approach with this design. The other benefit of creating a 3D model is that it allowed the client to view the design before the casting was created.
When creating the model measurements were taken of the top of the client's old ring and a new ring was built around it. The top of the old ring would be treated as an insert in the top of the new ring. A border was added around the top section in order to add additional stones. Once the border was added the under wire supports were added, followed by the ring shank. The top section was then removed, leaving just the border and then prongs were added down the sides of the ring shank for setting additional stones.
Step 2: Tools and Materials
I covered in great detail most all of the tools that jewelers use in this instructable so please refer to that for learning about all of the tools and how they are used. I also included links in each section to specific tools used in the making of this ring. If there are ever any questions about tools or procedures please don't hesitate to ask!
One thing I am often asked about are metal alloys used in jewelry manufacturing. There are benefits and drawbacks to all precious metals. This particular ring was made in 14K white Gold. For white alloys the choices are Platinum, Palladium, white Gold and Sterling Silver.
Platinum is the strongest of all precious metals- unfortunately it's also the most expensive. There are typically three Platinum alloys used- 95/5 Platinum/Ruthenium, 95/5 Platinum/Cobalt and 90/10 Platinum/Iridium. Of the two 95% pure alloys Platinum/Ruthenium is what I most commonly use for castings. Platinum/Cobalt is used by many large manufacturers because it flows better than Platinum/Ruthenium so it can capture detail a bit better but it's not a terribly friendly alloy to work with as it reacts to Oxygen when heated- this makes sizing rings later more difficult. It also oxidizes (unlike the other Platinum alloys) so it doesn't hold a finish as well as other Platinum alloys. Platinum/Iridium is more often used when hand fabricating jewelry as it lends itself very well to rolling, forming and drawing processes. Much of the Platinum jewelry from the Art Deco period was made with this alloy. It casts fine, but not quite as well as Platinum/Ruthenium. Ruthenium and Iridium alloys will not oxidize and they hold a finish very well. Platinum also has greater density than other precious metals (it's over twice the weight of Sterling Silver) so large jewelery pieces can get rather heavy. For a jewelry piece to be marked Platinum or Plat is has to be a 95% pure alloy.
Palladium is in the same family of metals as Platinum and most Palladium alloys are 95% pure alloys. Palladium has the advantage of a very low density for an alloy of high purity- it's right in between Sterling Silver and Gold. The advantage to this is that if you have a large/chunky design for a necklace or ring you can get a finish that is similar to Platinum but at a much lower weight. Palladium typically costs slightly higher than Gold but nowhere near the price of Platinum. The biggest disadvantage to Palladium is that it is significantly softer than Gold or Platinum so filligree or delicate designs with thin prongs are really not suited to this alloy- its best use is in more solid designs with bezel settings, channel settings or flush settings. Palladium and Platinum alloys can be very tricky to cast as they really should be cast in an inert environment. Microporosity (seen as very, very tiny pinholes or a milky surface) can be very common if these alloys are not cast properly. Palladium has a slightly more grayish color than Platinum and Sterling Silver. Palladium jewelry is typically stamped or marked 950 Pd.
Palladium and Platinum are often referred to as "dead" metals- when you push a prong down on a stone it tends to stay there. By contrast white Gold is pretty springy (it has a fair bit of memory) so when you push a prong down it sometimes has a tendency to spring back so you need to check and make sure your stones are really secure.
White Gold is a common multipurpose alloy that works well for all kinds of designs due to it's good strength, reasonable weight and casting properties. It does not lend itself to hand fabrication as well as Platinum as it work hardens rather quickly. White Gold is a bit trickier to cast than yellow Gold (which is very forgiving) but it can be done with any small centrifugal casting machine. Nickel is typically what gives white Gold its white color (sometimes it is also alloyed with Palladium or Silver) and as such it can cause some people to have a skin reaction and the white Gold alloy will also oxidize and turn more yellow over time. The common solution to this is Rhodium plating. Most all production white Gold jewelry is Rhodium plated- this is what gives it a bright white finish as Rhodium is brighter than either Platinum or Silver. One other thing I will mention is do not wear white Gold jewelry in a hot tub as the chemicals will attack the alloy and cause corrosion cracking. Gold jewelry is usually stamped or marked 14K or 585 for 14K Gold alloys and 18K or 750 for 18K Gold alloys.
The last white precious metal alloy commonly used in jewelry manufacturing is Sterling Silver. Sterling Silver has a very low density and is much lower cost than Gold. It is a very soft alloy and much like Palladium should be used in designs that favor bezel, channel setting and bead setting for stones. Thin tall prongs will have a difficult time holding stones securely. Silver will oxidize rapidly and polished finishes will not last as long as other white alloys. Sterling Silver is extremely forgiving to cast and it is very easy to form and finish. Whenever someone is starting out making their own jewelry I always recommend using Sterling Silver because of the low cost and how forgiving it is to work with.Sterling Silver jewelry is typically stamped or marked 925 or Sterling.
Step 3: Cleaning Up the Casting
Once the 3D model was approved the design files were sent to a facility that prints the model and then casts it using the lost wax investment casting process. It typically takes around a week or so to receive the raw casting from the caster. For Gold and Silver casting of 3D models Best Cast does a really nice job.
Once the casting is received I go over it very carefully to check for any defects. Next the casting sprues are ground off and those areas are filed and sanded smooth. Then I clean up the inside of the ring, making sure it is round and the ring size is correct. The sides of the ring are sanded flat with a sanding stick and then the rough surfaces of the raw casting are smoothed using abrasive wheels with a rotary tool. Once I'm happy with how the raw casting looks I'll give it a light polish using a tripoli compound as any surface defects will immediately show up and you want to take care of that before setting any stones.
Step 4: Setting Stones
Next I get the ring prepped for setting stones. The process is the same as what I showed here but on this ring it was quite a bit simpler as small prongs were incorporated into the casting so there wasn't nearly the same degree of engraving/cutting work involved.
With this setting I used a small drill to drill a relief for the bottom of each stone. Next a straight setting burr was used to cut the seats for the stones. After all of the stone seats were cut I used a stainless steel brush in my rotary tool to remove any small bits of metal leftover from cutting the seats. Each stone was then placed in its seat and the tiny prongs were forced down over the stone using a beading tool.
I set the smaller stones in the border at the top of the ring first and then set the stones down the sides of the ring shank.
Step 5: Polishing and Plating
Once the stones were set the ring was given a final polish using a rouge compound and this was followed by plating the ring in a Rhodium solution. Rhodium plating involves first cleaning the ring in an electroclean solution followed by a water rinse and then the Rhodium bath, followed by another water rinse. Both the electrocleaning and Rhodium bath are done at around 5V using a rectifier with a time of one minute for the electrocleaning and around thirty seconds for the Rhodium bath. After the ring is removed from the Rhodium bath it has a very bright white finish.
When discussing the design with the owner it was decided to plate the small curved wires on the underside of the ring yellow in order to have the design tie in with the top of the old ring. The wires could have been made from yellow Gold wire and soldered in but that would have added significantly more cost to the ring due to the amount of labor involved.
In order to plate the wire section the rest of the ring was coated with finger nail polish and allowed to dry. Only the areas that were to be plated yellow Gold were left exposed. I personally prefer red finger nail polish as it tends to be less runny and it's easier to see but all I had in the shop was yellow so that's what I used. :)
The yellow Gold plating process is exactly the same as the Rhodium plating process and I was very happy to see it turned out perfect the first time. If I had done a poor job masking the ring with the finger nail polish the yellow Gold plating would have gone in the wrong areas and I would have had to remove the plating and repeat the entire polishing, plating and masking process. Once the yellow Gold plating process was complete I soaked the ring in acetone to remove the finger nail polish.
As a side note, there are certain stones and material like Lapis and Pearl that cannot be immersed in plating solutions as they will quickly be ruined. When in doubt always ask the plating solution manufacturer if your material is safe to be plated.
Step 6: Adding in the Final Piece
Now that the new mounting was ready it was time to add the center top from the old ring. The top was carefully cut off the old ring and trimmed to fit the new mounting, making sure to get it centered perfectly and level. Once I was happy with the fit I polished the piece and inserted it into the top of the ring and used a laser welder to weld it to the new ring on the underside of the ring.
The reason I used the laser for this job is that the old ring top had Opals set in it. Removing and resetting the Opals would have been risky since they fracture so easily so it was far less risky to finish the mounting first and then weld the center piece in place. If I didn't have access to a laser welder I would have needed to remove the stones from the center piece, solder it in place and then reset the stones before the ring went through the entire polishing and plating process.
The finished ring was then presented to its very happy owner. I was told she was absolutely thrilled with how the finished ring turned out and that always makes me very happy. I also think it's pretty neat when you can recycle old jewelry and turn it into something new, especially when you can retain the sentimental nature of the original piece.
As always if anyone has any questions about jewelry manufacturing and all of the processes involved please don't hesitate to ask!