Fabricating a Platinum Three Stone Ring
Part II
By Tom Weishaar
1. In part I of this series I showed how I would make this platinum shank. In this article I am going to fabricate the center marquise shaped crown.
2. The center crown for this rather long (13.5 mm) marquise diamond will not be the normal basket style crown. Instead the end chevron prongs will flow in toward the ring shank. This does change the procedure for making the crown. The first place to begin any crown is always with the upper gallery support; everything else builds off that support. In this picture I am measuring off a length of 1.5 mm by 1 mm platinum wire. The wire has been curved to follow the outer profile of the diamond.
3. After marking the midway point on the platinum wire a small notch is filed. The notch will create a weak point at which the wire will bend. I will be bending the wire approximately 150◦ so I will need to anneal it at least once during the bend.
4. The upper gallery support should be 10% smaller than the diamond and it should match the outer contour of the stone perfectly.
Both of the end seams are soldered together using 1700 platinum. I mentioned in the first article, but it bears repeating – please do not use inexpensive or repair solders. You only hurt yourself in the long run.
5. Once the upper gallery support is completed it is time to build the outer two chevron or V-prongs. For this I am using a 3/4 inch section of 3mm square platinum wire. The wire needs to be sliced on its diagonal. I like the slice to be about 4mm then I flip the stock and slice the other side. This way my saw blade does not get a chance to wander.
6. Once the platinum has been halved on the diagonal I like to use my square file to notch it lengthwise. I’ll leave the metal about ¾ of a millimeter thick. I know that Steve Satow has written many articles about customizing tools and pliers. He’s probably
mentioned notching a pair of pliers to hold pieces like this. These pliers have square and round notches – they work great!
7. After notching I tapered my chevron prongs and am now bending them with a pair of shank bending pliers. After this they will be fine sanded and polished.
8. My ceramic soldering block has a series of various sized holes and widths of trenches cut into it. I can usually find one to wedge my parts down into as a makeshift holder for soldering. Since I used 1700 platinum solder for my upper gallery support I’ll drop down to 1600 to solder the chevron prongs on.
9. After soldering my prongs to the upper gallery support I spent a fair amount of time mitering the bottom of my chevrons so that they would straddle the center top portion of my shank. This is one area that if you don’t take your time you’ll get gaps and a pitted solder seam. In the picture the prongs and shank are being soldered together using 1600 platinum solder.
10. In this picture I have slipped the marquise into its crown and am now testing the trilliant to see how it will fit. I have to place side prongs on the marquise, so I want to see where it will be best to position them.
A great tool for fitting prongs into galleries is a Kraus Bur. These burs are long, tapered and have nice aggressive teeth which cut quickly. For holding prongs I like to cut a groove about 1/3 of the prong’s diameter into the gallery support. This groove will increase the surface area between the prong and crown and give me a stronger solder joint.
11. The four side prongs are soldered in place with 1600 platinum solder.
12. This picture of the completed marquise crown will close the second portion of this three-part article. Next time I will be building the two side trilliant crowns and setting the stone. Thank you for following along.
This article first appeared in Bench Magazine http://www.BenchMagazine.com
For more information on Laser welding go to: http://www.PlatinumGuru.com
For weekly tips and articles on Laser welding go to: http://www.BenchMedia.typepad.com/platinumguru