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Granulated Silver Earrings by Sandra Buchholz Advanced project. These earrings have a granulated pattern on the surface and a small stone set in the center. Granulation is the process of fusing tiny metal spheres of silver or gold in a decorative pattern to a surface of the same metal. It is an ancient technique that produces a beautiful, delicate effect. For a gold granulation workshop, check out June 2001's Granulated Dome with Repousse Bail |
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A distinction of granulated jewelry is that connections are fused instead of soldered. Fusing involves raising the temperature of both the back sheet and the granules to the point at which they melt just enough so that they will adhere permanently to one another. This is a very delicate operation. If the correct temperature is not reached, the items to be fused will not hold properly, necessitating the reheating of the whole piece, in order to replace them. If the temperature gets too high too fast, meltdown can occur, which is irreversible. Therefore, lots of patience is needed and the piece needs to be brought to the appropriate temperature very slowly. Fusing occurs at a higher temperature than soldering -- it will undo any solders you have done previously on the piece. As both processes are used in making these earrings, it is important that you do not solder when fusing is required. Read the instructions before starting out to get an overview of what you will be doing. STEP 1. General process for placing items for fusing.
Prepare a mixture of 10 drops of water, 2 drops of Hide glue, and 3 drops of liquid flux. This will be applied sparingly to all surfaces to be fused, and act as temporary glue to hold the items in place until they are heated. Once heated, the hide glue burns off and the items are no longer glued down. Turn up a comer of the backsheet with small pliers, so that it can be easily grasped with tweezers. This will enable you to move it easily and without tipping it. This piece will eventually be cut off. Using the 000 sable brush, apply the mixture to the item to be fused before placing it on the backsheet. This mixture is also water soluble, so if you want to make a correction in placement, flood it with a small amount of water. This will dissolve the glue and you will be able to move the piece.
STEP 2. As it heats up, the hide glue will begin to turn dark brown (don't worry; it will burn off). Place the earring in the kiln and cover it with the metal cap while you light the torch. Check it fairly quickly to see if all the glue has burned off. Once the glue has burned off, the earring will look radiantly silver, but the objects on top of the backsheet are all unglued and loose, so don't jar the kiln or move anything too suddenly.
STEP 3. General information for fusing. Start to heat the entire piece with a slow, circular motion around the outside of the periphery of the backsheet. This will build up a cone of heat around and above the entire piece, allowing it all to rise to the same temperature at the same time, while the kiln is providing the necessary bottom heat. When the outer edge of the silver begins to show signs of shimmering, pass the tip of the flame closer into the area you wish to fuse. Use a gentle, sweeping motion and do not concentrate the flame in any one spot. As you do this you will actually see the surface of the silver shine and run -- a little like solder does -- and you can usually see the surface change right up to the edge that needs to be fused. Withdraw the heat quickly and turn off the torch. Give the piece a few seconds to cool, then quench in cold water. Test the parts that were fused with a sharp, pointed instrument (tweezers, etc.) to see if they have been completely fused. If some areas are still unfused repeat the whole procedure over again as many times as necessary to get everything solidly fused.
STEP 4. Preparing the back sheet. Sand the backsheet, then apply tripoli, eliminating all scratches. Clean it very well, making sure to remove all traces of the tripoli. From here on in, try not to get fingerprints on it. Any extraneous material on the surface of the metal, such as fingerprints or polish, can interfere with the fusing process. Coat the back of the backsheet with ochre to prevent overheating the piece when fusing takes place.
STEP 5. Preparing and fusing the bezel. STEP 6. STEP 7. Gently apply ochre to the very top rim of the bezel. Since you will probably heat and reheat the piece several times, this will help prevent the bezel from accidentally burning around the top.
STEP 9. Preparing and fusing the decorative wires. Using the 22-gauge round wire, shape a ring that will fit exactly around the bezel. Fuse the ends together and reshape it on a mandrel to be sure it is perfectly round. Check the fit of the ring around the bezel. To fuse properly, it must be an exact fit, leaving no spaces either around the bezel or between it and the backsheet. If necessary, flatten the ring between 2 steel blocks. Place it over the bezel and fuse it to the backsheet.
Paste it down temporarily with the Hide Glue mixture as described in the section on fusing. Fuse the larger ring to the backsheet. STEP 11. Granulation. Granules can be either bought or made. The obvious advantage to buying granules is that you save a great deal of time that you would otherwise spend making them, and that they will be uniform in size. Uniformity is important because it affects the final look of the design. The downside is that they are expensive, and usually need to be purchased in larger quantities than you would need for one project. For this project you would need about 3 pennyweights (dwt.) of fine silver granules. They generally come in 3 sizes: large (.032), medium (.024), and small (.016) The large size was used for these earrings. The main advantage to making your own granules is cost. After some experimenting, you can also make granules of different sizes, and find the size that suits your work better than purchased ones. You can also make as many as you need, as you need them. Experimentation and practice is helpful. Granules are made by coiling fine silver wire around a pin stem or needle that is used as a mandrel. The final size is a variable of the thickness of the wire, the diameter of the mandrel that is used for coiling the wire, and the point on the curve of the coil where the wire is cut. To maintain uniformity, the wire should be cut at precisely the same point in the curve each time. STEP 12. Hint: It is helpful to carve a ridge around the top of the charcoal block. This provides a channel for the granules to roll into and makes them easy to retrieve. STEP 13. Once you have found the correct size continue to make granules until you have as many as you need. As mentioned before, you don't need to do them all at once; make them up in batches as you need them. STEP 14. Placing the granules.
STEP 16. To start the second triangle, skip 1 granule space, then repeat the procedure. The pattern will look different depending on where you place each triangle. Try to be consistent in how far apart they are.
Set the earrings aside and let them air dry for about 5 to 10 minutes. STEP 18. Fusing the granules. When the glue mixture turns dark brown (don't get alarmed) carefully lift off the backsheet holding it perfectly horizontal so as not to disturb the granules, and place it in the hottest part of the kiln (usually there is a bright hot spot which is visible). STEP 19. Use the same technique as described before. Hold the flame at right angles to the piece, and allow only the feathery tip to come in contact with the metal. Start by slowly describing a circle around the outside of the piece, to allow the heat to build up evenly while the kiln provides bottom heat. Every once in awhile, pass the tip of the flame over the metal piece itself in a kind of sweeping, swooping motion that does not concentrate the heat in any one place. Don't rush this process either! Work slowly and methodically, heating around, and then over the piece. STEP 20. STEP 21. Hint: Until you have experience in determining whether fusing has taken place while the piece is hot, it is probably better to underestimate the time and then repeat the process if necessary. If the piece gets overheated, the granules will melt and the piece will not be salvageable.
Remove the ochre from the back of the piece by painting it with paste flux and heating it until the flux becomes shiny. While hot, plunge it in pickle, then rinse and use a brass brush to clean off residual ochre. This may have to be repeated a few times. To bring up the fine silver and give the piece a soft look, coat it with paste flux, heat the flux to a shine and pickle, then use a brass brush to bring out the sheen. Rouge can also be used on the granulated surface, but not tripoli or any abrasive -- they will erode the granules. Sand the back of the piece and polish to a satisfactory shine. Solder the posts with medium solder. This should be the last operation before setting the stones.
For an excellent article on high-karat gold granulation, see "Granulation" by Cecelia Bauer in the Hoover and Strong catalog, 1996-1997, p 21. For an excellent article on sterling silver granulation, see "Sterling Granulation" by John Cogswell in Metals Technic, Brynmorgen Press, 1992, p.3.
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