How To
How To Use Aura 22 Accent Paint On Your PMC Designs
See how to easily add touches of 22 karat gold to your PMC and other silver designs with Aura 22 accent paint. The result is a permanent, natural, fluid-looking layer of gold that is substantially thicker than electroplating.
• Because Aura 22 is relatively thick, you can easily control your application, accenting your design where and how you like.
• Aura 22 is especially effective on heavily textured surfaces and in areas normally difficult to accent.
Please Note: Aura 22 must be applied to fine silver or gold. To use it on sterling pieces, you must first depletion-gild the metal to create a layer of fine silver. Information on this process is available from Rio Grande.
Each one-gram jar of Aura 22 will accent approximately 20–30 small pieces, depending on the amount of accenting you wish to do.
Step 1
Be sure that your workpiece is fine silver. If the piece is sterling silver, you must depletion-gild it to bring a layer of fine silver to the surface. IMPORTANT: Aura 22 will not adhere to sterling silver without this step.
Step 2
Make sure that your silver workpiece is clean and free of any oil, fingerprints or debris. The surface should be "kiln white" or "pickle white." Aura 22 will not adhere to polished surfaces.
Step 3
Aura 22 should have the consistency of nail polish, thick but easily spreadable. If the solution is dried out or too thick, follow the instructions on the rehydrating agent included with your Aura 22 to restore the correct consistency. Be careful to follow the instructions carefully to avoid ruining the consistency or dulling the color of the Aura 22.
Step 4
Apply the Aura 22 to your silver piece using a clean, dry paint brush or rubber-tipped tool. Apply the solution in even layers, allowing each layer to dry for 15 minutes between applications. Usually 2 to 3 layers deliver the best results. Allow the piece to dry thoroughly after the final layer is applied; the color when dry should be a dark gold. Please Note: Any moisture left between layers will become steam during firing and will cause blistering and/or poor adhesion.
Step 5
TIP: After applying Aura 22, clean your paint brush by swirling it in a small jar of water. Keep a separate, dedicated jar for this purpose to capture the gold from the brush. When there is noticeable sediment in the bottom of the jar, allow the water to mostly evaporate and return the semi-dry gold residue to the Aura 22 jar.
Step 6
Fire the piece, either in a kiln, at 850°F (450°C) for 30 mins., or using a torch to fuse the metals. The torch method is the most effective because it allows you to watch your progress and burnish the piece as soon as the firing is complete. Any simple butane-fueled, hand-held torch can be used for this purpose. Remember to take every precaution for safety when working with kilns, torches and hot metal.
Step 7
To torch-fire, move the torch constantly around the accent painted on your workpiece. You will notice the binder in the Aura 22 solution burning off first (the fumes from this are completely non-toxic and present no health hazard to you or your shop).
Step 8
Shortly after the binder burns away, the piece will begin to glow a pale red. When this happens, watch the accent on your workpiece while continuing to move the flame over and around it. Before long, the Aura 22 will change color from the dark gold to a pale yellow. As soon as this color change happens, shut off your torch—the silver piece SHOULD NOT be heated beyond the pale red color.
Step 9
Whether you've used a torch or a kiln, immediately after firing, while the work piece is still hot, the Aura 22 MUST BE burnished to complete the fusion process and prevent the gold layer from flaking off. Burnish well, covering every part of your painted accent. DO NOT QUENCH THE WORKPIECE PRIOR TO BURNISHING!
Step 10
Once the piece has cooled, complete the workpiece with the desired finish. Pieces can be left burnished or can be further finished with tumbling, brushing or polishing just like any piece of gold to produce the desired final finish.
How To Use Cork Clay
Learn how to use cork clay to create hollow beads and other forms with metal clay. Cork clay is useful as a core for making hollow objects with Precious Metal Clay®. The clay burns out cleanly when fired with PMC.
Cork clay is made of cork powder, carboxymethylcellulose (non-toxic), water, anti-mold agent and fungicide.
Helpful Hints
• Wash your hands before and after handling cork clay.
• Keep the unused portion of cork clay tightly wrapped in plastic wrap to prevent the material from drying out. Please note: Once cork clay is dry, it cannot be re-hydrated.
• Store your cork clay at room temperature.
• Always fire the material in a well-ventilated area. Cork clay produces smoke as it burns.
Step 1
Form a shape with cork clay.
Step 2
If desired, insert a toothpick or wood skewer into the cork clay form so that you will have a handle to hold later as you apply the PMC® to the shape. If you would like a hole in your finished PMC piece for stringing, penetrate the form from end to end with the toothpick or skewer.
Step 3
Allow the cork clay form to air dry completely—moisture in the material will produce steam when fired and could damage your project. The drying process usually takes at least 24 hours and the material will be hard when completely dry.
Step 4
Once the cork clay has dried, you can drill, sand or carve it.
Step 5
Apply PMC clay, or PMC slip to the cork clay. Always leave a hole in the clay to allow for burnout of the cork clay; you can patch the hole and re-fire if you do not want it in your finished piece.
Step 6
If your piece is larger than 1" in diameter and you are planning to fire at 1650°F for two hours, lower your ramp speed to 1500°F to allow the cork clay to burn out a bit slower. This will prevent the possibility of a flash burn of the cork clay. Caution: Do not open the kiln during the firing process. Oxygen could cause the cork clay to ignite, injuring anyone near the kiln.
How To Finish PMC Designs
You have several options when it comes to finishing your PMC designs. Get a quick view of the various hand and machine finishing options.
HAND FINISHING:
The simplest way to finish PMC® is to use your hands and some good, old-fashioned elbow grease.
• Polishing papers are rated in grits. The grit tells you how many particles per square inch the paper has; the lower the number, the more coarse the paper.
• Begin with a coarse paper (about 400-grit) and graduate to increasingly finer papers until you achieve the finish you want. Change the direction of the stroke when you change grits to see when the marks from the previous paper have been removed. Use adequate pressure so each grit paper can work effectively.
• A hand burnisher can be an alternative to using sanding paper. After firing, run the burnisher along the surface of the metal, moving in the same direction for each stroke, and overlapping strokes to avoid leaving drag marks.
MECHANICAL FINISHING:
Use a mechanical polisher, such as a flex shaft, to create textures with less time and effort. They hold a variety of attachments, offering a range of application options. Most polishers accept a range of accessories.
• A foot-pedal control is an important accessory; it keeps your hands free to work and allow you to control the motor speed as you work, changing speeds as needed for each piece.
• A flex shaft reduces hand fatigue and strain; it allows you to hang the motor from a stand and work with a smaller, lighter handpiece.
• Mounted motors give you the convenience of hands-free operation and accept larger attachments; they are ideal for large or flat pieces and for higher production needs.
How To Set Temperature-Sensitive Stones into Original PMC
Courtesy of the PMC Guild archives, these instructions from Tim McCreight show you how to set temperature-sensitive stones into your designs made using original silver PMC.
One of the really cool things about PMC is the way certain stones can be fired into place. Of course this only works with gems that can tolerate the relatively high temperatures of the firing process. What about natural gems like jade, turquoise, and agates? Besides soldering on bezels after firing, is there any way to set these in original silver PMC? Yes! The trick is to use a plug of high-temperature material to hold a place for the stone. Let’s see how this will work . . .
For our purposes, imagine an oval turquoise cabochon that measures 10 x 14mm. This stone would be absolutely destroyed by the firing process, so some alternative is needed.
Step 1
I’ll need to make a plug of some material that will stand up to the sintering temperature of 900°C (1650°F). This could be a piece of fire brick, investment (jeweler’s plaster), or potter’s clay. Whichever you choose, create a plug that has the same "footprint" as the stone, in this case a 10 x 14mm oval. I use a plastic template or simply trace around the form, then I use files to carve the plug.
Step 2
Notice that the sides of the plug are straight, and that it is about twice as tall as the stone. After some experience with original silver PMC, most people get a sense of the shrinkage and develop a knack for understanding how much the size will change. To help with this, try using a copier with reduction settings. Make a sketch of the piece the size you intend to make it and set the copier to about 60%. It’s also possible, if you are gentle, to set the actual piece onto a copier and do the same thing. The alternate version works well, too: Make a drawing of the piece the size you want it when finished, then set the copier to 140%. This will tell you what size you should make the PMC original.
Step 3
If you don’t want to take the time to get to a copier (I’m usually in too much of a hurry to get on with my work), you can make a quick sketch and do some simple math. In the case of this example, for instance, I multiply the dimensions of the stone by .4 (40%) and come up with 14 by 20 as the pre-fired size that will be needed to contain the turquoise. I make a quick sketch on a piece of scrap paper to help me visualize the starting bezel.
I build a rim of clay roughly this size from fresh PMC and attach it to my work.
Step 4
My educated guess is that this rim will shrink down to fit the stone. To ensure this, however, I set my plug in the center of the oval; no attachment is necessary. When the PMC shrinks in firing, it will close in on the plug and stop there. Even if my guess was off by a little, the plug will stop the PMC at exactly the correct size.
After firing, I lift the plug out to reveal a straight-walled compartment that is a perfect fit for the stone! I finish the piece in the usual way and complete all soldering and polishing, then lay the stone into place. I use the cut-off handle of a toothbrush to press the bezel down onto the stone, working alternately around the stone until the wall lays down smoothly. I achieve final shaping with a small file and polish with a burnisher.
How To Solder On PMC: Frequently Asked Questions
Soldering is one of the most challenging and rewarding techniques in metalwork. While it is possible to work with PMC without soldering, we believe most people find that the ability to solder significantly expands your design possibilities and vastly broadens your creative opportunities. Soldering is a complex topic that you’re going to learn best through experience, but getting a grip on the basics is a great place to start and will intensify the value of your experience. Read more in this FAQ from Tim McCreight, courtesy of the PMC Guild archives.
Phase 1
Q: How is soldering on PMC different from soldering on sterling?
A: In many ways there is no difference. Solder flows at specific temperatures
and under specific conditions regardless of the metals being joined.
The biggest difference lies in reading the temperature of the metal as it is heated. Sterling goes through a specific and clear sequence of color changes. Most people who have been soldering sterling for a long time are not even aware of how closely they read these colors--at least not until they work with fine silver. PMC, like any other forms of fine silver, remains white right up to soldering temperature. Where sterling sends out signals, fine silver remains uncommunicative. The best solution (other than a lot of practice) is to work in dim lighting so that the subtle red glow of fine silver is easier to see.
Phase 2
Q: What kind of solder should I use?
A: Silver solder, properly called "silver brazing alloy" makes its joins inside
the structure of the metal and is therefore much stronger than low temperature
solders that work on the surface. Rather than say this is what you should use, I’d say it is important to design for the solder you choose.
If you use a low-temp solder (say 750°F), it is important to provide enough surface contact to support the joint.
Brazing alloys (often called hard solders) are preferred, but they can be a little more difficult to learn. Worth it, in my opinion, not only for strength but because they offer the best color match. Also, once a piece has been joined with a low-temp solder, it cannot be soldered with silver solder, which then makes repairs more challenging.
Phase 3
Q: What flux do I use?
A: This is an easy one--you must use a flux that is active at the temperature at which the solder flows. Flux is a material, typically liquid or paste, that inhibits the formation of oxides on metal as it is heated. The shorthand way to say this is that flux keeps the metal clean. The best way to ensure that you are using the proper flux is to purchase the solder and flux at the same time. Some low-temp solders are sold with flux attached or even built into the solder as a chemical core within the wire. When in doubt, put a little flux and solder on a bit of scrap and heat it up. If the solder flows into a puddle, the flux is doing its job.
Phase 4
Q: What about easy, medium, and hard solders?
A: This refers to three grades of silver brazing alloy: each melts at a slightly different temperature. The trick in brazing is that the entire object needs to be heated to high temperatures. When many joints are being made in close proximity (as in making jewelry), there is a risk that early joints will heat up and let go as later joints are being made. To prevent this, start with a high-temperature alloy (hard solder) and work down to easy so that successive joints are made at lower temperatures, protecting the joints made before. When using only one type, I recommend hard solder because it is easier to control.
Phase 5
Q: Do I need a torch?
A: Yes, pretty much. Some low-temp solders could be melted on some hotplates or on a kitchen stove, but these devices are very difficult to control. Kilns are used industrially but, for practical purposes, a torch works best for jewelry-scale work. For most applications, even a small butane torch will be sufficient.
Phase 6
Q: Do I need to burnish the area being soldered?
A: This is recommended for original PMC but not needed for PMC+ or PMC3 (not that it does any harm). Note, though, that mechanical burnishing in a tumbler is not recommended because the soap involved in that process will inhibit solder flow.
Phase 7
Q: Do I need pickle for PMC?
A: No. Pickle is a chemical that removes oxides and the glassy residue left from some high-temp fluxes. The oxides that form on fine silver do not require pickle, and flux residue can be removed with hot water.
Phase 8
Q: Why is there an "L" in solder?
A: The word comes from the Latin "solidus" and simply retained the "l" over time. Listen to the first syllable; British English retains the "l" sound, pronouncing the word as "sawl-der."
Q & A With Tim McCreight: Defining Fine Silver, and the Importance of Time and Temperature in Firing PMC
Courtesy of the PMC Guild archives! PMC expert Tim McCreight explains fine silver and the importance of PMC firing time and temperature in this Q & A.
Q: I sometimes see reference to ‘fine’ silver . . . what’s that?
A: In the precious metals world, the word “fine” means pure. Fine silver is pure silver—nothing more. The numeric designation ".999" is sometimes also given, a scientific way of abbreviating the fact that nine hundred and ninety-nine parts per thousand (or 99.9%) is pure silver. Why not 100%? Well, the removal of the remaining trace elements is prohibitively expensive.
Q: I understand that I should fire silver PMC at 900°C/1650°F for two hours. Which is more important, the time or the temperature?
A: Both the right time and temperature are important in achieving fully sintered or bonded PMC, and there is no doubt that the best results are achieved by following the manufacturer’s directions: “Fire at 900°C for 2 hours.” To answer your question, though, temperature is more important. If you heat a piece of silver PMC to three-fourths of the correct temperature and hold it there for many hours the result will be a crumbly material. Imagine trying to boil water at 150°—no matter how long you wait, it just ain’t gonna bubble! If you heat your PMC sample to the correct temperature for an hour, you’ll achieve a material that polishes pretty well and feels like silver, but is not as strong as it would be if fully "cooked."
Note: This Q & A applies only to Original PMC.
Instructions
Getting your feet wet with PMC®? This guide is your full introduction to the formulas, tools and techniques for working with precious metal clay.
This short guide introduces precious metal clay and its working properties.
Use this handy chart to compare the post-firing strengths of PMC, PMC+ and PMC3. Courtesy of the PMC Guild archives.
MSDS
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