What is metal clay, anyway?
||From Easy Metal Clay:
Hadar Jacobson's Gradient Pendant
How often does a brand-new craft medium come on the scene? Not very--but it's happened to us. Metal clay is a dramatic, new hybrid medium that in some ways is like its parents and in others is like any offspring--displaying a distinct personality all its own.
First appearing about 1990 in Japan and introduced to the U.S. jewelry-making world in 1996 in a limited way, metal clay is now available in many forms and metals and from several manufacturers. Metal clay consists of tiny metal particles suspended in a clay-like, organic binder. You mold and fire it as you would a clay, but when this remarkable material is in the kiln, the binder burns off and the metal particles stick together--leaving behind the clay's form but only the metal's substance. Form a ring out of silver clay and fire it, and you have a silver ring, pure and simple.
Rich textures that once required many hours to produce by hand in jewelry made with metal sheet can now be worked into metal clay in moments. Patterns from found or natural objects can readily be transferred to your jewelry without expensive equipment. Components can be whipped into shape without specialized jewelers tools, then assembled without soldering.
But it's not all about what you don't have to do--it's also about what you can do. You can make large pieces of jewelry that are lighter in weight and more comfortable to wear than those made with sheet because the fired product is less dense, a result of the original separation between metal particles. Because the particles do move together and join, though, the material shrinks after firing--something you need to take into account for sizing and in some cases for durability as well, but also something you can take advantage of when setting stones. Set it up right, and as the metal slowly cools, it closes in around the stone, securing it in place.
You can make jewelry with nothing but metal clay, or you can combine it with wire, sheet, beads, crystals, found objects, gems, and who knows what else, because the truth is we haven't even scratched the surface of metal clay's potential yet. Artisans have been working and experimenting with traditional craft media for thousands of years, while metal clay has been with us a mere a couple of decades.
By Merle White, Editor-in-Chief of Lapidary Journal Jewelry Artist
Source: Easy Metal Clay, Interweave, 2011.
Making Metal Clay Jewelry: Metal Clay Tools, Firing, and Finishing
A revolutionary material, metal clay is as if ceramic stoneware clay married metalsmithing. It has many advantages: it can be sculpted, rolled into sheets, extruded, and made into a paste. It also can be erected to a hollow form and used to construct intricate shapes. But perhaps its best attribute is that it is easy to master with satisfying, not to mention fast, results. It dries out quickly, so it must be covered to maintain its plasticity. It is packaged in airtight bags, which should only be opened when ready to use. To retain moisture between uses, store clay wrapped in plastic in an airtight container with a moist paper towel in the refrigerator until the next use. Make sure the paper towel and clay do not touch!
Shop Metal Clay Jewelry Products
Working with Metal Clay
Fresh metal clay is easiest to work with and is very moldable. This moist clay will be slightly cool to the touch (temperature is a good way of telling how fresh and moist your clay is). Use fresh metal clay for making sheets (roll a piece between two strips of matte board or craft sticks for consistent thickness throughout the sheets), pressing into stamps, rolling into logs, rolling into balls, sculpting, texturing, cutting with cutters, or poking holes in with straws. To maintain working time, the metal clay must be periodically hydrated. Do not overwet metal clay or it will break down and turn into a slurry (metal clay slip).
Bone-dry metal clay is completely devoid of all moisture and therefore maintains its shape. Bone-dry clay will be at room temperature. Use this for building forms, such as a box. You can sand it with various grits of sandpaper, carve it with a knife or engraving tools, burnish it, or wet it with a brush to make a slurry (metal clay slip) and attach other dry pieces. It is much easier to attach two dry components rather than trying to apply a wet bail to a pendant. It is also much easier to make repairs and apply finishing techniques in this stage, rather than after firing when the metal clay has sintered. Use the warming plate to speed drying time and get the clay bone dry. Clean up the piece by sanding all of the edges or use a wet paintbrush to smooth around the perimeter of holes so they aren't jagged. The more finishing that is completed in this stage, the less work later.
If the metal clay hardens into an undesirable shape, don't throw it away! Grind it with a mortar and pestle or chop it into a powder and add it to the slip jar (wear a dust mask to prevent inhalation). It can also be ground with a small amount of water to create a thick paste, which should then sit out until it is malleable. Dried and rehydrated metal clay is never as easy to work with as fresh clay, due to the grainy texture, but it should never be thrown away.
Firing Metal Clay Jewelry Creations
Without proper attention to the firing process, brittle and subpar metal clay pieces will result. Start with a cold kiln (adding metal clay pieces to a preheated kiln can cause bubbling or odd surface defects). Ramping the kiln to temperature also allows any unknown moisture to evaporate.
No pieces should be touching--lay metal clay pieces in a single layer on a firebrick, vermiculite, or investment powder. These provide cushioning or support for more intricate shapes, and in the case of firebrick, will improve mobility of the fired pieces. For most metal clay firing, you'll use the firebrick. Vermiculite and investment should only be used when necessary, as they're difficult to clean up. The vermiculite in particular is tricky because if the metal clay pieces you are firing "super heat," it can cause a dimpled surface where it is touching. This is rare, but it sometimes happens, especially on older, nondigital kilns.
The firebricks are also good to keep metal clay pieces from direct contact with the interior of the kiln, which could have fluctuations in firing temperatures. Firebricks can also be used to keep metal clay pieces standing upright. This is particularly helpful when making fused fine silver chain.
Investment powder is normally used in casting. It provides a pillowy cushion for hollow forms to rest in. This prevents the metal from flattening on one side and keeps the shape of the metal clay piece. The same theory applies for vermiculite. It won't burn off in the kiln.
Fire the kiln outside, protected from the elements, or in a well-ventilated area so you don't inhale fumes. Once the kiln reaches temperature, fire completely for two hours. Many claim that you can fire small items made out of the "quick fire" clays for ten minutes with a torch, but this can result in brittle, half-sintered pieces. They can break, revealing the chalky interior. Fire for two hours for fully sintered metal. There is no reason not to--if you spent time making your piece, fire it properly so it lasts.
Sintering Metal Clay
Metal clay is metal (silver, gold, bronze, or copper) particles mixed in an organic binder, which burns away in a kiln, leaving only the sintered metal behind. Sintering is the process of creating solid objects by heating particles or powders until they adhere to one another. Therefore, to achieve ideal results, it is important to remember that metal clay pieces must be fired in a kiln to fully sinter the metal and that the metal must be work hardened (by tumbling with steel shot, by burnishing with a brass brush, or by hammering). This lessens the inherent porosity.
Finishing Metal Clay Jewelry
Metal clay can be tumbled, brushed with a brass brush, or polished with polishing pads on a Dremel, Foredoom, or other flexible-shaft rotary power tool. Tumbling is the easiest, and it also work hardens the metal so it isn't brittle. Any run-of-the-mill rock tumbler will work. Add a drop of dish soap to the water and 1 pound (455g) of reusable stainless steel shot. The water should just barely cover the steel shot. Thread the pieces loosely onto a wire (if there are many) and twist closed. This step reduces the time spent digging through the shot. Allow pieces to tumble for about an hour and check the surface (differences in shot, the quantity of items in the tumbler, the soap, etc., can affect tumbling times). The metal clay pieces should be slightly shiny, but not completely bright. Remove and apply patina (if desired) and then return to the tumbler. It can take anywhere from another hour to two or more, so check periodically until you achieve the desired finish. For a satin finish, briskly scrub tumbled or nontumbled pieces with a brass brush and soap. If using polishing heads on a Dremel, be careful not to apply too much pressure, which can mark up the surface.
Metal Clay Toolbox
- Plastic flexible cutting boards: Lay these over your work surface to provide a nonstick work area, protect your table, and allow easy mobility of metal clay pieces. They are also good to scrape down and funnel dry clay into a slip jar.
- Tissue blades: Long, slim blades are good for cutting sheets of metal clay.
- Olive oil: Cover your hands, cutting board, and stamps (sparingly) with olive oil to prevent the metal clay from sticking to them. Too much olive oil will break down the clay.
- Beeswax and shielding lotion: These prevent the metal clay from sticking to your hands. They also keep the clay from drying out and irritating your skin.
- Bowl with sponge: Metal clay must be moist; therefore, moisten tools with a sponge and water for best results.
- Spray bottle with water: Use to mist metal clay and keep it moist.
- Slip jar: Slip is metal clay and water mixed into a paste and is essential for attaching metal clay parts.
- Paintbrushes (size 2 or 4): Utilize these for blending or adding water to dry areas of metal clay and attaching metal clay pieces together.
- Straws in various sizes: Coffee stirrers cut down to 1" (2.5 cm) are perfect for making holes in metal clay.
- Variety of cutters: Small cookie/candy cutters are perfect for cutting shapes from sheets of metal clay.
- Heating plate or coffee warmer: This heat source will quickly dry metal clay prior to firing.
- Cork clay: Imported from Japan, this type of clay (made from a mixture of cork and cellulose) is necessary to create hollow forms. It will burn away when the metal clay is fired in a kiln.
- Playing cards or matte board: You can use these to measure the rolling thicknesses of metal clay.
- Roller: This tool is excellent for making sheets of metal clay.
- Nail files: Have these handy in various grits for sanding small areas of bone-dry metal clay pieces.
- Ring mandrel: You will need this tool for shaping ring shanks.
- Liver of sulfur: This is used to create a patina finish on fired metal clay pieces.
- Container for clay: Use a plastic cup, cloche, or small ceramic pot or bowl to cover metal clay and keep it fresh.
- Kiln: To properly fire metal clay, it will be necessary to have a kiln that can reach 1,650°F (899°C) and hold this temperature for two hours. (Some metal clays can be fired with a hand-held torch as well.)
- Brass brush or tumbler with steel shot pellets: These items are used to properly polish and work harden metal, such as fired metal clay pieces.
Source: Enchanted Adornments by Cynthia Thornton, Interweave, 2009.
"Building" Metal Clay Jewelry in Fine Silver
Sculptural Metal Clay is a poem to the possibilities of pure fine silver, which is too often overlooked by traditional metalsmiths. Fine silver is just pure silver, with nothing added or alloyed to it, and it comes in many forms. Fine silver metal clay can be textured, sculpted, hand built, or coaxed into almost any shape imaginable, and, if properly worked and fired, can be almost as dense and durable as cast metal. Pure fine silver wire or sheet can not only be joined in the flame, or fused, without using solder or flux, but can also be imbedded into metal clay work and bonded in the kiln. This allows you to bring the solid structure of pulled or rolled metal to support your sculptural metal clay pieces, forming ring shanks, posts, armatures and prong settings.
The use of pure silver, whether in clay, sheet metal, or wire form, not only eliminates the need for solder or chemicals at the bench, it offers freedom from the time-consuming (and dirty) process of cleaning and polishing back the blackening that comes from heating alloys like sterling silver. When using fine silver, I can work metal from beginning to end safely and cleanly. I can make, in just a few hours, complex and detailed finished pieces, any one of which can be used as a prototype for casting if I wish. No wax carving is necessary, and my casting models are permanent works, not burned away in the molding process.
If you've ever done any traditional metalsmithing, those two paragraphs might sound revolutionary. Most people who work metal haven't been taught that fine silver can be fused, instead of soldered, or have been told that it is too soft to make "real" jewelry with. It isn't. You just have to make things slightly more solid or thicker in gauge. Properly handled, sized, and work-hardened, fine silver can serve beautifully, even in high-stress positions like ring bands and chain.
Although many talented artisans are working with fine silver wire and metal clay, I find that two vitally important steps in understanding and working any metal are often left out of most books and classes on metal clay: annealing and forging. For example, few metal clay artisans are aware of the true reason that a full firing is so important: the benefit of a deep annealing soak. Even fewer are aware that they can melt their scrap, cast it into an ingot of pure silver, and then roll their own fine silver sheet or draw their own wire.
Metal Clay Basics
The more I work with fine silver metal clay, the more possibilities I see, and the more interesting it becomes. I began using it in 1997, when I wanted to make my own specialty clasps and connecting elements for my beadwork. After exploring it for a year or so, I began learning traditional metalsmithing techniques so that I'd have a better understanding of my options for making cleaner connections and stronger metal clay pieces.
Fine silver metal clay is a valuable addition to any jeweler's bench, and it's not only possible, but delightful, to make finished work of professional quality in pure fine silver. Alloys like sterling silver are lovely in context and offer technical benefits in strength and durability, but in my opinion, nothing compares to the depth and beauty of pure silver. The time spent mastering the somewhat different skill sets to work with it is well worth your while.
I work with metal clay very simply and cleanly, and nothing I do is particularly complex or difficult. I don't add anything to it, and I try to move quickly and deliberately to my forms, without overhandling. My techniques for forming the clay are all classic hand-building skills, and I work with the clay differently in each of the basic stages of dryness.
I encourage you to explore even the most basic tasks fully. You haven't really rolled a ball of clay, for example, until you've rolled an utterly smooth, totally compressed egg of clay with just a few motions. Ideally, your work will be so neatly made that you'll never be forced to sand or file a single piece of dry or fired metal clay unless you choose to do so. Doing potentially dangerous things with any material should be a choice, not a default. In general, the less you file and sand metal clay or metal, the healthier you and your work environment will be.
Metal Clay Mindfulness
To keep your clay in good condition, it's best to work on just one component at a time, devoting your full attention to it with no interruptions. The more attention you can give to your fresh clay, the less attention it will need when it becomes dry clay or fired metal. Proceeding more mindfully when your clay is fresh will actually save you time in the middle and end stages of the work, and will give you a healthier work environment by allowing you to skip the filing and sanding, if desired.
Source: Sculptural Metal Clay by Kate McKinnon, Interweave, 2010.
Metal Clay Jewelry Featured Product:
Design earrings, bracelets, pendants, and rings in the versatile medium that gives you the accessibility of clay and the durability, luster, and genuine artisan feel of metal. With this remarkable material the possibilities are endless.
This amazing metal clay resource walks you through everything you need to know about this new jewelry-making medium.
Plus! A product comparison chart shows you what’s on the market at a glance!