The Ultimate Guide to Setting Gemstones in Metal Clay
Gemstone Firing Tests
Several knowledgeable colleagues in this field have performed extensive firing tests of natural and manmade gemstones at typical metal clay firing schedules, both unset and embedded in metal clay. The results of these gemstone firing tests provide a very helpful guide to how risky it is to fire a particular type of stone in place.
Not every stone tested produced identical results in the different firing tests. The tests also vary in terms of whether the stones were tested loose or embedded in metal clay, the types of clay in which the stones were embedded and the firing schedules tested.
I recommend consulting several of the following charts before deciding whether or not a particular stone is a good risk for firing in place in the type of clay and at the firing schedule you plan to use:
This guide by Mardel Rein of Cool Tools shows which natural and synthetic gemstones can be fired successfully in metal clay, by what methods (kiln and/or butane torch), with or without activated carbon, and at what firing schedules. It's formatted as a PDF file for easy printing and you'll want to keep a copy in your work area for frequent reference. It also includes tests at the longer/hotter BRONZclay and COPPRclay firing schedules (which is a helpful reference when using any type of base metal or sterling silver clay), and is the gemstone testing chart I turn to most often. It reflects the combined gemstone firing test results of Mardel Rein and Kevin Whitmore of Rio Grande.
This excellent and helpful PDF from Art Clay World USA provides tips for selecting stones suitable for firing in metal clay and for testing stones.
Mary Ellin D'Agostino provides a list of natural gemstones that can be fired in place successfully as well as some that should be set after firing.
This article on gemstones by Deric Metzger, G.J.G. A.J.P. is from the Fall 2004, Volume 7, Number 3 back issue of Studio PMC Magazine. You'll find a more extensive look at the results of Metzger's gemstone firing tests in metal clay in his book, Natural Gemstones in Metal Clay. A Bench Resource Manual.
Buy Kiln-Safe Gemstones, CZs and Lab-Created Stones From Reputable Suppliers
There are no hard-and-fast rules about which gemstones will survive torch firing or kiln firing in metal clay without changing color or fracturing/breaking at certain typical firing schedules, but fortunately there are some tips for minimizing the risk and also some excellent guides as to which gemstones, natural and manmade (i.e., lab-grown gems or synthetic stones) are good candidates for firing in (or with) metal clay based on extensive firing tests of various gemstones in different types of metal clay at different firing schedules and in different firing conditions (open air vs. carbon fired).
Always ask your suppliers whether the CZ and/or lab-created stones they sell have been tested for firing in metal clay. Try to buy from suppliers who test their gemstones and stand behind them as being "kiln-safe." For example, the product descriptions for many of the stones on the Gem Resources web site (see my Recommended Suppliers of Gemstones and Settings for Metal Clay further down in this article for the link) include results from gemstone firing tests in metal clay performed by artist and teacher Judi Weers.
Whenever possible, test-fire an identical stone (from the same shipment from the same supplier) by itself or, preferably, embedded in a small piece of the same type and formula of metal clay of the piece in which you want to fire to see whether it fractures or changes color. (You may wish to cover a loose stone with a piece of fiber blanket to contain the fragments in case the stone shatters during the firing test.)
Setting Gemstones in Metal Clay Before vs. After Firing
Caveat: Fire ANY Gemstone at Your Own Risk!
Following these tips and guidelines, especially the excellent charts of stone firing tests below, will help you minimize the risk of fired-in-place gemstones changing color, fracturing or breaking after firing in metal clay. However, each stone is unique and there are no guarantees, especially for natural stones. Even a stone identical in appearance to one that you test fired successfully may not react identically to the tested stone, especially if the stones are natural gemstones. Also, even a stone that appears to survive a test firing successfully may be weakened and fracture later on. If you are dealing with an expensive or irreplaceable stone, it's best to create a setting for it in the metal clay piece and then set it after the piece has been fired.
Metal Clay Settings Are Affected by Clay Shrinkage, Firing Schedule and Firing Method
Different metal clay formulas shrink at different rates and it's important to take the shrinkage of the metal clay into account when embedding gemstones to fire in place. Make settings large enough to accommodate shrinkage without putting undue pressure on the stone, but not so large that the sintered clay will not lock the stones in place in the metal securely.
When using higher-shrinkage metal clay formulas, make the stone settings a little deeper and wider than you would in low-shrinkage clay. If your design will allow it, also drill or cut out a small hole at the bottom of each setting for a point-back gemstone. This will help prevent the girdle of the stone from being pushed up above the clay as it shrinks, which would mean that the stone was not shrink-locked securely into the metal.
Only Set Stones Before Firing If They Can Withstand the Firing Schedule and Firing Method for the Clay Formula You Are Using!
Check the depth of the stone vs. the clay thickness. You'll need to add enough clay in the setting area (or embed the stone deep enough in thicker clay pieces) to cover the stone's girdle after the clay has been fired and has shrunk during the sintering process. This will shrink lock the gemstone into the metal. For a cabochon, the bezel needs to be tall enough to shrink around the lower curve of the stone and hold it in place after firing.
Carbon Firing vs. Open Air (AKA Atmospheric) Firing
Some gemstones that would fracture or change color in an open-air firing can survive being kiln fired in activated carbon. I strongly recommend consulting the gemstone firing test links above before deciding which stones to try kiln firing this way, and also test firing a sample stone in a small piece of metal clay before using it in a piece you care about.
Start with a brief, gentle binder burnout by placing the piece on a flame-proof surface and using a butane torch to ignite the binder in the clay, keeping the flame away from the gemstone(s). Wait until the flame burns out. Try to ignite the binder again. If it won't ignite, there is no remaining binder to burn out. Transfer the partially fired pieces gently onto a 1/2" deep bed of activated carbon in a kiln safe firing container, top with more carbon to a depth of 1/2" above the top of the piece, being extremely gentle when moving the pieces since they will be fragile after the binder burnout, and then kiln fire them in the activated carbon according to the clay manufacturer's directions.
How Do You Prefer to Set Stones in Metal Clay?
What's your favorite method for setting gemstones, glass or other objects in metal clay?
Setting Cabochon Gemstones Directly in Metal Clay to be Fired in Place
Make sure that the curved edges of the cabochon stone are embedded in the clay 1–2 mm below the surface of low shrinkage metal clay or 3 mm below the surface of higher shrinkage clay formulas so that after firing the clay will shrink-lock the the cabochon inside the metal.
Setting Faceted Gemstones Directly in Metal Clay to be Fired in Place
Faceted gemstones must be set so that the table (flat top portion) of the stone is recessed between 1 mm and 3 mm below the surface of the clay, depending on the shrinkage of the formula. This ensures that when the clay shrinks during firing, the girdle (narrow, faceted circumference) of the stone is locked into place so the stone cannot fall out or come loose.
Whenever possible, it is desirable to cut an opening directly under the culet or pointed bottom of the stone. This has two benefits:
- It minimizes the tendency of the clay to force the embedded gemstone upward as it shrinks during firing.
- It provides access to that the back as well as the front of the stone when cleaning the finished piece of jewelry.
How Deep is Too Deep?
As important as it is to ensure that the girdle of the stone is embedded deep enough in the clay to be shrink locked into place, embedding the stone too deeply will result in covering up too much of the crown of the stone and making the stone appear smaller than it is.
The ideal depth varies from one clay formula to another, depending on its shrinkage rate. Finding the optimal balance to achieve a secure shrink-lock setting and keep the maximum amount of the stone's crown exposed is something that comes with practice.
A Helpful Tip for Embedding Faceted Gemstones in Fresh Metal Clay
When embedding a faceted stone in fresh metal clay, getting the table of the stone perfectly level and the girdle recessed to the correct depth can be a challenge. The easiest way is to moisten the hole in the fresh bezel or backplate, wait a few moments and lightly oil the moistened surface. Stack spacer slats on either side and flush with the surface of the clay. Center the stone in the hole, then use an acrylic snake roller to press straight down against the spacer stacks.
Setting Tall Faceted Stones in Metal Clay
Setting a faceted gemstone with a tall pavilion can be a challenge, especially if the base in which will be set is significantly shorter than the stone. You can create an individual bezel set component using one of the methods I've described above and then attach it to your piece, but it may protrude above the surface more than your design calls for.
In that situation, there are a couple of solutions. One is to add layers of clay to the base or backplate just in the area where the stone will be set, creating enough depth to capture the girdle of the tall stone. The other is to make a shorter, partial bezel setting that captures the girdle of the gem but leaves the pointed culet exposed, and then add that partial setting to the base or backplace so that the exposed culet is embedded in it.
Option 1: Increase the Height of the Clay Where the Stone Will Be Set
One way to do this is to stack one or more cutouts on top of the backplate before setting the stone. Cut out your piece, then cut out a clay shape at least 2-3 mm wider than the gemstone and attach it to the piece where you want to add the gem. Then embed the stone into the fresh clay.
If the back of your piece is textured (or if both sides are), you will need to use a slightly different approach to avoid marring the texture on the back:
- Create the textured backplate and allow it to dry.
Note:Depending on the height of the stone and the desired thickness of the finished piece, you may want to drill a small hole partway through the non-textured side of the backplate (or the side that faces front, if both sides are textured), taking care not to drill through more than half the thickness of the backplate (or even less, if the backplate is very shallow).
- Create one or two fresh clay cutouts to layer on the front. This layer (or stack) needs to be at least as tall as the stone (or possibly slightly shorter if you drilled a hole partway into the backplate).
- If you are using two cutout layers, brush the top of one with water and then stack the other on top. Then brush the surface of the top layer lightly with water and cut out a hole in the center slightly smaller than the stone.
- Moisten the area on the back of the dried backplate (i.e., the front of the piece), wait a few seconds for the binder to reactivate, and then brush on a little more water and attach the fresh cutout(s).
- Embed the stone in the fresh clay, making sure the girdle is 1 to 2 mm below the surface of the stone and the table is level with top of the cutout(s).
Option 2: Create a Partially Bezel-Set Component
Another way to set a tall stone is to partially bezel-set it so that the culet and lower part of the pavilion are exposed, allow it to dry, and then create your piece in fresh clay and attach the pre-made component.
A variation is the method I used to create the silver charm below (shown in both front and back views), which has a tall, partially bezel-set, citrine-colored CZ on the front and a textured back.
- Create a shallow, partial bezel setting for the stone (which must be able to be fired in place), using the polymer clay tool described below. Leave the setting on the tool and set it aside to dry.
- Cut out a shape at least a little wider than the bezel, using a small cutter, scalpel or sharp craft knife. Cut a hole through the center wide enough to accommodate the exposed part of the pavilion. Allow it to dry.
- Create a textured backplate and allow it to dry.
- Refine all the components with salon boards, files, sandpaper, sanding sponges or the smoothing abrasives of your choice.
- Attach the shape cutout to the backplate securely, using your preferred attachment method (paste and pressure, or water and pressure with a slight back-and-forth wiggling motion until the moistened greenware "grabs" and sticks securely).
- Then attach the partially bezel-set gem to the center cutout component the same way.
How to Make a Bezel Making Tool From Scrap Polymer Clay
For either of the last two methods for setting a tall gemstone, you need to partially bezel-set the gem in a way that leaves the culet and the lower part of the paviliion exposed. In a pinch, you can embed the gemstone in a clay cutout, allow it to dry, and use a scalpel or sharp craft knife to carve away the setting from the culet and the lower part of the pavilion. But it's much easier (and less likely to damage your stone) if you create and use a polymer clay bezel tool.
In her excellent instructional DVD set "Contemporary Metal Clay 1" renowned jewelry artist, instructor and author Hattie Sanderson demonstrated how to make a nifty bezel-making tool out of polymer clay that is extremely helpful for making these types of partial bezels.
The basic idea is to create a thick, perfectly flat patty of conditioned polymer clay of even thickness throughout (you also can use a large circle cutter with a thick slab of rolled-out clay and smooth the edges with your finger), cut out a hole from the center with a clay cutter (or straw) that is slightly smaller than the girdle of the faceted stone you want to set, cure this polymer clay "doughnut" and sand it perfectly smooth and flat. You can seal it with a very thin, very even coat of polymer clay-compatible glaze or clear varnish, if you wish. I prefer to cut a piece of nonstick sheet to the size of the tool, cut or punch a matching hole in the center of the nonstick sheet, and place it on top of the cured and sanded polymer.
How to Partially Bezel Set a Faceted Stone Using This Tool
- Flatten a ball of metal clay to the desired height by placing it between two stacks of playing cards or thickness spacers or stacks of playing cards.
- From the center of this flattened patty, cut a hole slightly smaller than the girdle of the stone. Use a drinking straw, cocktail straw or very small clay cutters for this, depending on the size and shape of the stone.. (Cutting freehand with a clay pick, craft knife or scalpel won't create the perfectly straight hole with clean edges that you want for setting stones.)
- Oil the nonstick sheet (with the center hole you punched) very, very lightly and place it on top of the polymer disc, aligning the holes. If you sealed the bezel making tool, you can lightly film the surface of it with a drop of olive oil if you don't want to use a nonstick sheet.
- Position the clay on top, aligning the hole with the holes in the nonstick sheet and the polymer disc.
- Moisten the inside and top edges of the hole in the metal clay with a drop of water; wait a few seconds for the moisture to be absorbed.
- Use serrated tweezers to carefully enter the stone over the hole. Then slowly and carefully press the stone straight down until its girdle is 1 to 2 mm lower than the surface of the clay and its table is perfectly level or flush with the surface.
- Moisten the surface of the clay again, avoiding the stone, and let it absorb for a few seconds. Then use a small clay cutter, scalpel or sharp craft knife to trim the clay evenly around the gem, creating the bezel shape.
- Allow the bezel to dry, then carefully remove it from the nonstick sheet (or oiled polymer disc) and file or sand the edges smooth.
- Before firing your piece, clean the stone carefully (even if it looks clean) with a sponge-tipped swab dipped moistened with rubbing alcohol.
- If the clay is deep enough, use a small straw or other cutter to cut out a hole slightly smaller than the stone.
- Moisten the surface of the clay around the hole very lightly and wait a few seconds for the moisture to be absorbed.
- Center the stone over the hole and press it straight down into the clay until the girdle (for faceted stones) or the outer curve (for cabochons) of the stone is about 1 mm below the surface of the clay, or 2–3 mm below the surface for higher shrinkage clay formulas.
Metal Clay Ball Bezel Setting I
- Cut a hole in the clay slightly smaller than the stone's diameter.
- Roll a small ball of lump clay and flatten it slightly into a disc a bit wider than the stone.
- Place the disc over the hole and, using tweezers, place the stone into the center of the disc.
- Press the stone into the disc until the girdle is covered and the table is level.
Metal Clay Ball Bezel Setting II
- Moisten the area on your design where you want to add a bezel-set stone.
- Roll a ball of clay about twice the size of the stone and press it onto the moistened area of your design.
- Lightly moisten the ball and allow the water to absorb briefly.
- Use a pencil, pointed clay shaper or similar conical tool to make a cone-shaped hole for the stone.
- Press the stone straight down into the hole so the girdle or outer curve of the stone is about 1 mm below the surface or 2–3 mm below the surface for higher shrinkage clay formulas.
Bezel Setting Gemstones as Individual Metal Clay Design Components
Setting individual gemstones in metal clay bezels to use as components is one of my favorite ways to bezel-set safe-to-fire gemstones in fresh metal clay. Setting the stones separately tends to minimize distortion and allows the setting to be refined as much as desired prior to attaching the pre-set stone to a metal clay jewelry design.
Many jewelry artists like to use small amounts of leftover metal clay to bezel set gemstones and keep a variety of them on hand to use as design components.
How to Bezel Set Individual Gemstone Design Components
Make sure the gemstone you want to set is safe to fire in place.
- Roll out a slab of metal clay at least 1 mm thicker than the stone.
- Use an oiled straw or small cutter slightly smaller than the stone you want to set to cut out a hole in the clay.
- Lightly moisten the surface of the clay around the hole, let the moisture absorb into the clay for a few seconds, and then center the stone over the hole.
- Use an acrylic snake roller or an empty CD or DVD case to press the stone straight down until the girdle of the faceted stone or outer curve of the cabochon is 1 mm beneath the surface of the clay (2–3 mm for higher shrinkage formulas).
- Apply a clay release agent to a small clay cutter, craft knife, scalpel, clay blade or tissue blade and cut around the stone, leaving a margin slightly wider than you want the bezel to be. Remove the excess clay and allow the rough bezel to dry.
- Carve, file, and/or sand the bezel to refine it.
If you make these bezel set gemstone components in advance, store them in closed containers marked with the metal clay brand and formula you used to make the settings. Having a selection of unfired bezel-set stones to choose from makes designing and creating new metal clay jewelry pieces faster and more efficient.
How to Add a Bezel-Set Gemstone Component to a Fresh Metal Clay Design
- Moisten the area where the setting will be attached and cut a small hole (to allow access to the back of the stone for cleaning).
- Moisten the back of the bezel setting and press it onto the moistened fresh clay, centering it over the hole.
How to Add a Bezel-Set Gemstone Component to a Dried Metal Clay Design
- Drill a hole through the dry metal clay piece to allow access to the back of the stone for cleaning.
- Moisten the surface of the clay around the hole and on the back of the bezel.
- Center the bezel-set stone over the drilled hole and press it down firmly, wiggling it slightly until the clay grabs and the bezel won't move. Alternatively, use metal clay paste to attach the bezel-set stone over the hole.
Metal Clay Syringe Settings: Syringe Bezels and Prong Settings
Using metal clay syringe is a popular and widely used approach to setting stones directly in the clay.
- Cut a hole in the clay slightly smaller than the stone to be set.
- Extrude a line of syringe clay to create a rim surrounding the edge of the hole.
- If necessary, add a second or third line of syringe clay to make the bezel tall enough to cover the girdle of the stone.
- Using tweezers, place the stone in the setting and gently press the girdle into the syringe clay until the stone's table (top) is level and the girdle is covered by the syringe clay.
- Optional: Add syringe decorations around the top of the bezel, and draping over the stone, if desired, for added security.
- Set the stone in a flush setting.
- Moisten the clay around the stone and extrude syringe prongs that extend over the stone, making them a bit longer than you want them to be after firing to allow for shrinkage.
Note: If you make the syringe clay prongs too short, after the clay shrinks during firing they won't be long enough to curve over the edges of the stone and hold it securely.
Additional Methods for Setting Gemstones In Fresh Metal Clay
Here are some other popular techniques to set your stones in fresh, moist metal clay.
- Roll a coil of lump clay and brush it lightly with water.
- Let the water soak in for a few seconds, then form the coil into a loop just slightly smaller than the stone you want to set.
- Use a tweezer to center the stone in the loop and press it into the clay so the girdle is covered and the table is level.
Note: This is also known as a rope or snake setting.
Alternate Coil Setting Method
- Moisten the area of the moist clay design where you want to set the stone.
- Press the stone into the clay so the girdle is flush with the surface.
- Add a line of syringe to the clay directly around the stone to cover the girdle.
Layered Cutout Setting
- Lightly moisten the area on your fresh clay design where you want to set the stone.
- Roll out a small amount of additional clay. Leave it smooth or texture just the top surface, if desired.
- Use a knife, straw, aspic cutter, etc., to cut out a small shape.
- Press the shape onto the moistened area of your design, then dip the a small paint brush in water and run just the tip of the wet brush along the edges of the seam.
- Use an drinking straw or cocktail straw of the appropriate size to remove a plug of clay slightly smaller than your stone from the center, cutting through both layers.
- Press the stone into the setting, making sure the girdle of the faceted stone or outer curve of the cabochon is embedded below the surface.
Faux Pavé Setting
To simulate a pavé setting effect:
- Embed tiny faceted stones into a narrow coil or snake of clay, making sure that the stones are very close but not actually touching. Each stone must be surrounded by a very small amount of metal clay on all sides, which will shrink-lock them in place when the clay is fired.
- Roll out the clay for the main body of the piece and cut a slit slightly longer than the faux pavé strip you just made, slicing all the way through the clay.
- Brush some slip or paste over the sides of the stone-studded strip, taking care not to get any slip on the stones.
- Lay the clay slab on top of the strip while carefully opening the slit just enough for the row of stones to show through.
- Gently press the sides of the slit against the side of the faux pavé strip and smooth the seams with a damp brush and some paste or slip, again being careful not to get any on the stones.
- Allow to dry.
- Turn the piece over and apply a generous layer of paste or slip to the back of the seams.
Special thanks to renowned jewelry artist Angela B. Crispin for sharing this technique with me.
Do You Prefer to Set Fireable Gems Before or After Firing Your Metal Clay Pieces?
Certain gemstones cannot be fired in place at all. Others cannot be fired in an atmospheric (open air) firing but can survive kiln firing in activated carbon successfully. Others can be fired in place in an atmospheric firing or in activated carbon, but even those don't need to be fired in place; they can be set after firing.
The choices as to how and when you set a particular gemstone involve not only the stone's limitations but also your design aesthetic and considerations related to the shrinkage of metal clay around fixed-sized objects, whether bezels, prong settings, or the stones themselves and the possible distortion or cracking that can occur.
Setting Glass in Metal Clay Jewelry
Glass can be set in fine silver metal clay either before or after firing (or in any type of metal clay after firing if an appropriately sized setting has be embedded in the piece before firing). Whether you set the glass before or after firing depends on the effect you want to achieve.
Embedding sea glass in your piece and firing it in place is not recommended. The sea glass will likely lose its frosted surface and it may slump or change color at the optimal firing schedules for most metal clay formulas. However, you can embed wire prongs into your piece and set the sea glass after the piece has been fired.
Setting Glass Loosely Before Firing
Surround a glass cabochon or other embellishment loosely with clay if you want the glass to slump, dome or flatten during firing.
- Create a recessed area for the glass in fine silver metal clay, making it a bit larger all the way around than the glass to allow for the clay's shrinkage. You want to shrink-lock the glass in place, but not so much that it puts pressure on the glass and causes it to develop stress fractures. Some artists press the glass partway into the clay and then wiggle it from side to side and front to back to create a slightly enlarged recess of the correct shape and then remove the glass.
- Allow the clay to dry without the glass.
- It is a good idea to carve a slight undercut around the bottom inner edges of the recessed area. These creates a small channel for the bottom edges of the softened or molten glass to ooze into, helping to lock the glass in place after firing and cooling.
- Carefully brush out any clay dust with a soft paint brush.
- Clean the glass carefully with isopropyl alcohol, AKA rubbing alcohol, before replacing it in the center of the recessed area.
- Optional: Add some decorative strands of syringe clay across the top of the glass to help secure the glass in place after firing. (Consider it insurance.)
Creating an Empty Metal Clay Setting
Use this method to retain the original size, shape and surface texture of the glass or if you are using a clay formula other than low-fire fine silver. Then set the glass after firing the metal.
- Create a setting in the unfired metal clay piece using commercial or metal clay bezel wire, metal clay snakes or metal clay syringe or by making a recessed area where the glass can be glued after firing.
- If you are creating an unfired metal clay bezel or making a recessed area for the glass in the unfired clay, be sure to factor in the shrinkage of the clay formula to calculate the enlarged size to make the metal clay bezel or recessed setting area so it will be the correct size and shape to fit the glass after firing the clay.
Regarding firing schedules, the exact temperature and time depends on the type of metal clay, the type of glass and how much slumping you are willing to accept.
Firing Schedule for Fine Silver Clay with Glass
In order to avoid devitrification or creating stress in the glass, you need to use a cool firing schedule and cool the glass slowly. One firing schedule that works well is to fire to 1250°F / 677 °C and hold for 30 to 45 minutes. Turn off the kiln and let the piece cool inside the closed kiln overnight.
Project: Set a Dichroic Glass Cabochon in a Low-Fire Silver Clay Pendant
Setting Gemstones in Dry Metal Clay AKA Greenware
The biggest advantage to setting gemstones in metal clay after it has dried but before it has been fired is that you get the best features of setting gemstones in wet clay (i.e., you can shrink-lock the stones in place as the clay sinters) and setting gemstones after the clay has been fired (i.e., you don't risk distorting the clay or marring the surface). Here are several useful techniques for setting gemstones in dry metal clay.
Make sure the clay is thick enough so the girdle of the stone will be covered after pre-finishing. When the clay is bone dry, pre-finish it (sanding, etc.). Use a very small drill bit in a hand drill/pin vise to drill a pilot hole all the way through the clay. Replace the drill bit with a jeweler's stone-setting bur approximately 10% larger than the stone you will be setting, or use a drill bit that's the same size as the stone but drill a little deeper than usual. Test-fit the stone in the hole to make sure that the girdle is slightly below the surface of the clay. If necessary, remove the stone and enlarge the hole slightly. Carefully brush off any loose dust from the clay and from the gemstone. Clean the stone thoroughly, then place it back in the hole. Make sure it's level and clean the top of the stone with alcohol and a sponge-tipped cosmetic applicator or cotton swab. Note: If the stone is set on a curve, use white glue to hold it in place on the way to the kiln.
Optional step (but I find it really helps to make sure the stone is shrink-locked securely after firing): Using an applicator tip with a tiny hole, extrude a very fine line of syringe just inside the edge of the drilled setting hole. Alternatively, brush a little paste clay inside the setting hole. Place the stone into the hole as described above, then wipe the edge of the setting with a damp brush to make sure no syringe or paste clay squeezed out above the stone. Let the paste or syringe clay dry completely. If any clay ends up on top of the stone, scrape/flake it off the stone gently once it has dried. Clean the top of the stone with alcohol and place in the kiln.
Tip: You may want to create a photopolymer plate to impress starter holes in the clay where the stones will be set.
Note: If you are unfamiliar with gypsy settings, I recommend reading this excellent article by noted jewelry artist and author Charles Lewton-Brain on the traditional Basic Gypsy (flush mount) Setting technique for setting faceted gemstones flush in metal jewelry.
Special thanks to Mary Ellin D'Agostino, Tonya Davidson, Maggie Bergman and Priscilla Vassão for their advice on this technique.
Bezel Settings For Cabochons That Will Be Set After Firing
The most popular way to set cabochon stones that are not safe to fire in metal clay is to create custom bezel settings with traditional or metal clay bezel wire.
Fine Silver Bezel Wire Settings
- Place a cabochon on a flat surface and wrap a strip of fine silver bezel wire around the base of the stone.
- Test fit the bezel by lifting it above the stone and then lowering it onto the stone again and adjust the fit as necessary. The stone should slide in and out of the bezel easily, but there should be no gaps between the stone and the bezel. When you have a good fit, mark the spot where the wire overlaps.
- Cut the bezel strip flush, erring on the side of cutting it slightly too long rather than slightly too short. File the ends flush, filing down the metal a bit if necessary, to create a tight seam when the ends are butted together.
- Use one of the following methods to complete your bezel.
Method 1: Embed the bezel into the clay and seal the joint neatly with paste clay or homemade PMC3 oil paste. Keep most of the paste on the outside of the joint so you don't change the fit of the bezel. Let the clay dry, fill any gaps, dry and fire. If necessary, you can file and sand off any excess paste carefully after the bezel has been fired.
Method 2: Seal the joint of the bezel with paste clay or, better yet, with metal clay oil paste or commercial Art Clay Paste. When dry, fire the bezel separately, file the seam smooth and embed in fresh clay as above. This is the method I used to bezel set the dichroic cabochon in a domed, textured metal clay pendant component the photo above.
Tabbed Fine Silver Bezel Wire Settings
Metal Clay Findings sells fine silver bezel wire with tabs that extend along one edge of the wire and is designed specifically to be embedded in metal clay. The company also makes ready-to-use tabbed bezels to fit 3 mm, 4 mm, 5 mm, 6 mm, 7 mm and 8 mm round stones and 6 x 4 mm and 8 x 6 mm oval stones. The tabbed bezel wire created a very secure bezel setting because the bent tabs are embedded in the clay, which shrink locks them in place during firing. Metal Clay Findings provides detailed information for using its tabbed bezel wire.
Tips for Embedding Commercial Bezel Wire into Metal Clay
- Bezel wire should be wide enough to hold the stone in place securely after burnishing plus another 1 mm in width (i.e., height) that will be embedded in the metal clay. If in doubt, choose wider wire and file or sand down the bezel to the correct height after firing.
- Scuff, scribe or coarsely sand to roughen the 1 mm edge of the wire that will be embedded.
- Draw a line on the bezel wire scant 1 mm away from the lower edge with a fine-tipped marker to help you embed the bezel in the clay to an even depth all the way around.
- Sand the surface of the metal clay inside the bezel flat and level before firing, if necessary, e.g., if the clay where the bezel wire is being embedded is curved and/or textured, to create a level seat for the stone when it is set. (See the example of a flat seat I created in a curved and textured bezel setting in the photo.)
Tip: To avoid distortion caused by shrinkage, you can create a flat area on the clay where the bezel will be attached and fire it. Be sure to calculate the size of the area accurately so that it shrinks to the correct size for the bezel during firing. Then use metal clay oil paste or solder to attach the bezel to the prepared area.
Learn From Expert Lisa Barth
My friend and colleague Lisa Lynn Barth is an internationally known jewelry artist and highly sought-after metal clay teacher who is known for using tabbed bezel wire settings in her distinctive cabochon gemstone jewelry.
I've written an in-depth book review of Lisa Barth's book, Designing From the Stone that includes fabulous and inspiring photos from the book that Lisa was kind enough to provide to me digitally along with her permission to use them in my online review.
Metal Clay Bezels for Cabochons from Art Clay Silver Paper Type or PMC Sheet
Beautiful custom bezels can be created with metal clay paper (sheet) to accommodate cabochons of any size and shape. This technique was pioneered by talented metal clay artist Jennifer Kahn and often is referred to as the "Kahn bezel" for that reason. Jen's excellent chapter in the superb book explains in detail how to size the metal clay bezel setting so that it shrinks to the correct size after firing and also offers some metal clay bezel variations. PMC Technic: A Collection of Techniques for Precious Metal Clay
Textured Metal Clay Bezel Wire Strips for Setting Cabochons
You can use shallow textures (including tear-away textures) to create textured bezel wire strips for setting cabochons. If you create your own metal clay textures, you can use them to create unique textured bezels that can add more of your artistic voice and also more value to your bezel set metal clay pieces. You can choose (or create) a texture to complement or contrast with the patterning in the gemstone cabochon. And a textured bezel can help draw more attention to the cabochon it frames.
Jennifer Kahn Rich's PMC Flex Silver Textured Bezels
Jennifer has continued to develop and refine her "Kahn bezel" technique over the years. She discovered that using PMC Flex silver clay allowed her to make textured fine silver bezels with the ease of texturing of lump clay and the flexibility of metal clay paper.
She wrote a detailed blog post about making textured silver clay bezels with PMC Flex that includes a video demonstration.
How to Make Textured Bezel Wire from Any Metal Clay Type, Brand or Formula
This method enables you to create textured bezels using any type of metal clay — fine silver, sterling silver, bronze, copper, steel, etc. — and any brand or formula of metal clay.
- Roll out a sheet of metal clay 1-2 cards thick (depending on the depth of your texture, the shrinkage of the clay, and how thick you want your bezel) on whatever surface you plan to cut it on. I like to use a jumbo rolling frame to maintain a perfectly even thickness throughout, or you can make your own rolling frame.
- Texture the clay without lifting it from the rolling surface. You want a small amount of surface tension between the clay and the cutting surface.
- Cut a long strip somewhat longer and slightly wider than you'll need for your bezel strip (an adjustable dual-blade craft knife makes it easy to get a uniform width along the entire strip), then peel off the excess clay without disturbing the textured strip. The reason for not lifting the clay is to avoid getting any air between the bottom of the clay and the nonstick sheet.
- Allow the textured side of the clay to air dry for 30-60 seconds, just long enough to allow it to firm up so that you can lift and manipulate it without marring the texture (but not so much that it cracks when you curve it into the bezel shape), while keeping the non-textured side moist (because it is sealed against the nonstick sheet).
- Then form the strip into a bezel, sized to allow for the clay's shrinkage, mitering the edges and sealing the joint well with paste. After it dries, lightly moisten the joint and reinforce it with fresh clay.
How to Make a Nearly Invisible Seam on a Textured Metal Clay Bezel or Ring
Artist, author, teacher and metal clay pioneer Celie Fago taught me a brilliant trick for making the seam on a textured bezel or ring nearly invisible.
- Cut the textured metal clay bezel strip a few millimeters longer than you need, then shape the bezel strip and join the ends.
- After the clay and especially the joint have dried completely, take a sharp, stabilized blade and cut cut straight down through the bezel on either side of the joint, angling the ends of the blade so both ends are beveled at the same angle.
- Moisten the inside of the bezel lightly, cover it with plastic wrap and allow the moisture to absorb into the clay.
- Remove the plastic and join the beveled ends with thick slip, taking care not to let much paste ooze out on the textured side of the joint.
- Allow the joint to dry completely, flick off any excess slip on the textured side with the tip of a sharp blade or the tip of a fingernail and reinforce the back of the joint.
- When the joint is dry, refine the inside of the bezel and use micro carving tools, files, clay, etc. as needed to make the patterns of the texture on either side of the seam appear to flow without interruption.
Wanaree Tanner Demonstrates Making Solid Metal Clay Bezel Wire
Making Pierced Metal Clay Bezel Wire (AKA Gallery Wire)
Wanaree Tanner also created another video tutorial for Metal Clay Artist Magazine that shows how to use the to cut out simple or intricate patterns in metal clay sheet or metal clay paper and cut it into strips for bezel wire. In it, she walks us step-by-step through how to use the Silhouette Studio software to tell the cutter which cuts to make. Fascinating and extremely helpful, the Silhouette CAMEO cutting techniques that Wanaree demonstrates will open up a whole new world of design possibilities for your metal clay bezel designs. Silhouette Cameo electronic die-cutting machine
I highly recommend getting the light hold cutting mat if you're going to be cutting metal clay paper or sheet. The adhesive on the regular cutting mat is much too sticky and you'll tear apart your delicate metal clay sheet and cutouts when you try to remove them from the regular mat. An alternative is to smooth a clean white T-shirt lightly against the surface of the regular Silhouette cutting mat and then pull it off to make it less sticky.
Creating Custom Bronze Clay Framed Bezel Settings for Cabochon Stones to Be Set After Firing
Using dried Creative Paperclay to make cabochon placeholders works fine for making custom bezels from fine silver clay, but the placeholders cause problems when they're fired with base metal clay.
Robin Ragsdale developed a terrific solution to the problem by pre-firing an enlarged Creative Paperclay placeholder or "dummy stone" and then filing it down to match the contours of the bottom of the cabochon before placing it in the bronze clay bezel and carbon firing the setting.
She wrote up her method in a great step-by-step bronze clay framed bezel tutorial published on Creative Fire.
Using Silver Bezel Cups to Set Calibrated Cabochon Stones
An easy way to set calibrated cabochon gemstones is to embed metal bezel cups into the clay. If you are using fine silver clay you can embed either fine silver bezel cups or sterling silver bezel cups that have been depletion gilded (heated and pickled repeatedly to bring the oxides to the surface and remove them, leaving a layer of fine silver on the surface). For depletion gilding sterling silver findings, you can use either a traditional jeweler's pickle (such as Sparex #2) or a citric acid pickle, which is safer to use. If you are using a carbon-fired silver clay formula, such as PMC Sterling or enriched 960 sterling clay, depletion gilding of sterling findings is not required.
Embedding Calibrated Bezel Cups in Metal Clay
The bezel cups must be embedded securely into the clay in a way that allows the clay to physically or mechanically lock them into place as the clay shrinks. Here are two methods I recommend.
- Scuff the bottom of the bezel cup with coarse sandpaper to give the metal some "tooth" for the paste to grab onto. I recommend sanding in one direction and then at right angles to make a cross-hatch pattern.
- Drill one or two small holes in the bottom of the bezel cup before embedding it in the clay or attaching it with thick silver clay paste, preferably homemade PMC oil paste or Art Clay Silver paste, both of which can be fired up to 1650 °F / 900 °C.
- A little of the clay or paste should push up through the hole(s); tamp it down slightly so that it overlaps the edges of the hole(s) and is fairly level with the interior bottom of the cup. This will create a rivet-like mechanical connection between the cup and the metal clay underneath.
- Sand the bottom of the bezel cup with rough sandpaper (see Method 1). Also sand a very narrow strip around the base of the outer wall of the cup. This area will be covered by a syringe or clay border in step 4.
- Apply paste, preferably homemade PMC oil paste or Art Clay Silver paste, to both the bottom and the lower outer edges of the cup.
- Embed the bezel in the clay. Use the tip of a wet brush to moisten a narrow strip of the clay surrounding the base of the cup, taking care not to disturb the paste you applied to the bottom of the outer wall.
- Surround the base of the bezel with a border of syringe or a thin coil or twisted rope of clay and attach it to the base of the cup and the moistened clay surrounding the bezel.
Optional: To make an even more secure connection using Method 2, drill a few small holes around the outer base of the cup so that as the syringe or clay coil or rope shrinks, it will push into the holes to create a mechanical connection. This is how I embedded the 3 mm fine silver bezel cups in the marquise-shaped fine silver earrings shown above, since the tiny natural blue topaz cabochons could not be fired in place safely.
Prong Settings for Faceted Gemstones That Will Be Set After Firing
Commercial prong settings provide a professional appearance as well as speed and ease of use when setting calibrated faceted gemstones in metal clay.
You also can embed wire in metal clay prior to firing to create custom prong settings for faceted gemstones.
Commercial Silver Prong Settings for Faceted Gemstones With Pointed Backs (Culets)
Commercial prong settings are embedded in clay similarly to the method for embedding bezel cups. Jackie Truty wrote a helpful PDF article on Attaching and Setting Stones into Pure Silver Settings that provides excellent step-by-step instructions for how to embed a fine silver prong setting into fine silver metal clay and then set a faceted gemstone in it after firing. Jackie included lots of helpful tips to ensure a successful result. You can find it on the Art Clay World website. Highly recommended.
Custom Wire Prong Settings for Faceted Gemstones
You also can make your own custom prong settings by embedding wires into the metal clay and firing, then trimming the wires, rounding the ends with a cup bur and filing notches to seat the stone's girdle firmly.
Prong Settings For Cabochons or Irreguarly Shaped Objects That Will Be Set After Firing
You can set large or unusually-shaped cabs, rocks, or just about any object you wish by making custom wire prong settings.
How to Make a Custom Fine Silver Wire Prong Setting in Metal Clay
- Fold lengths of annealed fine silver wire in half (but don't crease the wire at the fold).
- Bend the ends of the wires at 90-degree angles to form "legs" to ensure that the ends of the wire will be securely shrink-locked into place during firing.
- Place your cabochon on the moist clay and embed the bent legs of each wire prong into the clay around the edges of the stone. The wire prongs won't shrink, but the clay into which they're embedded will, so leave a little space around the stone to allow for shrinkage.
- Remove the cabochon.
- Seal and strengthen the area where the wire enters the clay with paste and, if desired, syringe clay.
- After firing, place the stone inside the prong and gently bend the prongs over the cabochon, taking care not to twist the prongs.
Variation: Before firing, decorate the prongs with syringe clay, paper-type clay cutouts or other metal clay adornments secured with paste clay or syringe.
Settings for Pearls and Half-Drilled Beads
The easiest way to add pearls or half-drilled beads to your design is to securely embed a length of silver wire (either fine silver or depletion-gilded sterling silver) into the clay, leaving a piece exposed to serve as a post or peg. After firing, epoxy the pearl or bead onto the wire.
Alternatively, you can embed a fine silver (or depletion-gilded sterling silver) earring post into the clay and then add the pearl or bead with epoxy after firing.
Questions & Answers
I want to set a trillion shaped gemstone in a PMC piece after firing. Would you suggest using Creative Paperclay to replicate the stone? Would I still would need to make bezel slightly larger to allow for shrinkage?Helpful 1
When embedding a calibrated, fine silver-bezel cup into PMC 960-enriched sterling clay, should I leave room for shrinkage between the bezel cup and clay? Will the bezel cup hold its form, or will it distort when the clay shrinks? What about a handmade bezel wire fired in place?
I haven't ever tried embedding a calibrated FS bezel cup or a handmade FS bezel into 960 sterling clay, either hand-mixed or commercial formulas. However, since shrinkage is higher for 960 than for fine silver, your concern is valid. Even if the bezel cup didn't distort, as the backplate shrank it might pull away from the hole where you attached the bezel cup.
If it were my piece, I think I probably would make a flat area for the bezel cup or stone, fire the backplate, and then either attach the bezel or bezel cup with oil paste or overlay paste and refire or solder the bezel in place.
© 2006 Margaret Schindel