METAL CLAY AND MICRO-MOSAIC PENDANT
by Michela Verani
Micro-mosaic is an ancient art form of miniature glass mosaics that were popular during the Victorian era and reportedly no longer are made. Micro-mosaic pieces can be intricately patterned, with microscopically small glass components and carefully grouted, ground and polished surfaces, or simpler and more economical, such as Venetian micro-mosaics in which the pieces are larger and the surface is neither ground nor grouted. . This project uses the Venetian style of micro-mosaic and my own processes.
I use several types of glass rods: flat noodle-shaped rods called smalti filati, multicolored patterned and shaped rods similar to millefiori (tessera), millefiori, and some small lampworking rods. I buy my smalti filati or glass rods that make up the background colors from Miami Mosaics. They carry the filati in quite a number of colors and you can buy sampler mixes. (See the Resources section at the end of this article.) According to some sources, the patterned or complex tessera rods are not being made any longer, so my main source for tessera is damaged micro-mosaic pieces. Micro-mosaic jewelry often is available on eBay, and it’s worth checking out as a potential source not only of damaged pieces to take apart, but also of design inspiration. I also have developed relationships with some antique shops whose buyers will purchase damaged micro-mosaic jewelry for me when they find it and then contact me. You might want to try to develop your own similar source(s) of damaged micro-mosaic pieces. Also, just in case the information I’ve found about micro-mosaic work no longer being done is true, please don’t destroy undamaged micro-mosaics to re-use the glass pieces for your own designs! These are valuable examples of a potentially lost art form that should be preserved for future generations.
Experience Level – Advanced
Edited by Jeannette Froese LeBlanc, Joy Funnell and Margaret Schindel.
Project Materials and Supplies
Micro-mosaic glass – Smalti filati, patterned millefiori, lampworking rods, old micro-mosaic glass
25 g Metal Clay Silver (Artist used Art Clay®650 clay, low fire, slow dry formula, but PMC will work the same.)
Metal Clay Silver paste
Metal Clay Silver syringe
20-inch sterling silver finished rope chain
Tools & Supplies:
Glass nippers or cutters
Scotch® Double Stick Tape
Colored rolling slats or playing cards
Craft knife with a sharp blade (e.g., X-Acto® brand)
3M™ Softback Sanding Sponges in Fine, Super Fine and Micro Fine Grits.
Micro carving tools (e.g., Dockyard brand)
Comfort handle for clay syringe (optional)
Liver of sulfur
Pyrex® measuring cup
Cup or bowl of ice water
Silver polishing cloth (e.g., Sunshine® Polishing Cloth)
Weldbond® Mosaic Glue
Tumbler and stainless steel shot (Note: A vibratory tumber should not be used with stainless steel shot, use ceramic media instead which is available from Rio Grande.)
Cup warmer and Pyrex® cup
Design the pattern.Place slices of the glass rods onto a sheet of paper and move them around until you get a design that pleases you. Place strips of double stick tape on another piece of paper and transfer the micro-mosaic design onto the taped paper so that it will stay in place. (Tip: It’s much easier to place and move the pieces of glass around with tweezers than with your fingers.) Place pieces of smalti filati around the sides of the piece to make a solid border around the flower design in the center.
Measure the outer dimensions of the smalti filati border with calipers. Increase this measurement by 10% to account for shrinkage of the clay, and cut a paper template to this size. The template will be used to create the depression or well into which the glass micro-mosaic will be set.
Roll out the base. Roll out 15 g of clay to a thickness of 1mm [.04”] on a piece of non-stick sheet, using a lightly-oiled roller and either blue rolling slats or 2 stacks of 4 playing cards. Draw and cut a template for the base approximately 6 mm [1/4″] larger than the well template and place it on the clay. With a lightly-oiled craft knife, cut around the template to create the base. Dry the base piece in a dehydrator or allow it to air dry.
Make a bezel for the mosaic. Center the well template on the base and trace very lightly around it with pencil; this will be the guideline for attaching the bezel strip. Roll out 6 g of clay to a thickness of 2 mm [0.8″] using purple rolling slats or two stacks of 8 playing cards. Using a lightly-oiled tissue blade (or a straight edge and a craft knife), cut a strip 3 mm [1/8″] wide for the bezel. Moisten a paintbrush with water and lightly wet the border defined by the pencil line. Attach the bezel strip to the base with paste, using the pencil guideline to align the inner edge. Trim the ends of the bezel strip flush, moisten the ends and attach them together securely with paste or syringe. Allow to the piece to dry and then sand it smooth with progressively fine grits of sanding sponges.
Carve the bezel. To carve the bezel into a rope pattern, draw evenly spaced, diagonal lines on the clay with a pencil. Moisten the bezel clay lightly with a damp paintbrush to keep the clay from chipping as you carve it. Use micro carving tools to carve the rope pattern into the bezel. Sand the piece with successively fine grits of sanding sponges until it is smooth and pre-finished to your satisfaction.
Decorate the back. Since the back was a blank canvas, I decided to decorate it. (Alternatively, I could have textured the back of the base when I rolling out the clay.) My design echoes the micro-mosaic design on the front, but your design can be anything you like. Sketch the design onto the back of the piece with a pencil. Use approximately 2 g of clay to create your design components. To make flowers and leaves like the ones in my design, roll a snake or coil of fresh clay and then slice off short slices. Roll them into smooth, compact balls and flatten them a bit, and then shape them if desired (e.g., pinch one end of a flattened clay ball to make a tiny leaf shape) and use the side of a needle tool to press details (such as leaf veins) on the leaves and flower petals. Moisten the penciled design on the back of the piece with a damp paintbrush, and attach the leaves and flowers until you are happy with your design.
Make the bail. For the bail, roll out 1 g clay to a thickness of 0.75 mm [0.3″] using green rolling slats or two stacks of 3 playing cards]. With a lightly oiled blade, cut a strip approximately 5 mm wide x 12 mm long [3/16″ x 1/2″]. Place a short section of a drinking straw on the back of the base where you want the bail to be, and lightly moisten the clay above and below the straw. Pipe a small blob of syringe on top of the moistened areas, moisten the ends of underside of the bail strip, and then form the bail strip over the straw, pressing lightly on the ends of the strip to ensure a secure attachment. Allow to the piece to dry. Make a few more leaves as before and attach them to the dried bail with syringe or paste, embellishing it as desired. Leave the straw in until this step is complete, as it supports the bail and helps prevent it from breaking while you are embellishing it. Allow the decorations to dry, and then sand the bail with successively finer grits of sanding sponges until it is pre-finished to your satisfaction.
Fire the pendant. Once the piece is complete, fire at full ramp to 1472°F/800°C and hold for 1 hour. Air cool or quench the fired pendant.
Finish the metal. Once fired, either tumble polish or hand finish your piece. To add a patina, place a very small amount of liver of sulfur into the Pyrex cup and add about a cup of very warm water. Place it on the cup warmer. Dip the pendant and the chain into the warm solution until the patina is as dark as you want it, and then drop it into ice water to stop the chemical reaction. Use a polishing cloth to remove the patina from the high points of the silver, so that it remains only in the recessed areas.
Add the micro-mosaic. To transfer the glass pieces to the pendant, measure the depth of the inside of the bezel wall. Using glass nippers or cutters, score the height of each piece of glass to mark the height of the inside bezel or a touch higher, depending on whether you want the glass to be flush with or higher than the top of the bezel. Note: To cut the smalti filati and the patterned glass, I use a pair of Lindstrom® cutters with a broken tip. An alternative would be to use the glass nippers available from Glass suppliers all sell glass nippers. I find the sharp cutting edge makes a nice clean break about 85% to 90% of the time. In larger scale mosaic, they use glass nippers, but I found these crush the small glass rods and I have yet to find out what tool was used by the craftsmen who formerly did micro-mosaics.
I use Weldbond® Mosaic Glue rather than the cement grout that was used in traditional micro-mosaics. Squeeze a small puddle of the glue onto a Post-it® note. Starting in the center of the design and working outward, lift a glass piece with tweezers and dip just the bottom of the glass into the glue. Don’t overdo the glue, and avoid getting any onto the tips of the tweezers.. Set the piece of glass in place on the base. Add the remainder of the glass pieces, working as quickly as possible so the glue doesn’t set before you’re finished creating the micro-mosaic. When you have finished adding the design pieces, add small pieces of black smalti filati rods in and around the design pieces to fill the background, cutting the rods to size as you go. When setting the smalti filati, you can move the patterned glass around just a bit as necessary to fill in the background as solidly as possible without force-fitting the pieces. The backgrounds of Venetian mosaics are never filled completely, so don’t worry about 100% background coverage. There always will be some openings too small for smalti filati to be cut to fit. Also, use only fresh glue while you are adding the glass pieces so that they will attach firmly to the metal base. If the puddle of glue begins to set while you’re working, roll up the Post-it® note, throw it away, and squeeze some fresh glue onto another Post-it® note.
After all the glass has been glued is in place, set the piece aside and allow it to air dry for 24-48 hours. Then place it onto the sterling silver chain. The last photos show the front and back of the finished necklace, respectively.
Care and cleaning tips:
Venetian micro-mosaic jewelry must be handled and cleaned gently in order to keep the glass design intact. To clean micro-mosaic pieces, scrub the piece gently and briefly with a soft toothbrush dipped in warm water to which a drop or two of detergent has been added. Rinse briefly and dry the piece with a soft, absorbent cloth (such as an old 100% cotton T-shirt.
Never soak a piece of micro-mosaic jewelry in water or allow it to remain in contact with moisture more than briefly. Although Weldbond® Mosaic Glue is intended to be waterproof, it still can soften with prolonged exposure to moisture, which can allow the glass pieces to loosen.
Planning Your Design:
The chain is as much a part of the design as the pendant, so choose your chain and your pendant design elements to be complementary and harmonious. The bezel on my piece was carved with a rope design to echo the rope chain on which I wanted to hang the pendant. In any pendant design, the chain should be part of the overall design concept, rather than an afterthought. A chain that is simply a “hanger” for your pendant will detract from both the aesthetics and the value of your work!
There are many sources of glass stringers and rods, but here are a few that I use.
www.micromosaics.com – info and pictures of Lauren Hiestori’s amazing work
www.mosaictools.com – home of Miami Mosaics and smalti filati
www.muranomillefiori.com millefiori galore!
www.sundanceglass.com – glass stringers and rods