Metal Clay Tips & Techniques
Below are tips and tricks about how to use Fine Silver Metal Clay, Precious Metal Clay, 950, 960 and Sterling Metal Clay from A to Z. They have been collected from various people who have been working with Metal Clay for many years. The tips are based on actual experiences. If you have a tip to add, please send your tip, name, and website if you'd like to have them included here to: hgage1@ptd.net .
Attachments and Metal Clay Connections in Greenware
Also see blog post: Strong Metal Clay Greenware Connections Have A Common Theme by Holly Gage.
Many connections are used to make Precious Metal Clay Jewelry. Wet to Wet Metal Clay Connections, Dry to Dry Metal Clay Connections, and Wet to Dry Metal Clay Connections. A one size fits all approach doesn't apply, but there are 3 major elements each connection needs, and the different techniques used are discussed for making solid Metal Clay Jewelry.
~Holly Gage, teacher
Balls and Granulation
Even Sized Metal Clay Balls
Start with moist clay and hands lubricatedd with badger balm. Roll out a nice uniform snake of clay under an acrylic snake roller, then cut at even intervals protecting them under plastic until ready to use. I take each section and use my finger to gently roll the section in the palm of my hand first pressing firmly, then lightening up to make the ball round. If the ball has any cracks in it, that means it is too dry, so I put in back in the lump of clay and start over. You have to remember the smaller the amount of clay the quickier it dries out.
~Holly Gage, Metal Clay instructor
It's really easy to make identically sized balls of clay. Choose a straw, and choose a thickness gauge. Roll out a slab of clay to the desired thickness and cut little circles with the straw. Take the little circles of clay and roll them into a ball in the palm of your hand with the index finger of the other hand. I like to find a place in the lifeline of my left hand to roll the ball in. I've made teeny balls with one card thickness and the smallest cocktail straw I have, and larger ones with two or three card thickness using a boba straw. It's a great technique and easy to do.
~Lora Hart, http://www.LoraHart.com
If you have trouble getting rid of cracks in the ball of clay when you roll it in your palms, apply a little more pressure and the cracks will disappear.
~Mary Ellin D'Agostino,
Fine Silver Balls and Granulation
Buy fine silver wire. Cut in identical size lengths according to the size balls you want. Put them in a line on a firing block. Pull out the torch and fire the wire from one end to the other until it rolls into a ball. Remove torch. With fine silver wire, they don't get firescale. The best part is that I've found the bottom of the ball ends up slightly flat. Perfect to keep it from rolling around on the piece you're working on. I usually do up a batch of different sizes and keep them handy for when I need them.
~ Holly Gage, Metal Clay teacher
I make granulation, small silver balls from my saved scrap sanding dust I keep in a container. This is sort of fun too. I make a small pile of the dust on a charcoal or fire brick and point my torch to the top of the pile. Little balls of fine silver roll off the heap at various sizes as the metal melts together. I then sort them by size to use in Metal Clay projects.
Bending Metal Clay and Durability, and Wear and Tear
Torch firing is not a good candidate for bending Fine Silver Metal Clay because the tinsel strength needed is not provided with a torch.
If you provide a long hot kiln firing at 1650º F for 2 hours is your best bet provided there are no fissures, or cracks in your greenware Metal Clay.
Now this one is personal, in my humble opinion, I don't think Metal Clay Fine Silver, 960, 950 or Sterling in general is not good for bending. Many may disagree so take this bit of advice with that in mind. But I've read post after post in Metal Clay forums of reports of breakage. This tells me that it stresses a porous metal like Metal Clay way too much. People say bend it gently or it will break...that to me suggests that the metal is being stressed before you even use the item. With those kind of odds I bend it in the Metal Clay fresh clay stage.
I still think Metal Clay when fired and designed properly art strong and durable, and can be bent or tweaked, but major bending may be asking too much.
~ Holly Gage, Metal Clay instructor
Bezels (Also see Flexible Clay)
Metal Clay Bezel Set Gem
Although there are many ways to set a gem, I really like this method, as you get a clean setting with no cracks or distortion. The thickness of your clay for your bezel is determine by the height of your gem. Measure the height by stacking cards or slats on either side of the gem with the pavilion side or pointed side up. When you can place an acrylic sheet over the top and move it around without moving the gem, you have found the correct number of cards to roll your sheet of clay.
After rolling the Metal Clay sheet, you will cut a donut. The outer donut is to be 1 -2 mm or more bigger than the gem depending on your aesthetic for a thick or thin walled bezel and the size of the stone. This measurement is for smaller stones, larger stones need more clay around it. The inner donut hole should be a bit smaller than the gem. Carefully remove the inside hole, then the outer extra clay (in two or more parts) in that order to avoid distorting the donut. Let dry completely.
Use ae gem bur the size of the stone to refine the inside hole into a conical shaped seat for the gem by twisting the bur in a perpendicular position in the center of the donut hole. Donot twist all the way through. Test fit the gem periodically, so the table is level with the bezel walls.
Wet the hole with a bit of water to rehydrate just the inside of the bezel wall and seat. Let sit for 2 mins. or so to activate the clay to act like "glue" for the gem.
Position the gem pavilion side down and press slightly. Use an acrylic sheet to press the rest of the way, so the table is straight and level with the bezel walls. Double check it is level by holding your piece level to your eyes. No one wants to see a crooked gem! Let the assembly dry. Use a stiff brush to flake off dried slurry that might have gotten on the gem. Also use a very fine pin tool at a 45˚ angle to remove any extra clay around the edge of the stone. Gently, clean the back of the stone as well, but be very careful not to dislodge the stone or you will be repeating
those last steps.
The very last step after full assembly of your piece and before the piece goes into the kiln is to use a twirled up point of paper towel and alcohol to clean both sides of the stone. Be careful not to drag Metal Clay back on the stone during clean up. Metal Clay on the stone can make for an unsightly setting causing an unwanted silver haze or fogginess.
~ Holly Gage, Metal Clay instructor
Use Celie Fago's brass tubes for cutting out bezels in the wet clay for stone setting. Cabs or faceted. Roll out a 1 mm slab of metal clay. Cut a circle out with a large brass tube. Then cut out the center of this circle by using another brass tube with an outside diameter the same as the outside diameter of your stone. Place your stone in the center. . .you know the rest. Or, just take your work and cut out the setting for your stone. After firing it will have somewhat of a flush setting.
~Jerri Duncan
Here's how I teach students to make lump metal clay bezels. First roll a ball of clay larger than the stone. Place the stone right next to the ball, culet side up, and use an acrylic roller or CD case to flatten the ball until the very tip of the culet comes in contact with the plastic. I sometimes stop a bit short. Now the ball is the exact thickness of the stone. Don't use too much pressure when flattening. If the culet presses into the plastic, the setting might be too shallow. Dab a little water on the ball, cover with plastic wrap for about 45 seconds to let the water soak in and hydrate the clay. Put a little hole then divot in the ball for the culet to rest in, set the stone in place and push down until you've properly seated the stone. Then worry about the shape of the bezel.
For square, emerald cut, and triangle shapes, nothing could be easier than just using a tissue blade to cut the bezel. For round and fancy cuts like stars and flowers, just find a straw or tiny round cutter that is about 1 mm larger than the stone. For other shapes I use a combination. For hearts and pears, use a straw that safely clears not only the upper section, but the point of the bottom as well. Then use the tissue blade to cut the V-section. Use the edge of the tissue blade to softly round over the sharp angles and voila, a perfectly shaped bezel. For the heart, I just use a pencil tip or a pin tool to shape the bow. For a marquis shape I do two passes with the straw, one closer to the right side, and one closer to the left. Perfect marquis shape. For a trillion, do a cut with the tissue blade like a triangle, then round it with the edge of the blade. For an oval, simply squash the straw into shape and cut. If there are other shapes I haven't included, I'm sure you can think of a way to make this technique work. Remember to lubricate the inside of the straw, especially if its a thick setting. I sometimes have to put my mouth over the straw and blow the setting out.
Right after I make the bezel, they are fresh enough to place on the base with a little water or slip, and will mold themselves to a very fine texture. Pieces with deep texture probably need to be set with syringe, so that the syringe can fill the voids and give you more contact for a good bond. Sometimes I also set the bezels after they have dried. This has the added benefit of being able to sand the bezel to perfection, or scribe a design on the rim or sides. Then of course you have to use thick slip, or syringe, or both. I have three or four dry stones in their settings that are examples for the students to see, but I could certainly set them on a fresh piece of clay any time.
The stones might shift as you're setting them or possibly as you're shaping the bezel's contours, but then you just have to remember to check that the table of the stone is level before the clay has had a chance to dry.
~Lora Hart, http://www.LoraHart.com
Metal Clay bezels
Make bezels with Metal Clay by rolling out a very thin layer of Flex Metal Clay, (maybe 1 card thin), sheet of clay, cut to the width necessary for your stone + 1 mm for shrinkage, and then set upright and joined (like a ring) on the backing made of PMC. You can take a scan of your stone, or a drawn outline of the stone, enlarge by a factor of the shrinkage rate of the clay you are using, and then trace the outline with a Sharpie onto the greenware backing. Place the bezel clay following this outline on the backing. I then make a copy of the actual stone out of investment and place it inside the greenware bezel before firing. This has worked quite well.
~Laura Hastings
Irregular shaped clay bezels
For stones that can be fired, you can also make a bezel with a stencil (if you don't mind a rather tedious method, that is). The stencil should be the shape you want on the outside, and the hole should be the shape of the stone, and slightly smaller than the stone. Roll out metal Clay thick enough to capture the girdle, cut out your clay shape (with the stencil) over wax paper so you can pick it up. Place your stenciled clay over a sturdy object with a hole. The stenciled clay hole should be centered over the supporting object's hole. This is so the pointed bottom of the stone has somewhere to go. Position the stone over your clay hole and gently push it down level into the clay. The girdle has to be captured within the clay for it to hold. This takes some practice. After it is dry, you can gently sand it and then paste it into position. I drilled a hole into a wood ball for this purpose. The ball's surface creates a convex bezel.
~Gordon Uyehara
Bezels for odd-shaped stones
To make bezels for odd-shaped stones, press the stone into a small piece of clay so that the girdle of the stone is a little below the surface of the Metal Clay. Allow it to dry, then carve away at the exterior until you get the desired look. You can try shaping it while wet, but usually this distorts the clay too much. Remove stone from the dried, carved bezel, and carve/drill a hole behind the stone. This will keep the stone from being forced too far upward as the clay shrinks. Use solo or add to another piece. Replace cleaned stone and fire.
~Mary Ellin D'Agostino
What I would do, is make sure that the stone was bigger at the base like a calibrated cabochon. Then roll out a bit of Metal Clay 3 mm to 6 mm, set the stone on the clay, trace a line about 2 mm away from the stone, and then cut the exact shape of the stone out with your exacto knife. Put the unused Metal Clay away, and set this 'bezel' on whatever base clay you have chosen, and set the stone in place. As usual, clean everything up on the bezel as your design demands, and then dry and fire. Remember it will always depend on the fireable stone you choose.
~Lorrene Davis
Fine silver bezels
Some people size the bezel, insert directly into deep Metal Clay, and fire as usual. Bezel wire is fine silver, so it's compatible for use with PMC without getting firescale. This method works best with small stones. For bigger stones, you'll get distortion as the Metal Clay shrinks around the bezel.
Adding a fine silver bezel to fired and finished Metal Clay piece
After firing the base, place the bezel down where you want it to be. Then I take a pointed tool and scribe a line around the bezel so when you pick up the bezel, you could see where it would be. Then apply a line of Art Clay Paste Type on top of the scribed line. The paste should be twice as thick as the line. Then place your bezel centered on top of the Paste line, thereby having paste on the inside of the bezel and paste on the outside of the bezel – no filling gaps. Art Clay Paste fresh from the bottle with a smoothing agent is the right consistency to smooth itself out, and it looks very clean.
Also see Bezel Setting Like A Pro on Holly's Class page.
~Holly Gage, instructor
Blending and Smoothing
Smooth out the edges of a hole you've just cut (e.g., for a jumpring, etc.), twirl a damp brush in the hole. Smoothing a joint in unfired clay, alternate brushing with oil and water while you're smoothing.
~Celie Fago, http://www.CelieFago.com
Breakage
Pieces break for 3 reasons:
1) They are not engineered well (breaking at joints).
2) The piece or area where it broke, or both, are not thick enough – this is fine silver and cannot be made as thin as sterling pieces.
3) The piece is not firing long enough, or hot enough. The binder in the piece has not been fired out completely and the silver is not completely sintered. A kiln is the absolute best way to fire, then perhaps the Ultralite, Speedfire Cone, and Torch. There are human variables that come into play with all but the kiln. So it may not be the source of heat, but user error as well.
~Tonya Davidson
If you are going to use a torch, propane, or butane, you need to heat until it is a nice orange color (best seen with the lights either off or shaded so you can see the true color). Then you need to fire it for at least 10 minutes at a constant temperature without melting it. Unless you have a fair amount of experience with using a torch, this is hard to do. . .even for those of us who are used to using a torch for soldering. Consider this, when a ring is fired in a kiln, I usually fire it at 1,450°F or 1,500°F for 10 or 15 minutes and then let it cool without opening the kiln door until the temp. is down to around 250°F.
~Ed Dibble (edible)
Also see blog post: Strong Metal Clay Greenware Connections Have A Common Theme by Holly Gage.
Many connections are used to make Precious Metal Clay Jewelry. Wet to Wet Metal Clay Connections, Dry to Dry Metal Clay Connections, and Wet to Dry Metal Clay Connections. A one size fits all approach doesn't apply, but there are 3 major elements each connection needs. Let's talk about what those are and the different techniques used in making solid Metal Clay Jewelry.
~Holly Gage, Metal Clay instructor
Cabs
What is the Cab size to Metal Back Ratio?
There are several factors to consider in this one:
What clay is it?
An alloyed clay 950, 960, Sterling, or base metal can be thinner in general than fine silver.
Stone size and design?
Technically speaking in the stone area you have more substance because you have metal and stone together. It is the metal around the stone you also have to consider. Is it peeking out a little or a lot?
If a little thickness is less of an issue than if it sticks out a lot
If it is a big stone you need a more substantial base to physically and aesthetically support it if sticks out beyond the stone a lot
If the stone is smaller and the base is large you still need substance.
Usage?
In Earrings can be thinner and lighter
In Rings need to hold up to wear and tear, so thicker
In Bracelets also need to hold up to wear and tear, so thicker
These are just estimates but you get the general idea
Small piece > 15 mm
-Alloyed clay no less than 2 playing cards
- Fine silver - 3 playing cards
Medium piece > 30 mm
-Alloyed clay no less than 3 playing cards
- Fine silver - 3 playing cards
Large piece < 40 mm
-Alloyed clay 4 playing cards or more
-Fine silver - 4 playing cards or more
Coils and Snakes
(Also see Syringe)
Cracks in a coil: after rolling out a coil (snake) moisten all sides with a damp brush and allow a moment (or two) for the moisture to soak in "before" you try to manipulate it. This will keep those nasty cracks from happening.
To get a smooth even coil: roll the Metal Clay into an oval in your palms (with no cracks). Then use a smooth flat surface to roll out the coil – a piece of Plexiglas, the bottom of your Badger Balm, a brass plate, or whatever. Apply just enough pressure to keep elongating the coil. Too much pressure and you will just squash it. This is great for people who have trouble making even coils using their fingers and hands.
~Mary Ellin D'Agostino
Using an acrylic sheet with a handle glued on. Makes rolling out an even snake a dream.
~Lorrene Davis
Use a clear CD case lid as a roller, instead of plastic acrylic. I just trimmed off the 'tabs' which attach it to the rest of the CD case and then hold the whole thing by it's upper edges when rolling out coils.
~Jerri Duncan
Cork Clay
When working with cork clay, ramp up the kiln slowly to give the cork a chance to burn out, which will happen around 800°F or so. This will prevent overheating, which can occur if the cork is still burning at higher temperatures, resulting in cracks or melting. Ventilation is highly recommended.
~Holly Gage, Metal clay teacher
Creativity
Try this exercise, it's a great method of evolving your Metal Clay and Jewelry ideas. Sketch 5 drawings of your ideas after brainstorming a list, motivation words surrounding an idea or concept. The first will probably be nice, but the 5th will have taken you to a whole new creative place. The video below illustrates the concept.
Jewelry Design: Evolving Your Ideas with Master Metal Clay Instructor Holly Gage
~Holly Gage, Metal Clay teacher
Also Holly's classes on building your design skills
Designing with Intention
The Art of Designing a Signature Jewelry Line
Distortion, Curling Greenware (Also see Warping)
Flipping the piece every so often on the heat source will prevent warping and curling of Metal Clay. A dehydrator works well as long as the Metal Clay pieces sit directly on the shelf so the air can circulate evenly.
But how to fix it in the greenware stage if it does warp?
I put it in a humid place -- a mini humidor, a container that has a wet sponge in the lid, or a container I spritz with water on the lid. I put the piece inside for 30 mins or more. As the piece absorbs the humid air try testing it to see if it is ready to be flattened out. Don't force it and put it back in if it needs more time. (See Video: How do I Rehydrate, Reshape, or Fix Warped Greenware Metal Clay? With Holly Gage under Warping)
~ Holly Gage, Metal Clay instructor
Drawing On Bone Dry Metal Clay
You can draw with a pencil directly on the clay for guide lines before you carve, or lay down a design, or syrringed clay. Use a light touch and a regular number 2 pencil.
Drawing or Scribing Lines on the Surface of the Metal Clay with a Pin Tool
(Also see Engraving)
Drying Out or Dried Metal Clay
In general, if you see cracking edges when you start making your impression, the clay is too dry. So ball it up immediately and knead it with a bit of water in plastic wrap, let it sit for a minute or two, and add more water a small bit at a time if more is needed. If you can make a ball, and squash it in your fingers and see no cracking, your good to go.
Totally Dried Metal Clay. Poke holes in the Metal Clay and wet it all over (preferably with distilled water which doesn't get moldy), and wrap it up in plastic and let it sit for quite a while. Keep adding more water and rewrapping until it starts to bend. Eventually, you will be able to start to knead it. At that point, only add water a bit at a time so that you do not overdo it. Sometimes I get a pretty good consistency that way, and other times I add a bit of gel glue toward the end of the process to get a better consistency. I don't think it ever will get like it was fresh from the package, but you will get something very usable.
~Holly Gage, Metal clay teacher
If the clay seems to dry out in your hands quickly and you have dry hands. . .go wash your hands in warm water, getting them good and hydrated. Then apply your olive oil or balm to lock the moisture in. Very dry hands can pull the moisture from the silver clay and greasing up dry hands just gives you dry greasy hands.
~Mary Ellin D'Agostino
CoolTools.us – Mardel Reins ClayMate hand cream. In addition to keeping my hands shielded, it seems to keep the clay from drying out too fast.
~ CoolTool.us
Squirt some syringe clay onto flattened lump and fold that in as you knead. This works well to help rejuvenate the lump because it not only adds in pristine clay, but the syringe clay has more moisture.
~Gordon Uyehara
To Dry Out Metal Clay
If I'm in a hurry, I swear by the coffee cup warmer or the smallest Salton 6 x 6 size glass warming plate. If the piece is to remain flat (like a charm) however, you need to keep turning it (every 15 mins. is my rule) carefully to avoid warping. Don't forget the mirror test to check if it's dry. . .if you lay the piece on a mirror or wide tissue blade, anything shiny. . .and pick it up, if you see any condensation or even a hint of moisture, put it back on the warmer until you don't!
~Sarasota Sarah
A dehydrator is great because it dries it evenly from all around, and faster. Better than a coffee warmer, is putting it in the oven at 325°F for 10 minutes, but I realize that you can use a mug warmer without getting up from your work area.
~Elaine Luther
Earring Wires (Also See Embedding Wire or Sheet Metal in Metal Clay Below)
To fasten ear wires to earrings:
1) Push in while wet, or attach with clay when dry, a length of 20 gauge fine silver wire.
2) Attach a commercial earring post. I use Stainless steel posts with a pad.
Again, push into the wet clay or attach with more clay to a dry piece. Make sure the base is well covered. I brush some paste onto the post to prevent it from turning black.
~Alcina Nolley, http://www.alcinanolley.com
Embedding Wire or Sheet Metal in Metal Clay
See blog post: Can You Combine Fine or Sterling Silver Metal Clays, Different Brands, or Fabricated Components? by Holly Gage
Among other things, the article answers if you can add Fine Silver and Sterling Silver Wire or Sheet or Pre-fired Metal Clay parts to our pieces
~ Holly Gage, Metal Clay Instructor
Any advice to make sure the sterling silver doesn't get brittle? Yes, fire at the lower temperatures – try 1,290°F for 10 minutes. In addition, if you raise a fine silver surface on the sterling before firing, you don't have to clean it up after firing. To do this, alternately heat the sterling (with torch or in kiln) until it turns dark and then pickle (in jeweler's pickle, citric acid, or vinegar) until it turns white again. Repeat 2-3 times until it doesn't darken when heated. Then embed and fire. The hotter/longer you heat sterling, the more brittle it will become.
~Mary Ellin D'Agostino
To safely fire sterling ear wires in place, don't let the temperature rise above 1,300°F. Sterling silver melts and starts degrading at a lower temperature than fine silver.
~Lora Hart, http://www.LoraHart.com
The hotter/longer you heat sterling, the more brittle it will become. This is the main reason I do not use sterling. When you are using the silver depletion method of bringing a fine silver coating to the surface of the sterling, you are depleting the copper alloy in the sterling silver. The copper was added to the silver to make the silver harder. . .so it wouldn't bend as easily as sterling. When you use the depletion method, you are degrading all of the sterling because you are REMOVING THE COPPER at the surface. In addition, when you are using the depletion technique you are lowering your profit margin by:
1) Adding extra time to the construction of the work;
2) Using sterling. . .the work is now not all pure silver, and must be marked as such;
3) A lot of women are allergic to the copper in sterling. The depletion method is good at the point of sale, but iffy with a lot of wear which could affect later sales.
This is a way cool method on large items. . .I have used it many times. All of my tests of firing 19 to 20-gauge sterling wire at a low temp of 1,110°F - 1,200°F has created a very brittle bunch of ear wires. It might not break right away, but it will. . .I promise. So, I have taken to using fine silver wire in my ear posts. Now, the long, artful, wires do get misshapen with use. . .so I steer away from using .999 in some of those instances. That is the only time soldering could be useful for me. But, I rarely solder. I don't like the look of the back of the earrings of puddled solder that discolors, and I don't like to clean messes on the back. I suggest doing your own testing. Try firing sterling wire in the kiln or torch it. Then do the bend test. Count the number of bends it takes to break the fired wire in relation to the number of bends for the unfired sterling. We, women, are hard on our jewelry. Just my point of view.
~Lorrene Davis
Fine silver wire will be softer than the sterling silver, but it certainly can be fired with the Metal Clay to the strength needed to fully sinter the Metal Clay. For ear wires, I have yet to have one break or bend significantly in 21-gauge wire. It certainly will not become brittle and break off. I've used fine silver wire embedded in Metal Clay with success for a couple of years now and no complaints.
~Karen Rossman
It is important to creating a mechanical inner link so the Metal Clay shrinks around the wire, and prevents it from coming out with time if nothing were done. My experience is that it does at one point start to move, depending on the design used, such as ear posts for example. Some people make a loop at the end of a wire which is to be embedded, an omega or a figure 8 in order to lock the wire in the clay through the shrinking. This method does however, use up a lot more wire, and when the clay shrinks but wire doesn't, your design can get distorted. So to avoid this extra thickness in the clay, which would be really obvious after firing, I cut my wire just about 1/2 cm longer than needed and hammer it, spreading the ends flat. The clay shrinks around that, preventing the wire from slipping out. Since it's flat there's also no extra width or any major warping. The hammered ends of sterling silver wire when embedding it in Metal Clay, create the lock and key system, using less wire and without an outer bump, looking like it was soldered with no trace of the wire whatsoever since the wire is flat inside yet rounded outside. This is how I embed almost all my wire.
~Angela B. Crispin
Here is the skinny on Embedding Fine Silver or Sterling in a piece. You will get little if any distortion if embedding something small such as an eyelet. If there is a large area connection you may get some distortion since the wire doesn't shrink and the Metal Clay does.
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Embed Fine Silver Wire directly in Fine Silver or Sterling Metal Clay by notching the connection that is buried in the Clay so the Metal Clay can make a mechanical connection. Fire as normal.
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Embed Sterling Silver Wire directly in Sterling Silver Metal Clay in the same manner. Since you will be firing in carbon fire as normal
Engraving on Metal Clay - Greenware Stage
I often let the clay get bone dry and draw on the clay with a pencil as a guide. Then I take my pin tool and "lightly" scribe a "starter" line. I say lightly because this will set a grooved path for your pin tool to follow as you go over the lines a couple times making it deeper with each pass. I don't like to go deeply the first time around for several reasons: 1) If I go lightly and I don't like the placement of my letters, I can just sand it out vs. corrective surgery with my paste; 2) I have better control of the line quality.
I like to hand scribe because things are in my own handwriting and I can better control line weight and quality.
To make wider lines, on a second or third pass I'll angle my tool a bit 15° degrees outward - not straight up and down anymore, but how you would angle a pencil when you are writing. This opens up the line a bit by beveling the edge.
To clean up scratchy looking lines, I'll use a fine brush with a tiny bit of water to smooth it out.
I think varying line weight and depth can help focus your eye to one part of the piece or other. Thick deeper lines add emphasis while light thin line are more subtle.
Another method that works for me is wetting the piece from the back and letting it soak in until dried enough to flip over to work on the front. What's the point? Well, if I were to wet the surface in the front, it reactivates the clay and it gets "pasty," and then my tool would drag the paste, and the line would not be clean. BUT, if I wet it from the back, the front still has a dry "skin" on it, and my tool can go in deeper and more smoothly without surface drag. I'd experiment with this one because I had to get a "feel" for it before it worked for me.
~Holly Gage, instructor
Finishing
(See Prefinishing, Polishing, and Tumbling)
Prefinishing. Burnishing the greenware before firing helps compress the dry clay a bit. Removes some of those air spaces created when the water evaporates. . .also enables one to have a head start on a mirror finish.
Finish as much of your piece as you can before you fire. Don't be in a rush to get it to the kiln. File and file, and then when you think you are done, file some more! Don't forget #2 when filing.
~Jerri Duncan
Mirror Finish. Greenware. Sand smooth using sponge-backed sanding pads. Work your way up from coarse to fine going through 1,500, 2,400, 4,000, 12,000 grits. Be sure to wear a magnifying visor while you're working. That will help you spot any problems. If you notice any divots or scratches along the way, fill them and re-sand. It's much easier to fix in this stage than after it's fired.
Gently burnish with an agate burnisher. I believe you get a better finish this way, but it also serves another purpose. Any little scratches and divots you might have missed will become apparent after you burnish. If you need to go back and fill anything, hit it with the 2,400 or 4,000 grit sanding sponge again first. Paste and syringe don't stick well after it's been burnished, so you have to rough it up again.
Once it's completely free of all marks and burnished smooth you can fire it.
Post Firing Finishing. Brush with a soft brass brush and burnish with an agate burnisher, taking care not to scratch the surface. Sand with wet/dry sandpaper going through 600, 1,000, and 1,500 grits. Rinse and alternate direction of sanding between each grit. Begin polishing with Tri-m-ite polishing paper, working your way through Green, Gray, Blue, Pink, and Mint in that order. I don't bother with the white as I find it does more harm than good. Again, rinse and alternate direction of sanding between grits. Finish up with Wenol metal polish, buffing with a super soft flannel cloth.
~Pam East, http://www.pinzart.com/
If you find a divot when polishing after firing, you should fill it and re-fire instead of trying to polish or sand it away. You will save yourself loads of time and trouble!
~Mary Ellin D'Agostino
Firing Metal Clay
(Also see Holly's blog post "Kiln Firing, Sintering and Silver Metal Clay" Understanding how Silver Metal Clay fires and sinters is the key to your project's success.)
It’s all about the sintering.
Understanding sintering basics: Fine silver Metal Clay is made up of particles of fine silver, and an organic binder, and water. The binder and water are what allows the silver to be flexible and moldable. It is the ability for the binder and water to be removed, and the remaining fine silver particles to sinter together and form a solid piece of metal, that is the magic of Metal Clay. The binder and water are removed with intense heat, either by the heat of a torch or kiln and other devices on the market. Next, the small particles of metal sinter together. My definition of sintering is to form a coherent mass by heating without melting. In this case, joining particles of silver to create a solid mass.
Key Concept: Fire as hot as you can and as long as you can allowable for your project for the strongest most durable end product. 1650°F for 2 hours PMC; 1650°F for 2 hours Art Clay.
The sintering of the metal is the key element in the process. At the lower temperatures of the firing schedule, the silver particles sinter together, but it is NOT a full sinter, leaving microscopic spaces. At higher temperatures, the metal DOES fully sinter and becomes a more dense material. Ok, what does this mean? This means at all levels of firing on the firing schedule you will get a hard piece of metal, however, at the lower temperatures, the metal will not hold up to the same amount of abuse, wear and tear, and stress as a piece fired at the higher temperatures. Pieces fired at the highest temperature not only fully sinter, but the metal can actually gently bend without breaking. ( See Bending Metal Clay) There are reasonable uses for some of the lower firing temperatures such as glass, gem, and fire-in-place inclusions, but the usage of the final item, construction, and design should be considered. For instance, earrings and pins get less wear and tear than rings, so firing at low temperatures for a ring would not be prudent. Also, delicate parts or construction like filigree or prongs need high firing also. In fact, I never fire a full piece at the 1110°F firing schedule since my “personal” feeling is the strength is compromised. I hear too many reports of breakage and have experienced some myself in my newbie days. There are exceptions to every rule and I have used a successful short firing in a two part firing where you are adding a flat object to a fired base, for example adding a door to secure glass in the cavity of a piece, or adding a low fire bezel set stone.
I was told firing at 1650°F for 15 minutes is almost as good as firing for 2 hours, is this true?
There have been tests conducted by the PMC Guild that suggests when firing at 1650°F for 15 minutes compared to a 2-hour firing, there was a small advantage to firing for 2 hours, but the difference was very small of 2%. For this reason, teachers may choose to use the shorter firing time during a class setting without compromising the strength of the given project.
So Why A Full Firing Schedule?
There are factors that need to be considered before selecting your firing schedule. One firing schedule does not fit all projects:
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Thickness of the clay. Is your project thick enough to hold up to wear and tear or should you fire at higher temperatures to avoid breakage?
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Manipulation and use of the end item. Will the piece need to be worked further requiring shaping, bending, or hammering? Will it get a lot of abuse such as a ring or a bracelet would?
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Are there inclusions? Are you firing in place glass, gems, or inclusions that require a lower firing schedule? If so, you may need to alter the clay thickness, design of the piece, and consider the stress on its end-use. A new sturdier construction plan may also need to be considered.
The two brands of Metal Clay, PMC and Art Clay, work much the same way and they both provide a firing schedule for each item in their product line. However, one thing they forget to mention is that the lower firing clays can be fired at higher temperatures. All Silver Metal Clays can be fired as high as 1650°F for 15 minutes to 2 hours (Except Phometheus). Let me again emphasize that all projects should be fired as high as they can with consideration of the inclusions for the strongest most durable results.
~Holly Gage, instructor
Flexible Metal Clay and Additives
(Also See Glycerin Below)
Olive Oil
I use olive oil rather than glycerin. Rub a thin layer of olive oil onto the plastic or teflon sheet, roll out the Metal Clay (for the bezels I make, they are usually two to three cards thick), let the Metal Clay air dry (very important!) It will absorb the olive oil as it dries.
If the Metal Clay is dried by quicker methods than air drying, the flexibility of the bezel wire will be compromised.
The trick to using the olive oil is to get the right mix. Same as with glycerin, if too much is added it will change the consistency of the Metal Clay and would compromise the strength of the bezel. I usually dab my fingertip into the olive oil and rub it onto the plastic sheet. This is enough to create a thin, even layer of olive oil, which in turn is enough to soak into the bezel wire. To make sure the olive oil is spread evenly, hold the plastic sheet up so light reflects off of it. If you see some of the plastic showing through then add just a touch more.
I have to confess, I've been using olive oil successfully so have not made much of an attempt to experiment with the glycerin. Although I do have a bottle and will eventually use it. So as far as comparing the strength, Mary Ellin's explanation about how glycerin might affect the
strength of Metal Clay would also apply to olive oil.
~Jeanette Landenwitch
Gems
Flush Set Gems with a Gem Bur
- Simply make a hole in the base
- Use a gem bur the same size as the stone
- Wet the inside of the bur setting (WAIT 2 mins)
- This will make a self slip
- Place the gem in the setting and level as best you can with a tool
- Take your snake roller and press the gem table flush with the piece
-Let dry
- Clean up both sides from the extra slip if needed and then clean with alcohol
The slip will hold it in place
Being set flush with the table of the stone will allow it to shrink and push it up just a hair
Flush Setting a Series of Fire in Place Faceted Gems in Metal Clay
Each gem needs enough Metal Clay around it to hold it in place. Picture an individual bezel and the metal required to hold it in. In this case, I would have at the "least" a 1 mm to 2 mm around stones that are relatively small. So between stones, you would need double that.
The issue is shrinkage. The stones won't shrink and the metal will, therefore you will also get more distortion in a cluster like that if enough space between stones is not given. Most metal can be hammered flat after, except where you have the gems.
Finally, an azure, a hole behind the stone, is preferable especially for transparent gems where you can see the kiln white right through the gem giving the gem a cloudy effect, so the hole gives you brighter result.
~ Holly Gage, Metal Clay teacher
Glycerine
(Also See Sheet Metal and Wire Out of Clay)
Extend the working time of PMC by adding a few drops of glycerine. Make slow dry clay by adding 2 drops of glycerin to 20 grams clay, mist
with water, mush in plastic wrap and wait an hour.
It's true that you can extend the working time of PMC by adding a few drops of glycerine, but here is a trade-off: Extending the working time is appealing, but when we've finished our work, we want the clay to dry and harden. Because the pieces never really dry, they are fragile during assembly and when moving to the kiln. The other downside is that glycerine-treated PMC will be difficult to bind to itself. If you are constructing pieces with several layers or elements, you'll have trouble making these parts stick together.
~Tim McCreight
Smear on a thin layer of glycerin then let it dry. No mixing it in. The glycerin seeps into the wet clay and does the same great job of making it flexible when dry, but without the work of working it in.
~Celie Fago, http://www.celiefago.com
Once you add the glycerin to the clay and get it all worked in the Metal Clay, it is back to it's original clay-like state. At this point you can roll it on textures or do whatever you do to regular clay. But when it's dry it will be very flexible. Really cool.
The clay is totally dry but still flexible. I dried my piece overnight and also on a hot plate after adding some paste to some low areas and the clay with the glycerin was still very pliable.
~Paige
While there are many interesting and desirable affects from adding substances like glycerine to Metal Clay, such additions will not make the end product stronger. They affect the working characteristics of the clays before firing.
They MAY also cause a more brittle or "weaker" end product after firing. Diluting your clay with other substances spreads the metal particles further apart and the end product is likely to be more porous and brittle than the original formulation of the clay. Ever notice that a piece made from paste needs to be thicker than one made of clay to achieve the same strength level? Ever notice that a strand of syringe (no tip!) when fired is not as strong as a strand/coil made by rolling out clay to the same thickness? These more dilute forms of metal clays are not quite as dense or "strong" as the clay type. Please keep this in mind when you create pieces using additives. You may find that you need to make pieces a bit thicker or apply them to base pieces of unmodified clay or other materials. Just be aware of the potential ramifications.
~Mary Ellin D'Agostino
Gold
Keum-boo. Consider keeping a stainless steel burnisher exclusively for this purpose and don't polish it when it starts to oxidize. The oxidation will help keep it from sticking to the gold.
Aura. Use a silicone color shaper to stir and/or apply Aura 22. Let what remains on color shaper dry; it will flake off and you can return it to the jar without losing any of the gold.
~Margaret Schindel, https://feltmagnet.com/crafts/preciousmetalclay
PMC 22K Adhering or Fusing to PMC3. The gold clay and silver do not bond. It appears that you need to capture the gold with syringe, paste, or do a PMC Rivet in order for it to mechanically attach itself. If you imbed it, there doesn't seem to be a problem. However, surface bonding doesn't work. I've tried just about everything (silver paste underneath, etc.)
So my suggestion would be for you to drill a hole where you'd like to attach the gold. Then work some of the gold into the hole with your clay shaper. Then make a bit of it into a paste and attach the ball to that.
~Tonya Davidson
What about a gold-to-silver skinner blend like the ones in polymer clay? Do you think it would work? Yes, this would work as you are actually creating a physical bond between the two types during the blending.
~Mary Ellin D'Agostino
Problem: During finishing several of my gold components came off.
You are probably running afoul of the difference in shrinkage between the gold and the silver. There is about a 2+% difference in the shrinkage of the 22K gold and the silver. You need to make a little more of a physical bond between the clays. Thus, if you want to attach a smooth gold clay ball to a smooth silver clay surface, what you actually need to do is make a physical connection between the two types of clay. Either set more deeply in the silver (like setting a stone) or make undercuts or angled holes in the gold, fill them with silver clay, and attach to the silver base such that the silver will make a locking join to the gold.
~Mary Ellin D'Agostino
Hollow forms
( See Slumping and Distortion After Firing)
If you use cork clay as a support to build your form on, when firing, ramp up your kiln slowly to give the cork a chance to burn out, which will happen around 800°F degrees. This will prevent overheating which can occur if the cork is still burning at higher temperatures, resulting in cracks or melting. Ventilate well since the cork gives off fumes.
~Holly Gage, Metal Clay teacher
Whenever you are using cork clay for your hollow form, be sure to thoroughly dry the piece before firing. So before firing in the kiln, I stick my piece in a small convection or toaster oven and heat to 250°F. If I've been working fairly wet in the final steps, I'll hold it at that temperature for about 30 minutes. Cork clay can absorb moisture from the silver clay. It's the moisture that causes real problems in firing. A piece may seem dry, but the moisture has wicked to the interior. An extra drying will not hurt anything and can ensure good results! Just be sure to be careful when removing it from the oven, it will be hot!
~Kathy Davis
How to help a square or circular open-ended box not slump. The walls are no larger that 1 1/4" high or wide, and are made of 5 card thick PMC3. They are bone dry and sitting in a nest of vermiculite. I also filled one of them half full of vermiculite but it still didn't work. I kiln fired for 10 minutes at 1,650°F.
Try filling all the way with vermiculite or fiber blanket. This should help. You don't need to worry about vermiculite expanding as it will simply move out of the box if it does. With fiber blanket, you would want to tuck some in – but not too tightly (or too loosely). I would fire with the opening facing upward to minimize the slumping aspect. You could also try heating the kiln more slowly (assuming you have been using a fast ramp speed). Some people bury their items entirely in the vermiculite.
~Mary Ellin
Kiln Firing
(Also See blog post: Kiln Firing, Sintering and Silver Metal Clay by Holly Gage
Understanding how Silver Metal Clay fires and sinters is the key to your project's success. This article will give you an understanding of how it all works.)
~ Holly Gage, Metal Clay instructor
Klutz Tips
Cleaning Up. A hand-held restaurant table sweeper that can be purchased at a restaurant supply store is great for picking up things that fall on the floor. It consists of a white hand-held box with a rotating brush and a lid. After I drop my pearls, beads, little balls of clay, whatever, I run the sweeper over the area, then I flip the device over, remove the lip, and I can retrieve all of the items I lost.
~Holly Gage, teacher
For delicate pieces that you need to continue to work on, but keep breaking either because you're a klutz or it is delicate. Repair the break, and finish that component, and put in a craft only toaster oven and bake on a high temp anywhere between 300°F - 500°F degrees. It makes it nice and sturdy. The downfall is you can not do any more pre-finishing on that part, so make sure you do all greenware sanding before the toaster.
~Holly Gage, teacher
Replacing a Cracked or Ruined Gem in a Finished Piece (See Setting A Gem in a Fired Metal Clay Piece with Oil Paste)
Use a weighted cup for your water. I was using an old plastic pill container and spilled it at my bench more times than I'd like to admit, however I have never spilled my new and improved container that is weighted on the bottom.
Leaves and Paste
To prevent curling. A good rule of thumb for leaves of average pendant size – approx. 4 cm x 2.5 cm – is to weigh the leaf periodically as it is being pasted. Should weigh at least 3.5 grams before firing, and make sure edges are thick, and pronounced middle ribs are well covered! Try and find leaves that have "substance" – in other words, they must not be juicy soft like spinach! Try mint leaves for terrific texture, and wonderful smell when fired. When starting out to do leaves, avoid oily ones like geraniums until you know how to get over the fact that they DON'T like being pasted – the oils repel the clay. Hairy leaves are also a big problem – these are best rolled – impressed – into the clay to give the vein texture. Look for tiny leaves to paint and keep for adding to other creations, often can make a so-so piece into a winner!
~Dragonscm
Many leaves curl during firing. This seems to be due to the thickness of the silver clay paste (thinner pieces curl more) and the type of leaf coated. Some types of leaves tend to curl more than others when burned. Uneven coatings of silver clay could also add to the curling effect. As long as the leaves are not too-too thin and were fired at the higher MC temperatures, you can gently uncurl them with your fingers or other tool. If they start to crack, you should stop. In that case, you could either re-fire for longer/hotter or add more clay and refire for longer/hotter. If they were only fired at low fire MC temperatures, you should refire at a higher temperature before trying to uncurl them very much. I hope that is reasonably clear.
~Mary Ellin D'Agostino
The problem with slip-coating is not in the leaf. . .it's in our natural impatience to want something beautiful NOW! LOL! Successful slip coating is best accomplished with: 1) A totally dried organic material; 2) Absolute minimum of 10 coats, graduating the slip from thin to medium thickness; 3) Totally drying between coats, thus indicating a period of a week to 10 days to be absolutely sure you've applied enough coats, drying properly. . .curling will be minimal.
~Sarah Triton
Someone mentioned using the food wrap that has a slightly sticky surface. Place the front of the leaf on the sticky side and press firmly together. I tried that with a leaf and it worked great. No curling while pasting and it fired great.
~Lorrene J. Davis
Lines
(See Engraving)
Liver of Sulfur
Keep a small film container full of dry LOS so that you do not have to keep exposing your large container to light and air just to get a single piece out each time.
~Gordon Uyehara
Liver of Sulfur - Beauty and the Beastly Smell by Holly Gage is a comprehensive article that has recipes and answers to some of the most frequently asked questions people have about using LOS. With a bit of knowledge under your belt, you will feel much less intimidated to use LOS, and once you realize that LOS patinas CAN be removed, you will feel free to experiment without the worry of ruining a piece you spent hours creating.
~Holly Gage, Metal Clay instructor
Mirror Finish
Here is my process. First of all, you will get nicer "mirror" finishes with the low fire clays than the high fire ones, because the silver in them is finer and the particles that make them up are closer and more uniform.
I start with the 3M polishing papers in the greenware stage. I work the green (coarse) the most and get all the imperfections and divots out. Then I proceed to each successive finer grit. I do not proceed without getting ALL the divots out, because if you do and think that the next grit will get rid of it, you're wrong, it will only put a shine on the divot. Each successive grit should be worked in the opposite direction, i.e.: if you are working horizontal strokes with the green, you should work vertical strokes with the grey (next grit). What this does is get rid of the coarser sanding strokes of the prior grit.
After I fire, I use the Advantedge rubber polishing wheels (Rio). I use the blue (fine) and the pink (very fine). I rarely use the black (medium) unless I have a really bad divot that shows up after firing. The black can be pretty aggressive. I also use the radial bristle brushes (Rio) to get in the nooks. These all go onto a dremel or flex shaft, and you have to remember to keep them moving to avoid making grooves and drag lines in your work. You'll want to switch your direction often to avoid that.
~ Holly Gage, Metal Clay instructor
Molding
There is a good 2-part mold material called Amazing Mold Putty. You can get it at Michael's and online. I really like the details.
~Judi Weers
I use Alley Goop. That has been my favorite for a long time. Alley Goop is only sold online as far as I know.
~Jean Melton
I really like the two-part mold mix they have at Art Clay World – very easy to use, it is "soft" rubber. Second runner up if a harder rubber mold is needed, is the Sculpty mold maker, which is 1 part.
~Liz Hall, http://www.lizardsjewelry.com
There is a two part cold molding compound called Belicone Rubber which sets up completely in about 30 minutes. from Rio Grande (online and catalog). Also, there is Sculptey Make and Bend, which you mold and then bake. The thing I like about this, is there is no time limit. So a technique I have developed is similar to tear away technique, but instead of a photocopy, use a pencil drawing. With Sculptey Bake and Bend, the result is slightly different, you get the pencil drawing transferred onto the Sculptey and the pencil lines are raised – hard to explain, but it is not grainy and flat like in the regular tear away technique. You can bake it as is or use the pencil lines as a guide. Then you have all the time you need to take a tool or stylus, and push the Sculptey around and make low relief areas, textures, lines, whatever – remember you are working backward, and any area you push in will be raised.
~Holly Gage, Metal Clay teacher
Mixing Clay Types and Brands
See blog post: Can You Combine Fine or Sterling Silver Metal Clays, Different Brands, or Fabricated Components? by Holly Gage
Three factors need to be considered when determining if Silver Metal Clays and manufactured components can be fired together including kiln firing conditions, firing temperatures, and shrinkage rate of the Metal Clay
.
~ Holly Gage, Metal Clay Instructor
When using two different types of clay in one project, always fire at the higher firing temperature of the two clays. This would also hold true when using the two different brands of Metal Clay, Art Clay and PMC.
~Holly Gage, Metal Clay Instructor
Knead together well. The shrinkage of PMC Standard is quite a bit different. Could create some interesting effects if not mixed thoroughly.
~Gordon Uyehara
Photographing Jewelry
See Holly's blog post: How to Take Better Jewelry Photographs on an iPhone or Cell Phone by Holly Gage
Learn simple jewelry photography best practices when using your cell phone. You will take clear beautiful pictures with an inexpensive lighting set-up, and then learn how to edit photos right on your mobile phone.
Photopolymer Plates
With polymer plates, you can make your own original designs in a permanent plate enabling you to texture your Metal Clay with your own original patterns like no other.
A Photopolymer plate is steel or plastic backed plate with a light sensitive polymer layer. They arrive in a black-out envelope to keep out light and each plate is covered with a clear protective sheet. After being exposed to UV light, the polymer plate will hold the impression of your artwork.
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Create a black and white pen and ink drawing and transferring the artwork to overhead project via a photocopy, be sure to match the sheets to your type of printer. They must be crystal clear. For a crisp image, the the drawing must be dense and black.
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All black areas of your artwork will end up being raised on the Metal Clay
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Expose the plates in the exposure frame by placing the printed side of your artwork down on top of your photopolymer plate. The exposure frame coming with many kits has the following items, all of which you can easily assemble on your own. Sandwich your plate in the frame in the following order:
- The glass.
- The image. Print side down is preferable for the image unless you are creating a flipped mirror image.
- The photopolymer plate, polymer facing up.
- The foam sheet to even out the pressure and contact between the artwork and polymer plate.
- A sturdy backing of masonite. -
Hold the sandwich together with the bulldog clips on all 4 sides being careful to steer clear of the artwork
and plate. -
Exposing the photopolymer plate to the UV light and washing out the iimage.
UV lights need to be tested for exposure time. You can do this by making a test strip by covering portions of the artwork during UV exposure. With black paper, cover a quarter of the artwork. Move the paper over to cover 1/2, then 3/4 of the artwork in 20 second intervals. Keep track of your time on a piece of paper. A good exposure time is when the plate washes clean in one of the test areas. This is the exposure you will use for all your work. You only need to test once.! -
Expose the plate for the proper time by turning on the UV light and timer. When the timer is up, turn the light off. Remove artwork.
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Using a soft brush and a warm tub of water gently scrub in all directions. As the polymer is removed exposing the plate backing, be careful not to scrub off the tiny details. I usually leave a super thin layer of polymer on the bottom as not to lose those tiny details.
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Let excess water drip off the plate, and then dry the plate with a blow dryer refraining from long exposure to the heat.
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Cure the plate under the UV light for 1 minute.
~Holly Gage, instructor
Also see Holly's classes featuring photopolymer techniques:
Whimsical Critters
Jorviking Viking Purse
Jewelry That Rocks
Photopolymer Plates Textures
Video: The Secrets for Making Two Photopolymer Plate Textures in Metal Clay with Instructor Holly Gage
Master Metal Clay instructor Holly Gage explains the different effects you can get with photopolymer plates, which are used for creating interesting textures on Precious Metal Clay. Traditionally, dense crisp images and solid lines are created, but with a bit of experimenting, Holly uses alternative methods to get a low relief modeled effect which gives a beautiful more subtle texture.
Placeholders
Used for stones that cannot be fired in place.
Options:
Delight Paper Clay burns away, this can be used as a temporary armature.
Creative Paper Clay does not burn away, this is stable enough to chip away if need be or removed and used again if thick enough.
Uses:
It can be used as a placeholder for a fine silver bezel embedded in the Metal Clay. It helps keep the alignment of the bezel and also is helpful for minimizing distortion caused by Metal Clay shrinkage during firing. You can gently pack the bezel with the paper clay or mold a duplicate of the stone. I recommend you dry it completely, but once, I did it in a hurry and it was only 3/4 dry and it worked. It can also be used as a placeholder for ring sizing.
Pros:
Easy to mold and it can be shaped and formed in a ready-made form or mold. Can be dried on a hot plate. No shrinkage. Can survive the pressure of shrinkage.
Cons:
Limited use of 1 to 4 times. It can dry out. Kneading water into it will revive it as long as it is not bone dry. Put a damp paper towel in the plastic package to keep it moist.
~Holly Gage, Metal Clay teacher
Plaster of Paris
Plaster of Paris is used to make a model of the stone. . .it's cheap and you can quench the piece right out of the kiln, and the P of P dissolves. Can’t be used with a torch, though. Do it outside, it's messy to mix up.
~Sarah Triton
When it is difficult to get an accurate model of a stone through carving – something pourable like investment or plaster in a mold is much easier to work with. I found carving much too time consuming and difficult to accurately reproduce the stone.
It also depends on the plaster. Some brands/types may work OK, others will not. I've had some pretty dismal failures with plaster. For example, when using ring patties made out of plaster, the end result was a smaller ring than the desired size – the plaster did shrink.
~Mary ~Mary Ellin D'Agostino
Tim explains placeholders in his book "Working with Precious Metal Clay." You duplicate the stone in its original size (shape, height etc.) in plaster. He suggests to pour the plaster into a paper cup the height of the stone, but you can do this on any small container close to the size of your stone so as not to use too much plaster and have to carve tons away afterwards. Then, once dry (at least overnight), you carve a duplicate of your stone. You will use this in your design as you would a ring plug, leaving enough clay around it so the clay will shrink, but not break during shrinkage since it will be stressed upon achieving the size of the plug. If you're planning on a bezel, then you can calculate the bezel (and space to be left for the stone) in your design by enlarging a photocopy of your stone by the percentage of shrinkage of the clay you are using, and make the bezel the enlarged size. You position your plug, centered, inside that bezel so the clay shrinks around it but stops at the size of your stone. Some extra tips for duplicating the stone are:
1) Drawing around it on a piece of paper then using that as your guide to cut the plaster. Once close to the stone shape, put them back to back until you make sure you've got it right (“back to back" only for a symmetric shaped stone, not good for an odd shaped stone where, if you put it back to back, you'll get it's mirror shape)
2) Measure the height with a caliper and check your plaster model.
Another possibility is making a print or a "well" with the actual stone directly onto the Metal Clay, then taking it out very carefully (ideally after dry, and having left a back hole to push the stone out) filling that with plaster. (For the back hole you can just put a little piece of paper so it won't drool out, which will burn during firing.) But you'll still have to make your design around it in a way that the stone will be held in place either with prongs, or with coils, or something since the hole that's left after firing should be the size of the stone, so it can pop out if you don't integrate some sort of bezel/prong/coil, etc. into your design. Don't forget to leave room to account for shrinkage here too, and also to make it deep enough.
~Angela B. Crispin
I like Tim's idea of mixing the plaster in little zip lock bags and sniping off one of the corners so you can squirt out the plaster like a pastry bag.
~Gordon Uyehara
High Temperature Investment is another option. Silicica-free investment available at: http://www.CoolTools.us. Make a mold of the stone using two-part silicone putty mix, Belicold, or any brand that makes a flexible mold. Flexible is important. I grease up the mold and pour investment into the mold. The same investment I use for making ring plugs. I set the plug in the bezel as a placeholder and fire.
~Carol Augustine
Plasticine modeling clay is infinitely re-usable and if you don't get a good impression of the stone on the first try, you can easily try again. You do need to make the model a tiny bit bigger than the real stone, so I use 2 layers of plastic wrap on small stones – wrap the stone in two layers of plastic wrap and twist around the top of the stone to get a form fitting spacer around the stone. Press into the modeling clay carefully to the level of the table to create an accurate model of a faceted stone.
~Mary Ellin D'Agostino
The mold you make in the clay/plasticine (Dick Blick modeling clay) isn't meant to be permanent. It is only used to make an impression of the stone/element you want to place in your clay during firing. Once the investment is hard, you peel the clay away and use it (the clay) again later to make another temporary mold for an investment mock up of a stone/element, etc.
~Laura Hastings
Polishing (Also See Finishing, Prefinishing, and Tumbling, White On the Surface of Metal Clay, Mirror Finish)
After firing and brass brushing your piece. For more aggressive polishing use 3mm rubber wheels made for silver and a flex shaft or dremel. Try using medium for "really" aggressive work, fine for a small imperfection, and very fine for the final high polish. The coarse grit for me is just too aggressive and even the medium can be very aggressive for the fine silver, so keep an eye out. The key is to keep the wheel moving or you will get grooves and wheel lines in the silver called, "drag" where the Metal actually looks like it has drag marks. Depending on how deep the imperfections are, a final tumble in a tumbler with steel shot or a polishing pad will give it a nice even look. This is my secret weapon for a mirror finish.
~Holly Gage, Metal Clay instructor
Reconstituting Metal Clay
If it is a dried-up lump of clay that hasn't been used, I’d just poke lots of holes in it, and put it in a plastic bag. Check on it in an hour, and keep adding water a bit at a time and smoosh the Metal Clay in the plastic. When you get to the point you can roll it out, roll it in between plastic several times super skinny until you have a nice smooth consistency.
When reconstituting recycled workbench bits or sanding bits remove any large debris or hair, and sift your clay through a medium-mesh sieve dedicated to craft use. Grind with a coffee grinder or with a mortar and pestle and sift again, but now through a small-mesh sieve. Spritz with water and mix with a pallet knife, add water a bit at a time until you have something you can roll, it shouldn't be too wet. Roll it in between plastic several times super skinny until you have a nice smooth consistency. Unless your debris removal was spotless, you probably ground up tiny bits of who knows what still in there, therefore I would use this batch for textured items, as a mirror finish probably isn't possible. I'd also consider wear and tear on the item as it might be a bit weaker. So considering thicker clay use, layered designs, and avoiding using it for bails and such.
~Holly Gage, Metal Clay instructor
Reshaping Dried Metal Clay
(See Warping Greenware Metal Clay)
Rings
Fine Silver isn't your best material for rings. I made one many moons ago and although it didn't break, the metal is soft and dings up so easily. 960, 950 and sterling are better candidates for rings.
Rollers and Rolling Clay Out
Uniform clay thickness. Pinzart.com – Pam East's slats: the slats are color coded to the thickness; measurements are in inches, mm, and cards.
~Jerri Duncan
Rollers. A piece of PVC pipe is an easy tool to get for rolling out slabs. But back in my pottery days, I was well aware that rolling pins are not all created equal. I had dozens of them for different jobs. Subtle bearing movement was critical for a clean roll. So too with PMC. I have always used the hard rubber printing brayers. They don't cost much, will last you a life time, and the handle makes all the difference in the world when it comes to the control over the thickness and evenness of the slab. (You are rolling with your wrist, not your hand.) The trick is to not try to roll flat all at once. Roll a few times lightly in one direction, never rolling off the edge, but leaving a fat lip. Pick the piece up, flip it upside down, and horizontally. Roll a few more times, LIGHTLY, flip again and turn vertically, repeat. By moving it around your work surface and flipping it, you never have to grease the clay, brayer, or your surface. I don't grease anything, but my hands, ever. The minute your brayer picks up any wet clay, stop, wash it off and dry. Once it has any bit of wet clay on it, it will keep picking up wet clay.
Though I have tried non-stick surfaces, which I did have to grease, I still keep coming back to good old freezer paper, shiny side up. When one part of the paper starts to show signs of getting wet or sticky, I move to a drier part, and let it dry out. Then once I have finished an especially delicate piece, instead of trying to get it off the surface, I just leave it alone. When it is dry it will just peel off the paper, but if I am in a hurry, I can cut the paper around the shape, so I never risk distortion, and set the paper on my coffee cup heater, or place on a pan and put in the oven. When some students have done especially fine syringe work, I just place it in the kiln on the paper, and let it burn up.
Though I don't know this for a fact, I suspect that over greasing a piece has a few disadvantages. As you cut out pieces, wad up the excess to reuse, it becomes difficult to know if the clay is still actually wet enough, or if it just seems wet because it is so greasy. (You will find out the difference soon enough if you then use that clay to try to roll a coil, it will look wet, but keep cracking.) If you are rolling out flat pieces you are just texturing, it isn't much of a problem. But if you are fabricating, I think eventually the grease is going to become a barrier to a good connection.
~Elizabeth R. Agte
Salvaging Metal Clay
You can reconstitute your Metal Clay by taking a tissue blade and chop your clay into small, evenly sized pieces. You can get a dedicated pepper grinder, chop the clay into small enough pieces to fit inside that, and grind. Get a small piece of Saran Wrap, place all your bits in the middle, add either water, or glycerine and water. I use PMC Tool and Supply's PMC Extender Liquid. If you use water, use an eye dropper, so you can add water slowly. Add Extender Liquid to just cover, wrap tightly, put inside a small container with a tightly closing lid, wait. Next day, knead the clay THROUGH THE SARAN WRAP, then add more water (if necessary). Continue as needed until clay is recovered and workable.
~Elaine Luther
Soldering
When soldering to Metal Clay many like to burnish the surface area to be soldered because of the porosity of the Metal Clay. After you have soldered something to the surface you can not put it in the kiln at high temperatures because the point of contact won't hold.
Sheet Metal and Wire Out of Clay
(Also see Glycerin)
I've been making my own wire and sheet from metal clay with good results by mixing glycerin into the clay. (Purchase at a drug store) Once the glycerin is mixed you can roll your clay to any desired size and thickness, or extrude the desired diameter and length from an extruder. When you roll your sheet you can also texture it on one or both sides. Let them air dry. Once they are dry, they stay flexible, allowing you to fold, weave, knot, even crochet. The advantage over spool wire is that it will never work harden. It's true that a lot of things that can be done with sheet metal and wire are hard to achieve this way, but the opposite is also true; you can achieve a lot of interesting designs that are impossible or very hard to achieve with sheet and wire.
The amount of glycerin depends on the amount of the clay. I roll a whole package very thin and just smear the whole surface with glycerin. Then I roll it into a cylinder, fold it in half, and start rolling under a sandwich bag over and over to work the glycerin in. It's very sticky at first, and you'll need to scrape it off the work surface. Keep working while oiling your hands and the surface to minimize sticking. Eventually the clay will regain its original consistency and just by looks you won't be able to tell it from regular clay.
Now you can prepare sheets and wires. The sheets can be textured and after drying can be cut with scissors or punched with hole punchers to create discs and other shapes. It can be stored for a long time, and if recycled, will be as flexible the second time. However, once fired the glycerin is gone! I will not be flexible anymore, so any work should be done prior to firing.
~Hadar Jacobson, http://www.artinsilver.com/
Texturing Metal Clay
Here are some ideas for making and using your own textures. Remember to have a barrier of lubrication between your Metal Clay and your texture.
Buttons
Glue antique, plastic, and metal buttons onto a bottle cork and use as a stamp. Neat buttons can be found at an antique store or fabric store.
Layered Carboard
You can get lots of dimension by cutting, gluing, and layering shapes of cardboard for a linear effect. Spray with a couple of layers of lacquer to give the texture plate longevity.
Linoleum
Linoleum plates come in different hardnesses for different effects, such as sharper images or softer images. Using dockyard cutters, or linoleum cutters, tool the surface to make your image or impression.
(Also see Photopolymer Plates)
Polymer Clay
Wet work polymer clay by pressing wire, ball stylus, dental tools, rubber shapers into the clay to create an impression. Then bake the polymer clay.
Also, bake a uniform sheet of polymer clay about 1/4" thick, and then carve into it with dockyard tools or lino cutting tools. Different brands of polymer will be softer or harder after baking and will give you different results. Premo and Super Sculpey® Original bake to a harder surface, where Fimo and Sculpey Bake and Bend will have a softer result.
Puffy Paint
Squirt puffy paint right out of the pointed nozzle and apply to cardboard and let dry
Rubber
Rubber plates and even erasers come in different hardnesses. Using cutters or lino cutters, tool the surface to make your image or impression
Scratch Foam
Is a white thin foam that accepts impressions with various tools, such as a ball stylus, ballpoint pen, and Exacto® knife. Experiment with different marks and depths. Back the foam with contact paper or packing tape allowing for deeper impressions.
String
Glue string to a substrate. the string makes a beautiful texture of linework.
Wood Cut
Using dockyard or other woodcutting tools cut into a woodblock. Seal with wood oil or even your badger balm.
~ Holly Gage, Metal Clay instructor
Torch Firing
Tumbling
Tumbling is performed in a small drum with a tight lid. As it rotates, the media inside bounces off the Fired Metal Clay work inside the drum. There are many different kinds of media available, but what we see most often is the stainless steel shot to make pieces shiny.
Tumblers don't necessarily give you a "mirror" finish, as you must do the proper sanding first and possibly rotary tool finishing. By definition, a mirror finish is when you see a reflection of yourself on the surface. By contrast, a tumbler makes whatever the surface is shiny, so for example, if you had an orange peel texture, it would make it shiner, but not flatten the surface completely. Tumbling is a great way to finish your pieces especially as a beginner seeking a shiny finish.
Other media such as plastic or coconut shell is available made for brush finishes, deburring, and mass finishing, etc.
Tumbling Glass
Tumbling Glass in your work requires nonabrasive media like the steel shot as it will not damage or scratch the glass.
Tumbling Soft Stones
Soft Stones should not go in the tumbler as they will get scratch and lose their shine. Stones low on the Mohns Scale which measures stone hardness such as Opal 5.5 or Malachite 4.0 are examples of poor candidates. I have saved a stone or two put in the tumbler by buffing it with ZAM® compound.
Work Hardening
I think there is value to work hardening or case hardening your Metal Clay jewelry in a tumbler. Work hardening is when you work a piece with tools such as hammers, burnishers, etc. to stiffen up the metal or harden it. A tumbler may not show a significant change as in when you pound it with a hammer with extreme force, but for such things as prongs, wire working, bezels or thinner items, it does add some strength as the steel shot bounces on the surface. It is something that you can test and feel. Work hardening happens at different rates of hardening with those other tools. The more force, the harder the metal becomes. I think if you run some tests you can experience it for yourself. I have.
~ Holly Gage, instructor
White "on" the surface of Metal Clay is called Kiln White
It really isn't "on' the Metal Clay, it is just unpolished silver. The profile of the silver shows small peaks, to the naked eye it "looks" white. The more you polish it the more the microscopic peaks flatten. Brass brushing is the start of the burnishing process, the more you polish the flatter the surface -- burnishing, tumbling, rotary polishing, and sanding all flatten the surface. The more you flatten the more the light can reflect off of it until you have a shiny or mirror finish.
~ Holly Gage, Metal Clay instructor
Warping Greenware Metal Clay or Reshaping Dried Metal Clay
Video: How do I Rehydrate, Reshape, or Fix Warped Greenware Metal Clay? With Holly Gage
Your secret weapon for fixing misshapen Metal Clay Greenware that has warped or you just a desire to change the shape without ruining the texture or integrity of the shape.