The rules for metal clay usage seem to be changing almost daily, as inventive jewelry makers experiment with techniques and firing schedules and spread the word of their discoveries. That can make it frustrating for newcomers to the field to figure out just what they’re supposed to do. The following series of charts is accurate at press time and will serve as a handy guide to the different types of clay on the market, how they can be used, and how they should be fired. However, we do encourage readers to check their specific clay manufacturer’s instructions when firing their pieces. —Charts compiled by Annie Pennington
firing and usage charts
FINE SILVER SYRINGE CLAY
PMC3 Syringe Art Clay Silver 650/1200 Low-Fire Syringe
Shrinkage 10–15% 8–10%
Firing Method Programmable kiln, hot pot, torch Programmable kiln, torch, gas stovetop
Firing Schedule 1650°F / 2 hrs1290°F / 10 min1200°F / 20 min1110°F / 30 minTorch: Varies by size of piece
Applied to porcelain or glass: 1472°F / no hold time needed1200°F / no hold time needed
Applied to Art Clay Silver Standard:1470°F / no hold time needed
Applied to Art Clay Silver 650/1200 (regular or slow dry):1472°F / no hold time needed1435°F / 5 min1380°F / 10 min1290°F / 15 min1200°F / 30 min
1560°F / 10 min1472°F / 30 min
Notes • Use to add texture and join unfired pieces.• Fill cracks and imperfections
• Use to add texture and join unfired pieces. • Fill cracks and imperfections
• For use on glass, ceramic, or other nonporous surfaces, including sterling silver• Dilute, or rehydrate with small amounts of distilled water until it reaches desired consistency
• Use to repair and attach fired pieces• Must use proper dilutant• Use to join silver bezel wire seams
Notes• All clay should be fired in an area with proper ventilation• Firing temperature should not exceed 1652°F due to possible melting• Use distilled water to resoften stiff or dry clay• Do not torch-fire designs made over combustible forms or with inclusions (gemstones, glass, etc.)
• High shrinkage allows you to make small pieces with great detail• Can be gently domed after firing, but is somewhat brittle. Work carefully to avoid cracking• Burnish before soldering
• Stronger than PMC Standard• Burnish before soldering
• Stronger than PMC+• Recommended for rings• Burnish before soldering
• 5x longer working time than Art Clay Silver Standard• Great for braiding, detail, molds, and projects requiring more working time
• Can use with glass, sterling, and settings
• Dries 4x slower than Art Clay Silver 650/1200 Low-Fire• Great for braiding, detail, molds, and proj-ects requiring more working time
FINE SILVER PAPER CLAY
PMC+ Paper Art Clay Silver Paper Type
Shrinkage 12% 8–10%
Firing Method Programmable kiln, torch Programmable kiln, torch (only if small sections have been applied to another surface)
Firing schedule 1650°F / 10 minTorch: Heat evenly, hold peach color 5–10 min
1562°F / 20 min 1472°F / 30 min
Notes• Can be used origami-style, paper punched and used as appliqué• Strips can be cut and woven
• Can be laminated to make it thicker• Use for making bezels• Cut with punches or scissors• No drying time needed before firing• Repair with ACS Oil Paste or lavender oil paste
• No drying needed before firing• Apply as little moisture as possible• Place in cold kiln and ramp to temperature• Ventilate well during firing.• Repair with ACS oil paste or lavender oil paste
* Nothing larger than 11/2 in. (38 mm) and weighing more than 25 g can be torch-fired.
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firing an
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sage charts
Most base metal clays need to be fired in a closed container in activated carbon.
SILVER ALLOYS
PMC Pro90% Silver10% Copper
PMC Sterling92.5 % Silver7.5% Copper
Shrinkage 15–20% 15–20%
Firing method Programmable kiln, in stainless steel pan, in coconut shell-based activated carbon
Programmable kiln with activated carbon
Firing Schedule 1400°F / 1 hr Stage 1: 1000°F / 30 min on kiln shelfStage 2: 1500°F / 45 min in activated carbon.Firing schedule changes based on number of pieces and thickness of pieces.
Notes • Ideal for rings, delicate designs, and compo-nents such as clasps, hinges, and prongs• Longer working time• Do not mix with other unfired clays• Do not fire above 1425°F• Ventilation required
• 3x stronger than fine silver metal clay• Good for carving, soldering, enam-eling, stone setting, keum-boo• Does not produce firescale during firing• Similar properties as cast silver
Fire on stainless-steel mesh in a pre-heated to 1500°F kiln / 30 min at 1500°ForFire on stainless-steel mesh in a pre-heated to 1100°F kiln / 10 min. CoolFire in activated carbon in preheated to 1500°F kiln / 60 minPickle to remove any oxidation
Notes• Strong after firing• Great for large-scale designs
• Powder, mix with distilled water• Not flexible after firing, will break if you try to form it
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GOLD METAL CLAY
PMC Gold (22k)(91.7% gold, 8.3% silver)
Art Clay Gold (22k)(91.7% gold, 8.3% silver)
Art Clay Gold Paste (22k)(91.7% gold, 8.3% silver)
Accent Gold for Silver (24k gold powder/non-toxic water-based medium)
Aura 22 Gold Paste(91.6% gold, 8.4% silver)
Shrinkage 14–19% 12–14%
15% 8–10% n/a n/a
Firing method Programmable kiln, torch
Programmable kiln Programmable kiln, gas stovetop Programmable kiln, torch, hot pot
1560°F / 30 minTorch: red glowHotpot: 30g fuelHotplate: until wood chars
Notes • Similar working properties as PMC3• Not recommended for rings• Can make into a paste• Melting point: 1832°F
• Melting point: 1931°F • Can make into a paste• Soften or rehydrate with water
• Stir well before using • Surface must be fresh from the kiln or cleaned prior to application• To fire: When applied to fine silver metal clay, place on a kiln shelf in a preheated kilnWhen applied to porcelain or ceramic, place in a cold kiln, heat to 1472°F then allow the kiln to cool to room temperature (no hold time)When applied to glass with COE 90, place in a cold kiln, heat to 1472°F and hold for 5 minutes; crash-cool to 1112°F, close kiln door, allow to cool to room temperature
• Powder must be mixed with included medium• Use on fired fine-silver clay, or sterling silver that has been depletion gilded• Apply multiple thin layers• When firing with a torch, apply metal clay paste to the area where the gold will be applied• Dry slowly• To fire: place onto a kiln shelf in a preheated kiln• Burnish after firing
• Surface must be fresh from the kiln• Best used on fine silver, can be applied to sterling silver that has been deple-tion gilded• After firing, burnish, brush and polish like any piece of gold
COPPER METAL CLAY
COPPRClay Art Clay CopperHadar’s Clay Traditional Copper
1560°F / 30 minor932°F / 10 min on shelf1560°F / 90 min in activated carbon
1472°F / 2 hrs when combined with Prometheus Bronze Clay)
Notes • Flexible when dry• Can be enameled (requires special firing schedule)
• Fire on open kiln shelf and pickle to remove scale • Not recommended: hotpot, beehive kiln
• Powder: mix with distilled water• Recommended for making flexible clay• Not flexible after firing, it will break if you try to form it
• Powder: mix with distilled water• Not flexible after firing, it will break if you try to form it
• Powder: mix with distilled water• Short lifespan after mixing• Will not fire if oxidized; dry in food dehydrator to prevent oxidation• See manufacturer’s instructions for firing with newspaper
• Dry completely before firing• Dry slowly• Can be made into a paste to connect parts• Pickle after firing• Available in lump and syringe
