Metal Clay Kiln Firing Schedules

Below you will find the kiln firing times recommended by the manufacturer for each type of metal clay including PMC, Art Clay, BRONZclay™ and COPPRclay™.

Firing PMC Products

PMC Standard
1650°F / 990°C for two hours

PMC+
1650°F / 990°C for 10 minutes
1560°F / 850°C for 20 minutes
1470°F / 800°C for 30 minutes

PMC3
1290°F / 700°C for 10 minutes
1200°F / 650°C for 20 minutes
1110°F / 600°C for 45 minutes

PMC Gold Clay
1650°F / 900°C for 10 minutes
1560°F / 850°C for 20 minutes
1380°F / 750°C for 60 minutes
1290°F / 700°C for 90 minutes

CLICK HERE for a PMC Full Data Comparison Chart

Firing Art Clay Products

Art Clay Silver 650
1436°F / 780°C for 5 minutes
1382°F / 750°C for 10 minutes
1292°F / 700°C for 15 minutes
1202°F / 650°C for 30 minutes

Art Clay Silver 650 Slow Dry
1436°F / 780°C for 5 minutes
1382°F / 750°C for 10 minutes
1292°F / 700°C for 15 minutes
1202°F / 650°C for 30 minutes

Art Clay Silver Overlay Paste
1436°F / 780°C for 5 minutes
1382°F / 750°C for 10 minutes
1292°F / 700°C for 15 minutes
1202°F / 650°C for 30 minutes

Art Clay Silver Oil Paste
1562°F / 850°C for 10 minutes
1436°F / 780°C for 30 minutes

Art Clay Silver Paper
1562°F / 850°C for 20 minutes
1472°F / 800°C for 30 minutes

Art Clay Gold Clay
1814°F / 990°C for 60 minutes

Firing BRONZclay™ and COPPRclay™

Firing BRONZclay™ and COPPRclay™ is a two-step process that uses low heat to prepare the kiln's atmosphere, then high heat to sinter the alloy. BRONZclay™ and COPPRclay™ must be fired in a kiln. During firing, the non-toxic binder vaporizes, leaving a solid, pure bronze object.

Note: Make sure your piece is completely dry before firing; it's not a problem for the piece to dry for weeks before firing, but firing a piece while it's still damp can cause the moisture to expand, creating blisters.

To reduce oxidation, your piece(s) must be surrounded by activated carbon during firing. The coconut shell-based carbon produces a light patina color; the coal-based, acid-washed carbon produces a colorful, more intense range of patinas.

To Fire BRONZclay™ & COPPRclay™

  1. Spread 1" of activated carbon granules on the bottom of a stainless steel firing pan (#703-202).

  2. Place the piece on top of the layer; if firing two or more pieces, leave at least 1/2" between pieces; leave more if the pieces are larger. Note: Most kilns are cooler in the front near the door, so the front of your firing pan will be cooler than the back and sides. Compensate for this by placing pieces closer to the sides and back of the firing container. If you're using a top-loading kiln, there's no need to adjust.

  3. Pour more activated carbon granules on top of the piece until the container is full, making sure there is at least a 1/2" layer of granules on top of the piece. If you are firing several pieces in layers, make sure there is at least 1/2" of space between the vertical layers as well.

  4. Cover the firing pan with its lid and place it in the kiln on stilts to allow good heat circulation.

  5. The firing pan should be allowed to cool completely before removing it from the kiln; however, if you need to use your kiln again right away, you can move the pan to a heat-resistant surface (e.g.: a soldering pad or ceramic tile) and allow it to cool there.

  6. Once the firing pan and carbon have cooled, remove the BRONZclay™ pieces from the carbon bed and place them on a heat-resistant surface to finish cooling. You can re-use the activated carbon until you notice it starting to break down (broken grains and a sooty appearance). Note: If there are no stones embedded in the piece, it can be quenched in water.

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BRONZclay™ FIRING SCHEDULE:

For pieces up to and including 3mm (6 cards) thick:
Ramp at 500°F/hour to 1550°F and hold for 2 hours (total firing time, including ramp-time, will be between 4 and 5 hours).

For pieces thicker than 3mm (6 cards):
Ramp at 250°F/hour to 1550°F and hold for 3 hours (total firing time, including ramp-time, will be about 9 hours).

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COPPRclay™ FIRING SCHEDULE:

Regardless of thickness:
Ramp at full speed to 1700° (927°C) and hold for 3 hours (total firing time, including ramp-time, will be about 4 hours).

Firing for Enamels:
Read the article Firing COPPRclay™ with Enamels by Pam East

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Thickness Note: The firing schedule for thicker pieces will work fine for thin pieces should you have both thicknesses in your firing pan.

Kiln Note:
Most front-loading kilns are cooler in the front near the door, so the front of your firing pan will be cooler than the back and sides. To compensate for this, place pieces closer to the sides and back of the firing container. If you’re using a top-loading kiln, there’s no need to adjust. Avoid the front of the pan when using a front-loading kiln.

WARNING!!!
The firing pan will be extremely hot; do not touch! Allow the pan to cool completely before removing the lid. We recommend wearing heat-resistant gloves such as Rio 12" welding gloves (#350-051 and #350-050) while removing the firing pan.