KILNS & FURNACES
Electric in air to 1800°C • Research • Heat treatment
Controlled atmosphere • Melting • Gas, Natural/LPG to 2300°C
Tetlow Kiln Pty. Ltd. ABN: 26 166 832 300 54 Howleys Road, Notting Hill, 3168 Victoria Australia
T: +61 3 8545 8296 F: +61 3 9544 2723 E: info@tetlow.com.au www.tetlow.com.au
Give your pieces room to “breathe”. In order for the heat to properly fire your ceramic pieces, try
to leave at least 20 mm between pieces, and leave some room at the top of each level for the heat
to pass evenly throughout the kiln. If you find you are getting cold spots between pieces increase
the gap. Only air dried pieces should be loaded for bisque firing.
Glaze can bubble and splatter onto the kiln walls and shelves. For this reason, keep ware at least
30 mm away from element grooves and walls. Periodically check your kiln for glaze contamination.
Dig out glaze from kiln walls and the bottom with a putty knife, removing as little insulation as
possible. Again if you need advice, take a photo and email us for feedback.
SECTION 10 – GENERAL FIRING GUIDELINES
10.1 FIRST STAGE (BISQUE) FIRING:
In the beginning, go slow:
Even if you have air dried your ware for many days there will still be moisture trapped inside
the clay that needs to get out while firing.
If you go up in temperature too fast this trapped moisture turns to steam and can result in
ware ‘exploding’ in the kiln.
Once this moisture has escaped and the organic contents of the kiln have burnt off (around
300°C). It's not just the top temperature you must reach, it's the amount of heat and time the
ware receives. This means that the Ramp rate (rate of temperature rise) that occurs in the
last 100°C of rise is as important as the top temperature the ware must reach. This is why
clay often refers to a Cone number. These represent an amount of heat work.
For this reason, we suggest setting the last 100°C ramp at 60°C /hr. This represents the
middle of the chart for a Cone firing and gives the best results. We suggest you refer to an
Oroton Cone Chart which can be found on the internet.
To ensure the best results we would suggest adding a soak at the top of the cycle. This
allows the whole kiln to ‘catch up’ or even out to a uniform temperature and gives a little extra
time for the desired temperature to soak through the entire thickness of the ware. For bisque,
stoneware or ceramics we’d suggest 10 -15mins. (If you find you are getting cold spots in
your kiln you can extend this soak. Uneven packing can also be partially overcome by
extending this soak. Note: You need to try and see what works for your specific firing and
packing arrangements).
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