Gas Kiln Firing and Kiln Logging Information

Updated 1/20/22 - this material is subject to change

Fill in  Kiln Log Information:

  • Date, Weather, Cones, Name, End Temp

  • Look at past logs for a schedule of increases

  • Call Deb 206-673-6454 for any challenges or questions

Lighting the kiln

  • Make sure you can see your peeps and have written down cones before lighting the kiln

  • Make sure all the individual burner gas levers are off on before lighting

  • Start with two burners (kitty corner) on for a bisque/ all 4 for a glaze firing

  • Use the torch to light the kiln with the kiln door and damper open

Timing

  • Consistently log the kiln at least every hour or more 

  • Checking the kiln needs to happen regularly to have an accurate “Rate of increase”. 

  • Check past logs to determine how fast to turn up the gas

Gas

  • Notice the tick marks on the gas gauges.  Track gas levels on the log

  • Gas gauges are not all the same.

  • The numbers on the gauge equal pounds of pressure

  • Usually, we turn up the gas in ½ pound increments. Sometimes in full-pound increments

Temperature

  • Write the Fahrenheit temperature of the kiln

  • Calculate this from the Multimeter number using the temp chart

  • Use this to calculate the rate of increase

  • The Multimeter/pyrometer shows if the temp is going up or down.  It is not necessarily an accurate temp reading.  Use the cones for the most accurate temp readings.  

  • Compare the color of the kiln and cones to the multimeter to determine accuracy.

Rate of Increase

  • We want the kiln to increase around 200º an hour or faster after red heat

  • Sometimes more gas slows the firing down!

  • Take the most recent kiln check temperature and subtract the last reading temperature. If you are checking the kiln every hour this is your number.  If you are checking the kiln every ½ hour, divide this number by 2.

Oxy

  • For class firings, we want an oxidation or neutral atmosphere in the kiln

  • Check with the Multimeter with dial on 3 (showing three decimal places)

  • Switch the dial to 2 (showing two decimal places) if the number is jumping from low to high. Make adjustments to ensure the high number does not exceed the Highest Oxy #.

Temp with Oxygen Numbers. We aim for a low to medium Oxygen Level in a neutral firing.

1290ºF Low .064, Medium .098, High .112

1470ºF Low .070, Medium .108, High .124

1650ºF Low .077, Medium .118, High .135

1830ºF Low .083, Medium .128, High .147

2010ºF Low .090, Medium .138, High .179

2190ºF+ Low .097, Medium .148, High .192

Damper

  • The damper controls the pull of the chimney on the air in the kiln (draft)

  • Use the damper to adjust the air the kiln has access to

  • The kiln is VERY sensitive to changes in the damper

  • The kiln post over the damper controls the secondary air. 

Cones/ Notes

  • Write cone drops, color of the kiln here, evenness of the kiln, 

Shutting off the Kiln

  • When cone six is getting soft, shut off kiln (before it touches the shelf)

  • Shut off Main gas first

  • Shut of each individual burner gas levers next

  • Push in damper

  • Make sure peeps are in

  • Put away Multimeter and kiln log in office

Tips for Firing

  • Use your senses and be attentive to the kiln

  • Check the kiln regularly to help create a rhythm and consistency in your notes

  • Set an alarm and always go check it at the appropriate time

  • If you have a questions, call/ text Deb - 206-673-6454

  • We want the kiln to stay in a neutral atmosphere. If in doubt, use less gas or give the kiln more air.

  • The kiln is very responsive = small changes make a big difference

  • The damper helps control how much air the kiln has.  Pushing it in gives it less air.  Pulling it out gives it more air.

  • If a kiln does not have enough air, it will start reducing.
    This will equal higher numbers on the multimeter or a flame coming out the peeps when you check cones.