What can I do to promote even kiln firings?

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  • See the Sales FAQs for Frequently Asked Sales and Preorder Questions
  • The Knowledgebase is organized into a series of questions and answers having to do mostly with technical troubleshooting and understanding of kilns.
  • Although we write this for our own kilns many of these articles apply to other makes - although L&L takes no responsibility for that.
  • Many Knowledgebase articles have Actions, PDFs and Videos associated with them.
  • Actions are specific actions for you to take during the troubleshooting or repair process.
  • Each Action may also have Videos and PDFs associated with it and, in addition, specific Cautions.
What can I do to promote even kiln firings?

Control

  1. Our DynaTrol automatic control with Dynamic Zone Control is the state of the art way to do this.

Loading

  1. In addition, the way you load the kiln will help promote good uniform firings.
  2. You must keep enough space in the kiln to allow air to circulate.
  3. Make sure your shelves do not block elements.

Kiln Configuration

  1. If you are firing dense loads (such as tiles) you may want to consider one of our powered bottoms.

Venting

  1. A powered downdraft vent such as out Vent-Sure system will also help.

Maintenance

  1. Make sure all of your elements are working and are radiating heat evenly.

Additional Actions to Take

  1. On the next firing make up "cone packs" for each thermocouple.
  2. Once the cone packs are positioned on shelves and are visible through the peepholes, fire the kiln to the middle cone's number
  3. Start watching cones near the end of firing.
  4. Keep checking the control display to make sure it does not say CPLt.
  5. If the middle cones did not go down together then immediately note the differences in each thermocouple reading from the one thermocouple the same zone as the first cone that went down. Change the final set point of your program to reflect the difference.
  6. If the kiln is firing too hot then lower the final set point.
  7. If the kiln shut itself off before bending the cones properly, reprogram it and then restart it as quickly as possible. Record the temperature at which the kiln shut down. Stop and restart the kiln. Reprogram the same program to one cone number higher. Do these steps quickly. Watch the middle cones again and note at what temperature the cones properly bend. If they bent while you were programming then just offset the temperature by 5 or 6 degrees. Shut the kiln off once you note that temperature.
  1. Remove one of the Cotter pins from the Hinge Bar.
  2. Pull out the Hinge Bar.
  3. Unscrew the chains from the stainless steel case of the lid.
  4. Remove the Top Hinge Part from the old lid.
  5. Using the old top as a guide, install the Top Hinge Part onto the new lid.
  6. Reinstall the top.
  1. Unplug kiln.
  2. Remove or hinge open the control box.
  3. Remove the Thermocouple Lead Wire from the Thermocouple.
  4. Unscrew the Thermocouple from the kiln.
  5. Remove Thermocouple.
  6. Install a new Thermocouple and screw in place.
  7. Replace Thermocouple Lead Wire and tighten. Be sure to get red matched to the MINUS (Negative) sign and the Yellow matched to the PLUS (Positive) sign.

See this video:

  1. Carefully examine thermocouple tip. This is the exposed welded joint at the end of the thermocouple that is not covered up by the ceramic tube.
  2. To do this you will have to remove the thermocouple from its protection tube (if it is a kiln that has one of our protection tubes). You can do this with the kiln disconnected from power.
  3. Look for corrosion - especially if it severe. These thermocouple tips will oxidize and otherwise corrode over time. That is normal. There is some point, however, at which the corrosion affects the ability of the tip to work (thermocouples work by generating a small voltage at the tip caused by two different metals reacting to each other).
  4. Corroded thermocouple tip

  5. Make sure the two wires are securely joined. One of the things that can cause an intermittent problem is a bad weld. If the two wires touch each other (even if they are not welded) they may work temporarily. However, if the weld is not secure then the wires could separate when the kiln heats up and cause an intermittent failure.
  6. If the thermocouple tip looks healthy then test the control board.

  1. Make sure peepholes are plugged with peephole plugs.
  2. Make sure hole for vent is proper. Check Vent-Sure instructions for proper hole sizes.
  3. If you are using a different brand of vent make sure it is the appropriate size for the kiln. Check with the vent manufacturer and tell them how many cubic feet are in the kiln.
  4. If the lid or bottom is cracked check to see if it seems to leaking much heat at high temperatures. Patch or replace if extreme.
  1. If uneven firing occurs persistently, distribute your load weight more evenly throughout the kiln or to match the firing characteristics of the kiln.
  2. If elements typically fire hot at the top of the kiln put more weight in the top to absorb that heat, and vice versa.
  3. The bottom shelf should be at least 1/2" to 1" above the floor of the kiln.
  4. Badly distributed load weight can also affect the firing rate of the kiln and lead to Error 1.

TIP: The longer square posts can be laid down on their sides to get a perfect amount of space under the bottom shelf.