Fired Arts & Crafts
Kiln Maintenance
Monday, 08 November 2010 15:30

The worst time to find out something is wrong with your kiln is when you are trying to fire a load. Preventative maintenance is a much better way to go. Taking the time and completing these simple steps on a regular basis may save you time and money in the long term.


  • Check the interior of your kiln for anything that looks out of place.
  • Remove any loose pieces of firebrick from the walls or lid. Loose pieces can fall on your ware during firing and stick to glazes. Replace brick when elements start bulging out or sagging. Element staples will work to hold elements for short periods.
  • Remove any glaze spots from walls, shelves, posts, or bottom of kiln. If this is not done, glaze can melt and spread into element grooves causing shorter element life.
  • Double check shelves for any cracks. Do not use a shelf if cracked. It can split in firing resulting in severe damage to the kiln and your ware.
  • Cover bare spots on shelves with fresh kiln wash (most important in glaze firings).
  • Check for loose or bulging elements. Use element staples to hold them in place or replace firebrick.
  • If your kiln is equipped with a kiln sitter, clean any residue or kiln wash off the sensing rod and cone supports and coat with fresh kiln wash. This will prevent the cones from sticking. If any materials cannot be removed from the cone supports, they must be replaced.
  • If your kiln is equipped with a thermocouple, gently wiggle it to be sure it is not cracked.
  • Make sure nothing flammable is coming into contact with the kiln and the cord is not touching the sides of the kiln.
  • Be sure nothing is in front of the kiln preventing the weight from dropping on a kiln sitter (if equipped).


  • Vacuum the interior of your kiln.
  • Make sure your kiln is level. Kilns that are not level or rock can have shelves tip inside as a result.
  • Remove and inspect your cone supports if the kiln is equipped with a kiln sitter. If they are bent at all, replace them.
  • Check your porcelain tube assembly on the kiln sitter (if equipped). If you detect any cracks or chips, replace it.


  • Tighten kiln lid and jacket if needed. Most kilns have screws on one side.
  • If your kiln is equipped with a kiln sitter, use the firing gauge to check accuracy of sitter. Purchase a new firing gauge if you have misplaced it.
  • Check the receptacle and plug for any corrosion or melted areas. If the plug is not making good contact inside the receptacle, arching can occur and will melt the plug. If you detect any problems, immediately replace the plug and receptacle. If your kiln is sectional or has a ring, check the connections between sections.


  • Remove the control panel (after disconnecting power) and check over all wiring and connections. Replace or repair any loose or brittle wires or connections. Remove dust or debris by blowing with compressed air or using a soft brush attachment on a vacuum to suck it away.

Some things on your kiln will need to be replaced depending on how frequently you fire:

  • Sensing rod on kiln sitters - always have a new rod on hand. Hold it up periodically to the one in your kiln. If you notice the diameter of the one in your kiln is wearing down, replace it.
  • Thermocouple(s) on digital kilns - always have a new thermocouple on hand. All it takes is a slip of a shelf while loading or unloading the kiln to break this important part. Your kiln will not work without it. This part can also wear out without notice. If you notice your kiln is over or under firing consistently, it may be time to replace the thermocouple.
  • Elements - Always have extra elements on hand. Some kilns have more than one kind of element, so be sure you have each. Most elements will last for years. The most common cause of element failure is foreign objects melting in the element groove. Elements will eventually wear down and you will notice it taking longer and longer to complete a firing. At that point, you may want to consider replacing them.