| From the pages of Pottery Making Illustrated
Tools of the Trade: Rejuvenate Your Kiln by Arnold Howard
Your kiln will last a long time even if it has broken bricks and a rusted steel case. What may look like the worst or most serious damage is often just cosmetic and doesn’t affect your firing results. Here are a few simple things you can do to make your kiln last longer, even if it’s cosmetically challenged.
Dust can cause components in the switch box to overheat because dust acts as an insulator.
• Unplug the kiln, open the switch box (see your instruction manual). Wearing a dust mask, blow out the dust with canned air, which is available from computer stores or other retailers. Hold the air nozzle six inches away from the parts you are spraying.
• You can also use a vacuum cleaner and a dry paintbrush to clean the switch box, but only on switch-operated kilns. On digital kilns, a vacuum cleaner creates a static charge that could damage the electronic controller.
When you bend the wires inside the box, do you hear or feel the insulation cracking?
• When insulation cracks off the wires, it’s likely that strands of wire are breaking too, which can raise the resistance and cause them to overheat. Replace damaged wires. NEVER use electrical tape inside a kiln switch box.
Check the wire terminals for tightness.
• Squeeze loose push-on terminals with pliers to tighten.
• Replace terminals that are loose due to heat damage.
Reinstall the switch box.
• Arrange the wires so that when the switch box is placed against the kiln, none of them touch an element connector or the kiln case. These get hot enough to eventually burn wire insulation, which could cause a short circuit.
The easiest kiln maintenance is regular vacuuming.
• Use the soft brush nozzle and be sure to vacuum the element grooves, the inner surface of the kiln lid or roof, and the underside of kiln shelves. Remove any bisque ware shards that get lodged in the element grooves; the debris can cause element failure.
• Vacuum the kiln often if you use silica sand on the shelves to support ware. Sand can ruin the elements if it filters down into an element groove.
• As you vacuum the kiln, examine the walls for glass or glaze particles embedded in the firebricks. Dig them out carefully with a screwdriver.
Coat the Brick Floor
Kiln wash the firebrick floor.
• If the kiln wash cracks or flakes off, reapply it only to the bare spots. Don’t remove the kiln wash from the firebrick floor.
• Avoid splashing kiln wash onto the kiln walls, especially if you have sidewall elements; it will destroy the elements. Leave the floor uncoated if your kiln has an element in the floor.
| Fire Dry Ware and Shelves |
Both greenware and shelves should be bone-dry and warm to the touch before firing. If you fire moist ware, don’t heat past 200°F until all signs of vapor have disappeared. Moisture turning to steam quickly can damage the firebricks or your work.
Extend the Life of Top Wall Bricks
The top rim of sidewall firebricks is the area of a top-loading kiln most prone to damage.
• Place as little weight as possible on the kiln during loading and unloading.
• Reduce brick damage by cutting a three to four inch wide piece of plywood so that its curve follows the contour of the kiln. Place this plywood over the edge of the kiln when the lid is open. When loading and unloading, lean against the plywood instead of directly on the brick rim.
The extra time and care you give when loading and unloading can add years of life to your kiln.
• Keep the lid closed when you’re not using the kiln. This keeps dust out and prevents the lid from accidentally dropping while you are away. Don’t store anything inside or on top of the kiln.
• During loading and unloading, don’t touch the sidewalls of the kiln with anything. Take care not to bump shelves into the firebricks as they can cause serious breaks in the soft bricks. •
Arnold Howard writes kiln instruction manuals and catalogs for Paragon Industries, L.P. in Mesquite, Texas. For comments and more information, go to www.paragonweb.com.
|
Subscribe Today
to get great content like this delivered right to your door!
|
|