Vertically line up the posts between shelves, especially when firing heavy loads.
If a kiln shelf breaks, you can sometimes salvage the pieces. Use a broken shelf section to load smaller ware around tall objects. You can also cut a cracked shelf along the crack to make half shelves.
A simple way to protect kiln shelves when test firing a glaze that might run: Place a small, flat slab of bisque clay under the ware. The slab should be about 1/8” thick, slightly larger than the ware, and kiln washed.
Apply several thin coats of kiln wash to the tops of shelves instead of one heavy coat.
Store shelves in a dry area. Moisture can cause shelves to crack or even to explode inside the kiln. A freshly kiln-washed shelf should be allowed to dry thoroughly, then fired slowly to allow any moisture in the shelf to evaporate.
Support full shelves with three posts instead of four.
Especially when firing heavy loads, the posts between shelves should line up vertically. This stabilizes the entire load and reduces stress on the shelves.
Six posts are often used to support two half shelves that are positioned side by side in a large kiln. However, you will save kiln space by supporting a set of half shelves with four posts instead of six. Position two posts in the center so that they support both half shelves. Place one additional post under the outer edge of each half shelf.
When possible, position posts toward the kiln walls and away from the center of the kiln. This places most of the weight of the kiln load close to the kiln stand and away from the kiln center, which has less support.
These questions are about last week’s Kiln Pointer on firing ceramic and glass decals:
Q. Should you kiln wash the tile holder supports?
A. If you are firing decals onto tiles, you do not need to kiln wash the tile holder. This is because it is unlikely that glaze will run at 1450 degrees F, the relatively low temperature used to fire decals. If you are firing higher, then it may be a good idea to kiln wash the tile holder.
Q. Where can I get those decals?
A. A local ceramic supply store is the best source of ceramic decals. Visit www.paragonweb.com and click on Where to Buy. Search by either state or zip code.
Or visit www.infospace.com and search for ceramic suppliers in your city. This is my favorite telephone directory website.
Q. I make dichroic glass jewelry. I ordered several decals from my glass supplier; however, no instructions were included. How does one fire decals onto dichroic glass?
A. Instructions for firing decals onto glass: The first time you fire a decal, use a test piece of glass. This is a general firing schedule that you may want to change to suit the types of projects you fire. The larger and thicker the glass, the slower the kiln should fire. Up to around 700 degrees F, vent the kiln. (Leave peephole plugs out and lid propped.) When the smoke disappears, close the lid. Glass jewelry can fire rapidly after the smoke disappears. Firing Schedule Segment 1: Rate 300 deg. F, Temp 800 deg. F
Segment 2: Rate 700 deg. F, Temp 1080 deg. F
Q. When I'm firing dichroic glass jewelry, should the vent hole on the top of the Paragon SC-2 always be closed or open? I've done it both ways but haven't seen any difference.
A. Venting is important when firing a core material such as cork clay inside a silver clay piece or when firing china paints, decals, fiber paper, and ceramics. Vent all firings that produce vapor or fumes. Venting is not always necessary with firing glass, though, especially small jewelry pieces.
One last pointer on summer vacations: If you buy glazed ceramics during your travels abroad, do not use it for food or drink unless you can verify that the glazes are food-safe.
I hope you are enjoying your summer. This year it is especially hot here in Mesquite. Yesterday the temperature was 105 deg. F.
With best wishes,
Arnold Howard Paragon Industries, L.P. - Better Designed Kilns 2011 South Town East Blvd. Mesquite, TX 75149-1122 Voice: 972-288-7557 & 800-876-4328 / Fax: 972-222-0646 email@example.com / www.paragonweb.com
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