Kiln Q&A

Learning from others is at the heart of the kiln community. So, I thought everyone would enjoy some Q&A as we just love to share knowledge and information! When using or buying a kiln... this extra insight not only saves you time but, often money, too!
Can a small test kiln accurately duplicate the firing of my larger pottery kiln?

A digital controller on a test kiln can duplicate the firing of a large kiln. Find a test kiln that has a simple 3-key controller. It won't have all the features of the more expensive 12-key controller, nevertheless, it can slow the cooling to whatever speed you want. Keep in mind that most 120-volt kilns are rated to 2000 F so, make sure you use one that is rated to 2300 F. Examples for great small test kilns are the Paragon Caldera Digital and the Olympic HB86E.

I need a small kiln that can be moved often. What do you recommend?
Since you are going to move the kiln frequently, we would suggest a fiber kiln. They are lighter than firebrick kilns. However, you can move a small, tabletop firebrick kiln without damaging it, you just need to be extra careful. Whether you get a fiber or firebrick kiln, its a good idea to save the carton and foam packing from the original shipment. The packing is designed to protect the kiln. Also, be sure to place a sheet of foam packing material between the kiln body and door or lid whenever you move a kiln for extra security.

Is there a reason to buy a ceramic shelf instead of a fiber shelf? 
A ceramic shelf is recommended for activities like pattern bars, pot melts, high fires, or any there techniques that requires temp to be held at 1450F or above. A fiber shelf will be marred by these activities and won't stay smooth as the glass moves.

Can a kiln be safely operated on a wooden work table? 
Yes, but it's not ideal! You will need a liner to buffer the heat. We recommend a concrete board, i.e. hardy-backer or Duraboard, or at the minimum, a double layer of ceramic tiles. It is easy to find at your local hardware store, and it's fireproof so it will protect the table and the area. Metal is always the preferred surface for a kiln table or cart.

I'm curious how hot a fiber kiln gets on the outside vs. a conventional kiln?
A fiber kiln reflects heat internally and a brick kiln absorbs the heat, so a fiber kiln will not be as hot on the outside. With that said, at a full fuse (1480F) the kiln might be 200-300F degrees on the outside.

Is it worth the extra cost for a solid state or mercury relay on a new kiln?
Glass fusing kilns are much harder on relays than ceramic kilns because of the very long glass annealing times that are typical with glass. (The glass is cooled slowly during annealing.) The same holds true for heat treating, crystalline glazes, bead annealing or any kiln that is holding temp for a long period. With that in mind, we think the optional mercury relay or solid state relays are well worth the money. They cut down on maintenance and help you elements last longer too!

How much heat is lost through a kiln’s bead doors when mandrels are inside?
With bead mandrels extending out past the bead door of a kiln, there is some loss of heat, but it is minor. In our opinion, not enough to make a difference. The kiln's digital controller and thermocouple will sense any differential and accommodate for this by firing the elements when needed to make up for any heat loss.

Do I need a top load or a front load glass kiln?
Top load kilns offer the most size for the cost. They can fire most glass projects but they are not good for projects that require manipulating the glass during the firing as the artist is subjected directly to the heat when the lid is opened nor are they recommended for bead annealing. Front load kilns are better for bead annealing and manipulating glass during the firing. They are also easier to load with large glass projects on the kilns shelves.

What type of kiln is best for copper enameling?
Copper enameling is best done in a front-loading kiln. This is because the copper pieces are removed while red-hot. When you open the door of a front-loading kiln and remove the piece with an enameling fork, you are comfortably out of the way of the rising heat. Removing an enameled piece from a top-loading kiln is more awkward and can be dangerous. Before opening the kiln to remove the piece, always turn off the power to the elements, which may mean turning the kiln off if your kiln did not come with a power interrupt switch. To enamel another piece, you can turn the power back on after you have closed the kiln door. To check out an example take a look at the Paragon SC2.

How is depth measured in a kiln?
The interior depth is always front-to-back for a kiln with a door and top-to-bottom for a kiln with a lid. For outside kiln dimensions, depth is the distance from the front to the back.

For glass, do I need elements in the top and sides or only the top?
Glass does not like temperature variation. Though top elements offer even heating across a flat piece of glass, top and sidewall elements are recommended for firing tall or deep pieces with molds. Side elements offer more even heating of the sides of drape molds or deep castings. Basically, the deeper you want to slump, the more side elements become necessary.

How do I get a wide ceramic kiln through a 32” doorway?
Many top-loading ceramic kilns are sectional. You can disassemble them and carry the sections through narrow doorways or downstairs. It can take some time for a beginner to disassemble and reassemble a sectional kiln. If the kiln is front-loading, you can temporarily remove the door handle and the back element cover. If necessary, you could also remove the door itself. Please have a kiln technician remove and reinstall the door for you if you do not feel comfortable with the project.

An example of a kiln that is structured in sections is the Olympic 2827HE.

Have more questions? Call us... as always, we are happy to help!

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