If your hobbies include making ceramic, glass, or pottery wares, then you probably have some experience using a kiln. While the earliest kilns date back to about 6,000 B.C.E., it is estimated that the highest firing temperature they could reach was somewhere around 1,650 degrees Fahrenheit or less. Today’s kilns can do a bit better, reaching temperatures between 1,800 to 2,400 degrees Fahrenheit. These high temperatures mean the kiln requires special care to do its job.
Why Does the Inside of a Kiln Matter?
Items are not placed within a kiln when it is already heated. Instead, the item’s temperature rises as the temperature inside the kiln does. The increase and decrease in temperature for firing has a great impact on the finished product. This is why experts recommend that no items are placed to close to the kiln’s walls where hot spots can develop, which is a gap of at least one and a half inches from the kiln elements.
How Are Most Modern Kilns Heated?
Kiln elements are what the heating wires and coils inside the apparatus are called. They are typically made of Kanthal, a Swedish metal that heats to temperatures over 2,400 degrees Fahrenheit. However, kiln elements can wear out over time. A kiln element will usually last for about 100 firings, making these components necessary to replace in high-use studios.
Why Is a Ceramic Coating Used Inside the Kiln?
A common product used in kiln maintenance is ITC ceramic coatings. Ceramic is a good choice for protective insulation because of its capabilities. The average ceramic can withstand temperatures of about 2,000 degrees Fahrenheit. An ITC ceramic coating can withstand about 5,000 degrees Fahrenheit.
As a kiln heats, the ITC ceramic coating does the much-needed job of protecting the interior components of the kiln by dispersing and radiating the heat generated by the kiln elements. A good coating can also help reduce excessive heat loss, which can effect the finished product forming in the kiln.
The Importance of Using the Correct Type of ITC Coating.
While ITC ceramic coatings are often used for protecting kilns, there are different types. The four basic types of ITC ceramic coatings are:
100HT, which is applied to the interior of the kiln for basic protection.
213, which is applied to metals to protect against oxidation, and is used in the making of molten glass and glazes.
296A, which is used as a top coating over ITC 100 to enhance kiln performance in delicate work such as jewelry and porcelain.
200 EZ, which is used as a repair job for chipped, cracked, or broken burner blocks.
Kilns have been used for a long time. The ancient model has seen some upgrades of course to allow ever finer pieces to be made. However, it is important to note that kilns do require some protective measures to create the best pieces of work. Using the proper ceramic insulation coating makes this easy, but it is important to choose the correct type.