Introducing the newest additions to the family, Olympic's Raku and Torchbearer Gas Fired Kilns. If you’re looking for a way to add a completely different dimension to your ceramic art then you’ll want to investigate gas kiln firing.
What are Gas Fired Kilns?
Well, Gas Fired Kilns are heated by the combustion of propane or natural gas. With gas firing, you can control the internal firing atmosphere of the work environment, which directly affects the outcome of your glazes and clay bodies. Gas kilns have the advantage of firing to very high temps, often exceeding electric kiln temperatures of 2350°F. In comparison to wood fired or non-electric methods, another advantage of gas kilns is that they do not require stoking to maintain their temperature.
Having both the ability to control the temperature and firing atmosphere of your work environment is the chief motivating factor for most artists in choosing a gas kiln. Creating an atmosphere of deprived/starved oxygen where carbon monoxide is produced which is known as reduction. The reduction cycle is responsible for a wonderful and unique palette of colors that occur when oxygen-deprived molecules seek the chemically bound oxygen from minerals that are in clay and glazes. Various glaze colors can be achieved in a reduction firing. The Copper reds are very hard to achieve with other firing methods, but in reduction a wide range of reds can be achieved, and these are some of the most dramatic. Rarely can a reduction atmosphere be achieved in an electric kiln safely.
Gas Fired Raku Kilns
Olympic Raku gas kilns are specially designed for raku work by retaining heat in the firing chamber when elevated by the turn of a hand winch, allowing easy access, while trapping the heat in the kiln and away from the operator. Today potters can create the ancient Japanese technique, raku and its unique beauty, metallic luster, and colors with an Olympic Raku kiln. The raku process involves reducing (starving the oxygen) the glazed raku pottery in combustible materials such as leaves, sawdust, newspaper, etc. When the pieces are ready to take out of the kiln, they are placed in galvanized trash containers with combustible materials and covered. Once the pieces are cooled down, they are removed from the containers, washed, and reveal the rich warm effects of raku. (Sounds fun, doesn't it?)
Gas Fired Torchbearer Kilns
Torchbearer kilns, with their portability, offer many advantages such as low initial cost, convenient movement for demonstration ﬁrings, and for use in situations where space does not permit the installation of large permanent kilns. Torchbearer models fire using either natural gas or propane and may be easily adjusted for oxidation and reduction ﬁrings. The multiple burner conﬁguration gives the Torchbearer even heating characteristics, fast controllable ﬁring times, and economical operation.
How do you operate an UpDraft Gas Kiln?
Once the kiln is hooked to a gas source, each burner may be ignited with a fire stick and the primary air-adjusted for each of the air mixers or burners. Before attempting to adjust burners, loosen the locking screw. The locking screw is not re-tightened unless the kiln is moved.
Air adjustment is accomplished by revolving the adjustment shutter plate up or down below the air mixer. The recommended starting point for natural gas is 1/4” and for propane 3/8” – 1/2”.
The air adjusting plate is locked between the burner orifice and the burner. To move this plate the burner must be loosened slightly from the brass orifice which threads into the center of the burner. Air adjustment is very important and should be accomplished with care. After loosening the locking screw and the burner from the orifice, rotate each plate to ensure it will move freely. Next position each air adjustment plate so the air inlets are 50% open. The kiln may be ignited while fine air adjustments are being made.
A properly adjusted kiln will have all flames uniform in appearance with the transition from the candle flame to intense flame occurring at the same time for each burner as the gas valve is opened. The kiln operates most efficiently when the intense flame has a bright blue color. Propane gas will not generate as intense blue color flame as natural gas. If the flame tends to blow out when the gas valve is opened the air inlet should be closed slightly. The air adjustment of the burners is not be changed once the optimum settings are obtained; however, reduction firing in the kiln may be accomplished by closing the air inlets. The easiest and most reproducible reduction is obtained by placing a damper (kiln brick, kiln shelf ) over the vent hole in the lid.
If you plan to use natural gas with your kiln, a large burner is necessary when used on natural gas pressure, you will need 6-8 inches of the water column. If you order your kiln for household natural gas use, it will be equipped this way. The natural gas pipeline that connects to the kiln needs to have a 3/4" inside diameter. If you plan to use propane gas, your tank must have a low-pressure regulator like those on a camper trailer. If an adjustable regulator is being used, about 1/2 pound pressure is necessary. The gas pipeline needs to be a hard line with a ¾” inside diameter. The line should run 20 – 40 ft. long from the propane tank. The larger the tank the better; however, a five (5) gallon tank is the minimum size for the 1827G or 18 Raku, and a 15-gallon tank is the minimum size for the 2327G/23 Raku and 2827G/28 Raku kilns. Due to gas flow, the propane tank may tend to freeze solid. If ice is observed forming on the outside of the tank, water can be run over it to help keep it melted. The tank can also be lowered into a large bucket of warm water. When portable tanks are used for rakuing, keep gas tanks at a safe distance from the kiln.
Gas Kilns Options - We think this safety add-on is a must!
The ignition system is used to:
- Light the multiple burner system from one point
- Maintain the flame on each burner
- Re-ignite any burner that may extinguish
The thermocouple safety shut-off will stop the gas flow if the flame is lost entirely. Learn more about how to operate the ignition system and its thermocouple here.
High Limit Controller - Make it Digital!
The High Limit Controller provides a digital reading of the temperature during the firing and shuts the kiln off at a preset temperature. The controller is wall-mounted and requires a 120-volt outlet. The controller may be retrofitted after the purchase of an Olympic Torchbearer or Raku gas kiln.
Gas Kilns offer many more options to customize and make your own! Check out our selection of Gas Fired Kilns here.
To get more info on Gas Fired Kilns, visit our Gas Kilns 101 page to learn more. There is so much more information on gas kilns on our site. So, if you want to go on the deep dive it's worth the trip!
Enter a new ceramic art dimension with these Olympic Gas Fired Kilns. We are so excited to see the results of your work!