Electric vs gas kiln firing

An electric kiln fires in oxidation, and a fuel-burning gas kiln can fire in oxidation or reduction. That difference drives everything else. Electric schedules are written as ramps, holds, and cooling segments a controller runs on its own, while a gas firing is steered by damper and burner adjustments read from the flame and the cones.

Veroffentlicht am 22. Juli 2026 · Quelle: Ceramic Arts Network, Tips and Tools: Firing Schedules

The two kilns share the same chemistry. Clay still gives up water, then organics, then crosses quartz inversion, then vitrifies, and the same cones measure the same heat-work in both. What changes is who is driving, and what the atmosphere inside is doing while the temperature climbs.

If you are moving between the two, most of your schedule knowledge carries over. What does not carry over is the assumption that a program can be typed in and left alone. A gas firing is a shift, not a setting, and the schedule you write for it is a plan for what a person will do rather than a list of instructions the kiln will execute.

What is the difference between electric and gas firing?

Atmosphere and control. An electric kiln heats with resistance elements and no combustion, so the interior stays oxidizing unless something is deliberately introduced. A gas kiln burns fuel, and by restricting the air it gets you can starve the atmosphere of oxygen, which then pulls oxygen out of metal oxides in the clay and glaze instead.

A reduced atmosphere is why gas kilns are the traditional home of celadon, shino, copper red, and iron saturate surfaces. The same glaze fired in oxidation and in reduction can come out two different colors. Reduction also changes the clay body, since iron in a stoneware reduces and gives the toasty, speckled surface that oxidation does not.

Electric kilns pay that back in repeatability. A controller runs the same ramps and holds every time, unattended, and results drift only as elements age. A gas firing depends on a person watching the flame, the damper, and the cones, and two firings of the same kiln by two people will differ.

The practical differences pile up around that. An electric kiln plugs in, needs a dedicated circuit and a vent, and can be installed in a garage or a spare room. A gas kiln needs a fuel supply, a flue, combustion air, and usually an outdoor or purpose-built space, along with an install that satisfies local gas and fire code. Running costs move the same way: elements are a consumable in one, fuel and burner maintenance in the other.

Can an electric kiln fire in reduction?

Not safely as a routine practice. Reduction in an electric kiln means introducing combustible material or gas into a chamber whose elements depend on an oxide layer for their life, and it wears them out quickly. It also produces carbon monoxide inside a kiln that was never designed to vent combustion products.

What electric kilns can do is imitate some reduction effects through glaze chemistry and cooling. Many potters who came from high-fire reduction have rebuilt their palette for cone 6 oxidation, using iron, rutile, and a controlled cool to get depth and variegation. That is a recipe and cooling project rather than an atmosphere project.

The safe rule: unless your kiln maker specifically supports it and your ventilation is built for combustion products, treat an electric kiln as an oxidation kiln and design around it. The manufacturer manual is the authority here, not a forum post.

When do you start reduction relative to the cone?

Body reduction starts low, glaze reduction runs high. A commonly published sequence begins the firing in oxidation, starts reduction when cone 012 bends near 1582 F, holds a climbing reduction to about cone 04 near 1945 F, then opens the damper again and finishes to the top cone.

The reasoning follows the clay. Carbon in the body has to burn out in oxidation before the surface begins to seal, so heavy reduction too early causes black coring. Ceramic Arts Network puts the oxidation window at roughly 573 to 1291 F (300 to 700 C), which sits below the usual body-reduction start point for exactly that reason.

One published schedule from Odyssey Clayworks fires with the damper open about two and a half inches until cone 012, reduces heavily for around five minutes, then eases the damper out to hold a climbing reduction of roughly 60 to 80 F per hour up to cone 04, a stretch of about four hours. The damper is then opened and the kiln climbs to peak. Small moves matter: an eighth of an inch on the damper is enough to change the flame at the peep.

Numbers like those belong to that kiln. Chimney height, burner type, kiln volume, and the weather on the day all shift them. What transfers is the shape of the firing: oxidize through burnout, reduce through the middle, decide at the top.

What does a gas firing schedule look like in practice?

It looks like a sequence of decisions rather than a list of segments. The written plan sets targets and a rough pace, and a person adjusts burners and damper to hit them while reading the flame at the peeps and the cones through the spy hole. The shape below is typical of a cone 10 reduction firing.

1. Preheat and candle. Low burners overnight or for several hours on damp or thick work, with the damper open so moisture leaves.
2. Oxidizing climb. Full air through carbon burnout, roughly 573 to 1291 F, so the body has oxygen while organics leave.
3. Body reduction. Begin when the low guide cone bends, commonly cone 012 near 1582 F, and hold a climbing reduction rather than a stalled one.
4. Reoxidize or lighten. Around cone 04, near 1945 F, many potters open up before settling into the reduction they want for the glazes.
5. Glaze reduction and the climb to peak. Watch the guide cone, then the target cone. A soak at the top evens out the kiln.
6. Shut down. Close the damper and the burner ports to slow the cool, since a gas kiln loses heat up the flue faster than an electric kiln loses it through the wall.

Compare that with an electric program: five or six segments typed in once and reused. The gas version rewards attention and gives surfaces an electric kiln cannot make. The electric version rewards record keeping and gives the same result on a Tuesday as it did on a Friday. Neither is better in the abstract, and plenty of studios run both.

What can a controller do in each kiln?

In an electric kiln, everything except judge the cone. The controller runs ramps, holds, and cooling segments and shuts off on a temperature or a cone-fire program. In a gas kiln a controller can drive the burners toward a temperature curve, but it cannot see or set atmosphere, which is the part that makes a reduction firing a reduction firing.

• Electric, a controller can do: multi-segment ramps, a candling hold, a hold at peak, a drop-and-hold, programmed cooling, and repeatable unattended firing within the limits your manual allows.
• Electric, a controller cannot do: measure heat-work. A cone-fire program uses a thermocouple and a factory table, not a cone in your load.
• Gas, a controller can do: hold a target climb rate on the burners, log temperature, and give you a consistent baseline to reduce against.
• Gas, a controller cannot do: judge the flame, set the damper, or tell you whether the kiln is actually in reduction. An oxygen probe measures it; a person still decides.
• Both: a thermocouple ages and drifts, and it reads the air near it rather than the ware. Witness cones settle what really happened.

What carries over between the two?

The physics and most of the schedule shape. Candling, organic burnout, easing across quartz inversion, slowing the final approach to the cone, and controlled cooling all matter in both kilns. Cones read the same in both. The bisque is close to identical, which is why many gas studios bisque in an electric kiln.

Firing pace carries over too. A slow approach over the last stretch lets heat-work catch up at a lower peak temperature in either kiln, because a cone responds to time as well as degrees. That is why Orton publishes temperature equivalents against a heating rate for the last 180 F of the firing, and why the same cone number covers a spread of more than 100 F.

Cooling carries over with one difference. A gas kiln loses heat up the flue, so it usually cools faster than a comparable electric kiln unless you close the damper and the burner ports. Slow cooling for glaze effects is achievable in both, with different levers. Whichever kiln you fire, the firing schedule builder gives you the segment plan to work from, and the witness cones tell you what the load actually received.