Question about electric to gas kiln conversion

[ferns]

I'm thinking about buying an old non-working electric kiln to convert to gas (like Simon Leach). My question is about the max temperature of a kiln. Is the max firing temperature of a kiln based solely on the limits of its electrical components, or can the body/case of the kiln not physically handle it? If I converted a kiln that said, "Do not operate past 2000 degrees", would cone 10 firings damage the structure of the kiln? (The kiln I'm considering is an old Evenheat 3220)

[Bill Kielb]

Generally electric kilns are rated and limited by the amount of electric power available and element life at their rated cone. With gas it’s really easy to supply lots of heating so generally easy to supply enough power to get to cone 10.

So in general the fire brick is fine, just a rating geared toward the kilns electrical capacity to produce enough heat. Having said that these conversions are generally fine, but not the most efficient or sturdiest or the easiest firing construct of a gas kiln. But they are economical, educational and generally can service many successful firings.

Edited October 28, 2023 by Bill Kielb

[Mark C.]

 I have made a salt kiln out of an electric. The bricks are all rated for 2400 so its a non issue for cone 10 as  Bill points out above

[davidh4976]

Typically the bricks are good to cone 10+ as others have said. If you haven't seen it yet, take a look at what's called the "TDI downdraft conversion". I did this conversation and am pretty happy with it. There is even a book with good instructions on the conversion, and a FB group for discussion. I have fired to cone 10 in six hours. 

http://www.sebastianmarkblog.com/2018/

[ferns]

Thanks for the information, everyone. Your replies were really helpful! David, I just joined that Facebook group. It's exactly what I was looking for.

[neilestrick]

Most electric kilns are built with 2300F bricks. They can handle cone 10, but they'll shrink a bit more and wear out faster than if you're firing to cone 6.

[Dick White]

A couple of random thoughts - As others have noted, the cone rating of the electric kiln is less about the bricks than about the amount of designed electrical power to heat the volume. But if an old kiln has a low design limit, e.g., your example of "do not heat past 2000F", that is probably a combined function of small kiln size and 2.5 inch thick brick. Those both can be limiting factors in the utility of the converted kiln.  You will lose some space to the burners and exhaust, and the thinner brick will radiate more heat to the surroundings. Electric to gas conversions fall into the down draft and updraft categories, I haven't heard of a cross draft conversion. Updrafts don't need much alteration beyond a burner hole in the bottom and an exhaust hole in the top, but they tend to fire unevenly. Down draft conversions require significant alterations of the interior for bagwalls and chimney walls that take up space, so start with a big kiln so you still have some stacking space.

[neilestrick]

HERE is a good conversion.