Converting Electric Kiln To Gas

[Adam Simpson]

The summer i graduated from high school my ceramics teacher was replacing an electric kiln that was having trouble reaching temperature. because of my interest in ceramics she gave the old kiln to me as a gift (awesome). through taking various classes i had been able to continue firing pieces while the kiln collected dust in my garage. im now looking into trying to convert it into a gas kiln so i can continue to fire pieces over the summer. i am pretty inexperienced with firing and kilns in general as it has mostly been teachers who handled the firings. im unsure as to what kind of burner/ regulator/ whatever else i may need to make the conversion. im just looking to setup a very basic gas kiln, does anybody know what kind of burner system i should look into? also if anybody know where i can find good directions on how to actually convert my kiln that would also be appreciated. thanks.

[LawPots]

The summer i graduated from high school my ceramics teacher was replacing an electric kiln that was having trouble reaching temperature. because of my interest in ceramics she gave the old kiln to me as a gift (awesome). through taking various classes i had been able to continue firing pieces while the kiln collected dust in my garage. im now looking into trying to convert it into a gas kiln so i can continue to fire pieces over the summer. i am pretty inexperienced with firing and kilns in general as it has mostly been teachers who handled the firings. im unsure as to what kind of burner/ regulator/ whatever else i may need to make the conversion. im just looking to setup a very basic gas kiln, does anybody know what kind of burner system i should look into? also if anybody know where i can find good directions on how to actually convert my kiln that would also be appreciated. thanks.

 

 

I personally don't know anything about converting kilns; but you might take a look at a few of the youtube videos from Simon Leach. He recently converted a large electric kiln to a down draft gas kiln with an interior flue, and he has a number of different videos documenting the stages he went through to get it done. Take a look:

 

http://www.youtube.com/user/sleachpots

 

He mentions many of the parts he uses at various stages, as well as the principles that he's basing his decisions on. He also didn't put in a regulator between his burners, and in one of the videos he admitted that he should have. As he unloaded the first bisque firing, he points out some underfired work. He has older videos of a kiln conversion as well, where he put the flue on the outside of the same or a similar electric kiln. It's not instructions, but it's instructive.

[bciskepottery]

I would suggest reading these two books: 21st Century Kilns by Mel Jacobson and The Art of Firing by Nils Lou. Both give a good presentation of firing and different types of kilns, including conversion of electric to gas. Depending on what cone you want to fire to (6, 10) and what type of fuel (propane, natural gas), etc. will dictate what type of burners, enclosure, vents, etc. you will need.

 

You might also want to check around some local studios and talk to those who fire gas, perhaps see if you could watch/assist a couple of firings to see what is involved. The Youtube videos are interesting and informative, but there are a lot of details that don't make it into a short clip.

[Marcia Selsor]

I saw an interesting conversion made by putting the cylindrical kiln on its side. In a magazine , PMI or Clay Times, I saw a wood fired kiln made of old electric kilns.

You can make a burner with black pipe , drilling small holes (minuscule) for propane or larger for Natural gas.

I used a squirrel cage blower from Graingers on the end of a 2.5 inch pipe with a capped 1/2 inch cross piece for the orifices. I used a drill press at the local HS to drill the orifices.

Best to check how many btu's you need to hit whatever temperature you wish to reach. Then figure cubic feet and what fuel you are using.

Easier is to buy burners from Mark Ward who will tell you how many BTUs you'll need.

 

Marcia

[kilndoc]

I've done this type of conversion a number of times, and it works out quite well; provided your expectations are reasonable for the materials.

 

 

There are many sets of instructions out there for converting an old electric kiln to a raku kiln, and that is where I would have you start. Look at Steve Branfman's book Raku: A Practical Approach, for a step-by-step guide with some nice pictures. The principals and the steps are really the same, you just need to get the burner rating figured out. For that, I refer you to The Kiln Book by Fred Olsen for the charts about BTU requirements, and to Mark Ward at Ward Burners for a safe burner system. YES you can build your own burner (I've done it too), but if you haven't ever done it before, PLEASE leave it to the experts. Saving a couple of bucks just isn't worth the potential cost...

 

 

That said, here are a couple of important points to remember:

 

1) Most electric kilns in North America are made of K23 IFB (or equivalent). This brick is NOT designed to stand up to heavy reduction atmospheres. Light to moderate is fine, but unless you coat the kiln brick with ITC (or something similar), you won't be able to get those GREAT shinos or those Malcom-Davis-Style carbon-trap glazes without SEVERELY reducing the life of the brick. The bricks tend to just fall apart.

 

2) Don't expect the sheet metal, screws, handles, or turnbuckles on the burner port side to last for very long. Also, just get rid of the hinge. It WILL rust out rather quickly and can break while the lid is open. Better to put additional barn-door handles on the lid and just remove it for loading/unloading.

 

3) You should expect to loose about 1/3 to 1/2 of your interior space to a combustion chamber. Again, I refer you to The Kiln Book by Fred Olsen. You CAN save this space if you create a Bourry-Box either beside or below the kiln to act as the combustion chamber, but you will loose some effeciency.

 

4) Plug EVERY SINGLE HOLE that is not being used for burner inlet, spy hole, or exit flue with ceramic fiber. Be thorough when looking for them. Even small holes will have fire shooting out of them when the kiln is reducing. I have a pair of work boots with a burn hole in them from one that I missed....

 

 

5) YES you should have a chimney stack on top of the lid with a damper (if its an updraft)...YES its a pain to stack every time...NO you shouldn't skip this step...

 

 

 

Good Luck.