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The Mighty Electric Kiln

Updated on September 22, 2012

Welcome

Welcome to the Kiln Goddess' Clay Pit of Electric Kilns. Electric kilns are kinda like big, really powerful ovens. They are the least scary kiln to fire. There is no flame, no gas, no fire box, no loud roar, no drama. But she is powerful and can get just as hot so the electric kiln needs your respect.

The Electric Kiln

Electric kilns come in different shapes and sizes, top loading and front loading. They are rated for different firing temps/cones. So always refer to your manufactures specs before firing.

An electric kiln is heated by elements much like your oven. The elements in most electric kilns I have used are coiled spring looking wires running around the interior of the kiln walls. These elements become red and glowy during the firing.

Elements have a certain life span. You can expect to get only a certain amount of firings from your elements and then you will have to replace your elements. The higher you go to the maximum temp your kiln is rated for the shorter the amount of times your kiln elements will give you the results you want.

Your Electric Kiln Poll

What best describes your electric kiln?

See results

This Old Kiln

Used Kiln-Is it Worth it?

So you bought/got given a used kiln. It now sits in the garage/basement/shed...now what?

The first thing to do is look it over for a brand and model number. Look for a metal plate with some info on it, write down everything it says. Now hit the internet and look up the manufacturer.

Are they still in business? Perhaps they merged with another company?

Find a contact address(email or snail mail) and write to the company ask if they have copies of manuals for your kiln for download or for sale, give all pertenant info you gathered from your examination of the info you found on the kiln. Ask if they have any wiring diagrams, do they sell replacement parts.

So now you have some info about your kiln model. Now we need to know about your kiln. Look it over inside and out. If it has any age on it it is going to have some flaws, perhaps minor: chipped bricks, sagging elements, rust, etc, perhaps major: chunks of missing bricks, broken elements, frayed wires, damaged kiln sitter, bad switches, sagging floor or lid etc. Honestly almost everything can be repaired but the question is "Is it worth it?"

If it has a few minor fixable problems a used kiln can be a great money saver. If you are a DYIer with more time than money an old kiln with major flaws is likely a good opportunity to get a kiln on the cheap. But f you don't know much about kilns, electrical work, etc you might want to pass on a cheap/free kiln with too many major problems, they can be more of a headache than a solution to your kiln needs.

Buying a Used Electric Kiln - What to Ask and Look For

Not everyone can afford a new kiln. Shopping for a used you need to educate yourself on electric kilns and what to look for when you go a view a used kiln so you are less likely to end up with a kiln sized paperweight.

  • Size-What size do you need? Will a smaller size do for now? Be aware that when asking a seller about a kiln, size will be subjective when they say it is a 'large ' kiln, their large might not be your large. When calling about a used kiln get the inside chamber dimensions.
  • Style-toploader or front loader? Depending on the work you produce one may be easier to load for you. Also toploaders come in hex, square, rectangle and oval shapes. What would you prefer? What will you be able to settle for?
  • Age-How old is the kiln? Older kilns might have more problems.
  • Manufacturer-Is the company that makes the kiln still in business? This might make getting the right parts easier.
  • Model-Can you find a model number on that kiln? The manufacture can tell you a lot about a kiln before you buy if you have the model number.
  • Bricks-Check the bricks carefully. Look for chips, cracks, sagging floors or lids. Small chips are not a serious problem, cracks can be, eapecially in the floor or lid. If the floor or lid sags you will need a new one of them so don't pay a lot for this kiln.
  • Elements-Look for sagging or broken elements. Elements can be replaced so it isn't a deal breaker but if you aren't up for the extra cost or labor it might not be your kiln.
  • Switches-When you go to look at the kiln and if the kiln is in a place to actually be able to turn it on, do so, check to see if all the elements get hot. If they don't it could be a bad switch or bad element but either way it is extra cost and/or labor and needs to be considered in the price.
  • The Controller-This could either be a kiln sitter of a computer controller. If it has a kiln sitter, look to over, look at the posts, do they look right? Flop up the lever, make sure everything moves as it should. Many kiln sitter parts can be replaced so but consider the expense in the final offer. As to the computer controller, ask if they still have the booklets that came with the kiln to help you program the computer, if they don't ask the manufacturer if they have a online pdf or a manual you can buy so you know how to program the computer for you firings.

Used Kilns on eBay

Sometimes you can find a good deal on used kilns on ebay. Remember kilns are usually fairly difficult items to ship and personal inspection is advisable, often you can find someone selling a kiln within driving distance and willing to have you pick it up.

Where to Used Kilns For Sale

Ebay is always one place to find used kilns. Your newspaper classified is another. Another place to look is to call up a school that teaches pottery often they get calls about kilns for sale and will pass this info on to you. Here are a few online places to check to see if there are any local listings for used kilns. **Remember, if it isn't local you will need to ship it and kiln are big and the price to ship it to you might exceed the price you want or should pay for that old of a kiln.

My First Kiln

Adventures in Kiln Repair

My first kiln was a small very old used Paragon Kiln. I got it for free. It had at least one major known flaw...but I'll repeat...I got it for free :)

It had been accidentally over fired, not badly but the owner didn't know why it overfired and the kiln was so old she didn't want to invest in it any further. She offered it to me...a soon to be graduating BFA student. I was so thrilled I just took a quick look inside saw all the parts were where they should be and that there wasn't any melted down gobs of overfired stuff anywhere and said yes.

It went straight from the owners basement, to my truck, to my university's pottery studio. When In doubt ask your teacher.

After I got it unloaded I gave it a better look over and saw a problem right away. The kiln sitter was damaged. The small round rod that sits atop the set cone during a firing was not a nice round rod anymore but instead had oxidized until it tapered was pointed on the end. The rod no longer had the weight needed to fall through the cone and turn off the kiln at the proper temp. My professor confirmed this was likely the problem causing the over fire. A couple used parts and a helpful friend and it was fixed...or so i thought.

Now while at college I had no place to test the kiln. All the schools kilns were hardwired to the wall. No outlets for the kiln to be tested. My small apartment didn't support the right current but I was soon to be graduating and moving 600 miles away. The kiln, of course, would come with me and so it did.

So now a few months later and 600 miles away in my parents garage it could be tested. Hmmm...opps it isn't getting hot enough. I let it cool and tested each element the only way my novice brain knew how, I turn on each element in turn on high and waited for them to glow. One of the elements wouldn't glow red hot, it would get warm but not hot.

A trip to the neighbors brought a retired electrician to help me. He undid the screws to the switch box and pointed to one switch and said it was bad.

I got hold of information and got Paragon Kilns phone number and got a friendly guy on the phone. He helped me order the right part and it arrived soon after. With the help of my neighbor(he didn't see so well anymore) we got the new switch in. The kiln worked fine...yippee.

Now I still have the kiln but it was kinda beat up during the hurricane season of 2004. It now sparks in the switch box when turn on. I have no retired electrician to help me anymore. I'll fix it soon.

My Electric Kiln Bisque Firing Schedule

I'm often asked how to fire an electric kiln. I'm a rather conservative kiln operator. I think it is better to run it a bit longer on lower temps than to risk blowing your work up in the kiln because the hidden moisture didn't have time to burn off.

Most of the kilns I have fired are three switch kiln without a computer controller. Please refer to your kiln manual if your kiln is of a different configuration and remember this is the schedule that works for me you might find your work and your kiln needs another schedule.

My usual bisque schedule is as follows:

2 hours all switches on low with lid up*

2 hours all switches on low with lid down

2 Hours all switches on medium with lid down

Turn all switches to high and let it reach cone

If the work is unusually thick walled 1/2" and up or large I use a slower bisque firing schedule.

Bottom switch on low overnight with lid up*

2-4 hours all switches on low with lid up*

2 hours all switches on low with lid down

2 Hours all switches on medium with lid down

Turn all switches to high and let it reach cone

(*lid up refers actually to the lid down but propped open with a brick or 2" shelf support.)

Why Fire Thick Walled Ware Slower?

The important part of a bisque firing is to burn off the hidden moisture in the work. The thicker the walls of the ware the more moisture could be there and the longer it will take for that moisture to make its way to the surface. By slowing down the firing cycle you give the moisture more time to make it out of the walls. If the hidden moisture does not disapate before it gets too hot it will build up inside the walls and blow the side off your ware right off.

Why Fire Larger Works Slower?

Larger wares need to be fired longer to equalize the hot and cool places in the kiln and in your work. A large platter will heat faster at the edges because they are closer to the elements. You want the edges and the center of the work to equalize. Also the more space a work occupies in the kiln the more likely it will occupies a localized cool spot in the kiln, a longer preheat will allow the entire kiln to be an equal temp.

Cooling the Kiln

Open Lid at Own Risk

It is important not to open your kiln lid or door too soon. If you open your kiln to soon you could damage the work within, while this important to bisque kilns, it is even more so for glaze kilns as a glaze kiln opened to soon can result in crazed glazes or even cracked ware.

Recently I received a call about crazing glazes. I ceramicist I had been firing work for had gotten her own kiln and had fired her first load but had a problem: Her glaze crazed. Now she didn't have that problem when I fired her wares, she had checked the past work. She asked what was wrong. After a few questions regarding her firing and cooling procedure it was quite obvious she had opened her kiln too soon and removed the wares while still quite hot.

Here are my general rules about when to open and unload your kiln.

I do NOT open the kiln until I can place my ungloved hand on the outside of kiln lid/door and leave it there comfortably. I then open the lid about 2 inches and prop it open with a brick, I also pull the peep plugs at this time.

I do NOT open kiln all the way til I can place my ungloved hand palm up on the inside of the lid and leave it there comfortably. I then open kiln fully.

I do NOT take ware from the kiln til I can hold it in my ungloved hand comfortably. I then unload the kiln.

Be aware that the kiln furniture will still be quite hot as it takes them longer to cool than the ceramic work so wear gloves while handling the shelves and posts.

Safety Gear on Amazon

Kevlar gloves are perfect for unloading your kiln, they a generally more flexible than leather so you can easily get you fingers down and around kiln shelves so you can remove the shelves from kiln without knocking something over.

Kiln Repair - Eventually all good kilns need it

So your kiln needs a little tlc. Some things you can do so things you might want and electrician to fix...judge your skill level and make your own call. Here are a few webpage I found out on the web to help you.

How Much To Fire?

Often I am asked how much it cost to fire a kiln. There are a few variables like the size of kiln, the amperage, and the temp you are firing to. I found this handy cost calculator. So just plug in your numbers and you have a rough estimate.

Electric Kiln Extras - Everyone Likes Leftovers :)

Here are a few links that I didn't really think was essential info about electric kilns but some of the links have just such cool idea/pictures I couldn't not include them.

I welcome your feedback. Would you like something added? Know a good link or book? Did I manage to misspell something? Did you find a dead link? Let me know, afterall this Kiln Goddess isn't all knowing ;-)

Suggestions and Feedback

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    • profile image

      anonymous 5 years ago

      I can not locate any information on a "NOVA" kiln model KL24120 Serial#: 120 240v ac. It has a kiln sitter on it (model LT-3K) but still, I would like to have some info on the manufacturer so I know where I can get parts. Any thoughts?

    • Ivan Wozniak profile image

      Ivan Wozniak 6 years ago from England

      Good basic information about electric kilns and firing.

    • KilnGoddess profile image
      Author

      KilnGoddess 6 years ago

      @anonymous: You can use kiln/element pins to secure the coils back into the element channels. If they are sagging badly you might need to warm the element to make them soft and pliable. I have added this link http://www.ceramicindustry.com/Articles/Feature_Ar... where details the procedure.

    • profile image

      anonymous 6 years ago

      HI, the elements in my electric kiln have begun to sag quite badly, does this mean I should replace them? or is there a way of securing them into the kiln so that they no longer sag?

      thanks

    • KilnGoddess profile image
      Author

      KilnGoddess 6 years ago

      For a glaze firing I don't leave the lid up or plugs out at the beginning of the cycle unless I glazed the work less than 24 hours before I fire. The moisture that the glaze puts back into the ware needs to be allowed to evaporate before the firing cycle starts so the lid up will allow the kiln to preheat and slowly evaporate the moisture from the ware before the ware gets too hot. The computer controlled kilns programmed schedule doesn't really account for a raised lid tho(my kiln is manual), perhaps you could program a longer preheat cycle than normal and leave the lid up if you have more recently glazed ware(btw I would not suggest firing ware that was just glazed within the last 12 hours).

    • profile image

      anonymous 6 years ago

      Nice clear explanation of your bisque firing schedule. Is it as important to leave the lid propped (and spy holes un plugged??) in a cone 6 glaze firing? I have a small kiln with computer controls.

    • Sylvestermouse profile image

      Cynthia Sylvestermouse 6 years ago from United States

      Excellent information and advice! I used to love making ceramics, but I haven't for many years now simply because there is not a place close by with supplies and kilns. This makes me really want to seek out a ceramic store and just make the drive :)

    • profile image

      anonymous 8 years ago

      Thank you so much for your information. One thing; after the cone temp is reached, do you then just turn off the kiln or do you slowly reduce the temp?