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heva423

Old Kiln Help

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Hello all!

 

About 2 years ago i bought an older kiln off a friend (that knew nothing about it) and now i am trying to get it set up for my own use.  I have little experience with manual kilns and this has been a long process to finally get it working. It is an Econo J23 With an aftermarket 3rd tier in it.

 

My first problems with the kiln was that all of the elements needed replaced. So i did that.

 

Now my biggest problem is choosing the right clay and understanding when and how to work the manual kiln. All i have ever worked with was Automatic kilns. 

 

After a few trials, from what i understand it probably cools too fast. if i just shut it off, it will cool to around 300 in about 8 hours. (from a cone 5 temp)

 

The cone sitter is unfortunately broken so i bought a thermometer for temporary use until in fully understand what to do with my kiln. 

 

a few months ago i had someone send me a link to a new control panel that would just convert the kiln to automatic but i wasn't sure if that was safe to do or even worth it because it was $650.

 

Some questions that i have for anyone that can answer:

 

should i try to switch it to automatic or just leave it at manual?

 

If it stays manual, do i fix the kiln sitter or just continue to use the thermometer that i bought?

 

What is the best clay to use? i have always worked with high fire clay (cone 5-6) but i worry that the older kiln will struggle to reach that temperature.

 

Depending on the clay, do you have any suggestions on how i can regulate the temperature correctly. ( Turning it up at the right rate) and then how do i get it to cool efficiently?

 

Thank you so much,

 

Heather

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Okay, I'll be the first to ask for some more information. Suggestions on a good clay will depend on where in the world you are. If you let us know where you are, someone from your neck of the woods can offer suggestions. Second, you mention working high fire, which is usually the cone 8-12 range, not 05 or 06. A kiln struggling to reach cone 05 or 06 may have limited ceramic use. Is it a glass kiln? What are you using it for, and how often?

 

A cone sitter works on a slightly different principle than a thermometer or pyrometer, in that it measures heat work, not just temperature. It's more accurate for glaze work. Also, it's kind of a safety shutoff. I'd want one. And many more experienced people than I would consider a fully manual kiln a complete pain in the rear, but it is quite possible to fire one depending on the level of your patience and the time you have to put in. Firing it down could be a possibility, if less fuel efficient.

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Welcome to the forms.

 

I wouldn't spend money, to make the kiln automatic, if it's getting on in age.  If you replaced the elements, it should be able to get to whatever the kiln's original maximum temperature was.  Unless it has other issues, like poor insulation, or something of the like.  The manufacture's tag, should list the max firing temperature.

 

I'd recommend fixing the kiln sitter.  The pyrometer that you are using, only  measures temperature.  With firing ceramics, you want to measure heat work, which is temperature over time.  The cones on a kiln sitter do just that.  

 

The best clay to use, is the one that works best for what you are doing.  Are you throwing, hand building/ sculpting, etc?  I'm guessing you meant to say cone 5-6, when you said high fire, as 05-06 is considered low fire.  Even 5-6 is more mid-range.

 

Best of luck in your ventures.

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just re-read....i did mean cone 5-6. ( i get high fire stuck in my head because my ceramics teacher always referred to that clay as high fire and a different clay as low fire) My worries on it being able to reach those temperatures come from when it was originally installed in my studio. the wiring was not hooked up properly and i had it re-done a few months ago but have not been able to do a fire since. 

 

I am located in Pennsylvania. I am completely willing to keep it manual, i just honestly have a hard time understanding how to fire it properly. My struggles in getting it hooked up properly have just caused me a lot of frustration and my patience has gotten lower each time I've tried to figure it out. i just need some general guidance. 

 

If i remember correctly the kilns max temp is 2300. I do a lot of throwing but i also will hand build on occasion. I would like to find something that is good for both if possible. 

 

i am still somewhat new to the world of ceramics. All i have to learn from was High school classes, independent studies and a few advanced ceramic classes in college.  i was taught ceramic techniques but nothing about a manual kiln (As expected). 

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If you can go to 5-6, a good stoneware, will allow to throw, and hand build/ sculpt.  There are a lot of colors out there, from white to multiple shades of brown/ tan.  The also make some mid-range porcelains.  

 

If the kiln won't reach mid-range temps, you have a lot of low fire options, as well. 

 

I would still fix the setter.  It helps, especially if you are getting back into things.

 

To fire manually, you will still need cones.  You will have a cone one temperature lower than you are firing, one higher, and one at your desired cone temp.  Once the first cone bends, you know you are getting close.  You then check more frequently, to watch for your actual temp cone.  Once it bends, you shut the kiln off.  The last cone is the "I waited too long to shut the kiln off" cone.

Many potters use cones, even if they have an electric controller, just to make sure what should be happening, is happening.

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As far as firing manually, I'd look out some older pottery books.   They all talk about setting to "low" for x hours, the switching to "medium", then "high".   Even newer books rarely mention firing with an automated electronic controller. 

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You might get a controller that you plug into. Then you could use it on the next kiln when you graduate to it.

Meanwhile try to get the kiln setter working. You can use cones or your pyrometer. I recommend using both. Pyrometer can give you a false reading. If you can do that, you could then fire down. Manual kilns demand more watching. If you let the kiln drop from ^6 down to about 2050 you can turn it back on by gently lifting the lever and pushing the On button.. Hold it for 20 minutes on almost Hi or Hi if you don't have infinite switches, and then turn it off.

 

Marcia

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Hi everyone,

 

I am moving this thread to the "In The Studio" section of the forum, which is better suited for this topic, and where it will get more views.

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Once you get your kiln setter working you can use your pryometer to downfire and hold the temp.  When you get to know you kiln better you can get answers on the forum how to do it.   Denice

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Here is a firing schedule I use on my very old manual Cress B-24-H. I have only glaze fired this kiln 1 time as I have an Olympic 2327 HE for glaze firing. The bisque firing never goes over 13 hours and never have turned the top switch to high.

 

Bisque cone 04...

bottom    low    2 hours
middle    low    2 hours
top    low    1.5 hours
bottom    med    1.5 hours
middle    med    1.5 hours
top    med    1.5 hours
bottom    high    1.5 hours
middle    high    1.5 hours
top    high    finish        14 - 15 hours
 

 

Glaze cone 6...

all    low    2 hours
all    med    2 hours
all    high    finish

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My first kiln was a manual kiln, it was an L+L K18, which is an older and smaller version of OP's kiln. It had no problem reaching cone 5 and 6. Although possibly it cooled down faster than was ideal, though in my early years my work was not refined enough for that to matter much.

 

Agreeing with others here, I would repair or replace the kiln sitter, rather than spending $650 to upgrade it to an automatic. Using cones will be more accurate that the thermometer/pyrometer you are currently. Though the pyrometer will be helpful if you decide to slow-cool. 

 

My firing schedules were pretty much the same as dhPotter's.

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Since you already replaced the elements, I would go ahead and get the digital controller assuming the kiln bricks are in decent condition. You're going to be firing that kiln for several years, so you may as well go about it the way you want to. The digital controller can also be used on your next cheap kiln, assuming it can handle the amperage, so the cost per year of buying it will be pretty low.

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Hi, I have been firing a Skutt kiln for about 35 years & there are no electronics involved. It has a cone sitter & timer.

I fire to cone 6/7 & depend on large cones in a piece of clay positioned in front of a peep hole. I use cone 6 & 7. I put a small cone 7 in the sitter.

I tune the kiln up 1-2 hours on low & 1 hour between med. & high. It takes about 7-9 hours to reach cone 7 depending on the amount of pots inside.

I then turn the temp. to medium and set the timer to 1 hour it shuts the kiln off.

For the last 1-1 1/2 hours of firing I keep checking the cones so the kiln doesn't over fire.

For bisque I soak on low for 2 hours.

I keep the kiln shut overnight & prop it open in the morning until it's cool enough to unload.

Joy

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I, too, own a very old L&L kiln along with a newer computer controlled model. My old one is now connected to an Orton kiln controller to simplify matters, but it functioned just fine without it. The L&L quality has been remarkable. The interior of my (I believe 1972 model) is still intact. Only the elements have been changed. The kiln sitter and timer still function fine. My point being that your kiln is a good one and just being old doesn't make it inferior. The bricks are only 2 1/2 inch thick so you may need to learn to turn it back on after it reaches temperature as Marcia suggested to soak glazes.

 

Not sure what has failed on your kiln sitter. I have had contactors not turn on when the button was pushed in and was able to get things renewed with some WD40. Parts are available and you might even find them on eBay. If you are able to reach temperature now, using cones or a pyrometers, means all is pretty much well. The kiln sitter does make things easier and safer. I am in the habit of monitoring my kilns anyway, even the one with the computer controller. So a manual kiln really isn't that different, just switching from low, to medium, to high. Sometimes it is even better because you can judge when it's time to increase the heating based on what's happening, such as steam being released from greenware early in the firing. The computerized models do that automatically but you still need to use judgement in programming the ramps and set points. Just having it computerized doesn't mean things won't blow if not fired properly.

 

The kiln should be fine for any midrange stoneware cone 4-7, and worth repairing the sitter if the bricks, lid and base are still in good shape.

 

I am quite a fan of L&L kilns and probably would have bought more kilns over the years if they just weren't so good that they last so long.

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I happen to own a J236, which is similar to your kiln, more than you can guess. My kiln is probably one of very few that left the factory in PA without the kiln setter-special order. I have always believed in a longer cool cycle so ordered it so that it could be fired down (cooled slowly by ramping down the temp). I fire using cones which I peep through the peep holes. This allows me precise firings and coolings without the use of the setter. So your kiln even though the setter is broken, could be fired regularly. However, this often means late nights for me baby sitting the kiln carefully to make certain I do not over fire. It can be done.

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question about the "aftermarket 3rd tier".  is this a circle of blank bricks or does it contain elements?

 

if it is the blank ring, that makes the question entirely different and i hope the kiln guys will have more of an answer for you.  sounds like you are just beginning the process of becoming a potter.  you might search the internet for a manual on that particular kiln.  L &L was the manufacturer of many models of EconoKilns for many years.  they probably have some kind of archival records that might help.

 

L&L has technicians who are very helpful, call them.

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All these that talk of old kilns make me wonder about my Scutt c231. Called Stutt and was told they made that model for 7 years and stopped production 45 years ago. Just in the process of getting 6 new elements and 7 bricks, a new rod for the cone sitter and it should be ready to go. 

The cone sitter does not even have a model# on it and has the timer mounted on the side of the sitter.

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The timer should be a secondary shut off. You set it for a little longer, than it takes to reach the dresired cone. If the cone sitter fails to trip, the timer shuts off the kiln, avoiding over firing.

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