# I Need the Idiot Treatment on Kiln Firing Please...



## Simpler Times (Nov 4, 2002)

I may be getting a used kiln and some greenware and I know nothing about kiln firing. I've fired a lot of handbuilt stuff before in open fires but have never used a kiln. Unfortunately, the kiln does not include instructions. To further complicate the problem, I do not have access to cones or other accessories right now and the old greenware has been sitting around for five years or more gathering dust. Of course, I want to fire the kiln up as SOON as I get it in the door and not wait on ordering instructions, supplies etc. Immediate gratification ya know  

The greenware is from molds and white slip was used. It varies in size from Christmas ornaments to a couple of three foot tall cats and dogs. That is all I know about it! Is there any recipe for firing that I could use to insure best success on this first firing. What temperatures for how long etc. The greenware is pretty dusty. Does it have to be cleaned or will the dust burn off in the firing? I have no delusions that this firing will have no casualities. I just want to fire this stuff up to get it ready to paint/glaze. I need experience firing so that I can move on to doing my own stuff. I know nothing about the various paint/glaze options either so if anyone wants to clue me in or point me to a Ceramics 101 web site please do!


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## Wisconsin Ann (Feb 27, 2007)

first off...check the greenware for cracks. on the whiteslip stuff you get cracks pretty easily. 

generally, they use a low fire slip, so you'll be firing to 1950ish. there are a couple of good sites about firing techniques on line...i'll check for URLs and come back in an hour.

no cones, eh? that's a problem. bisque isn't as critical as the glazing tho. cones aren't very expensive, specially the small cones...I'd REALLY suggest finding some. even begging for a few from a local school or something


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## Wisconsin Ann (Feb 27, 2007)

what kind of kiln? does it have (or do you) some sort of temperature indicator? if so, you don't really need cones.

to raise the temps in the kiln, If you have multiple temp controls up and down (one for each heating wire) start off with "low" or 1. ramp up to 2 as you go...it's like the kitchen oven...just in layers. don't just turn on HIGH and let it run tho. go slow. Firing bisque takes a few hours..and you have to tend to it...every hour or so upping the temps...

kiln stacking is important. The more you put in the kiln, the slower you have to go to ensure that everything gets to the critical temps before you raise to the next temp. On your first run, you might want to stack kind of loosely. with bisque, you can stack pieces inside of other pieces. pieces can touch. I tend to fire things like tiles stacked up like bricks, so I have to fire slowly for those. larger pieces that have a lot of "air" room, you can go faster.

you'll want to fire slowly the first couple of hours. raising the temp to 220 slowly and then a "soak" to burn off the water vapor left in the kiln/greenware. The next critical temp is 464 or up to 500F(carbon burn off..the temp paper burns).again, you soak (leave the temp stable for maybe 20 minutes). next steps go faster...raising the temp to within 200degrees of your final temp. You can go a little faster here, 100degrees an hour (I often crank it to 250 an hour depending on how I've stacked the kiln), while stopping for a soak at around 850F. Then slow down again (back to 50-60degrees an hour) to the final temp. (gives all the kiln time to reach temp). Soak for another 10 minutes (to even out temps) and then shut off. leave it overnight before opening.

final temp...cone 03 (1960F to 1990ish) is good. 04 is okay. Your lowfire ornament glazes will be 05 or lower, so you won't be overfireing. just a sec here, i'll put up a cone=temp chart.


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## Wisconsin Ann (Feb 27, 2007)

PDF with colors of the various temps and explanations
http://www.potterymaking.org/KilnFiringLayout.pdf 

cone chart:
http://www.bigceramicstore.com/Information/ConeChart.html


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## Simpler Times (Nov 4, 2002)

Wow! Thanks for all the information Ann  You pulled out exactly what I needed with those charts. I did get the kiln. It is a Paragon with no actual temperature dial in terms of degrees. It just has low, med and high settings. I'm also a little concerned because about two fire bricks are missing just down from the top. This leaves about 12 inches of element exposed. The woman that sold it to me told me I could fire even with that exposed but that fire bricks are easy to replace. I hope she is right. I am going to try it out with the elements still exposed today! Keep your fingers crossed and if you hear a big boom call 911 for me! 

I did manage to get some cones (which are actually rectangular not cone shaped...) from a lady that has a shop pretty near me. I had no idea the shop was there but I called a paint-your-own place to try and beg, borrow, or buy as you said would be best. They use computerized kilns and didn't have cones. They did tell me about the other shop though so many of my problems are solved (I hope). Unfortunately, the woman was going on a two week vacation yesterday and I just caught her to get one box of cones.

Thanks again for your help! I'm sure I will be asking a lot more questions!


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