Firing times for an electric kiln

[MELSF]

I recently invested in a Cress ET911 electric kiln. It came with an instruction manual, which has been helpful regarding turning it on/off and settings. However, I've been unsuccessful in finding information regarding firing time. I need help!

 

I am using cone 5 B-Mix clay with cone 5 Laguna glaze. I've successfully fired two loads of greenware using the following settings: Cone 04 Med - I let the kiln run for 6 hours then turned it off.

 

Yesterday I fired (tried) my first glazed pieces. I set the kiln on Cone 4 Med and let it run for 8 hours. The temperature got up to 1752 before I turned it off. I checked my pieces this morning and the glaze hasn't melted, still a rough and unattractive. Can I re-fire? If so, for how long? Is there a way to ramp up the temperature at a faster pace, and if so should I do this?

 

In addition to assistance with this current problem -- how do you determine firing times for both greenware and glazeware? Is there a specific temperature the kiln needs to reach and hold at?

 

Thank you!

[Mark McCombs]

Hi Melsf,

 

 

 

Cone 4 is 2142 degreesF. So you under fired by quite a bit.

 

It sounds like you were manually firing your kiln. If so, you will need some pyrometric cones (always a good idea anyway) to measure the heat-work. In your case i would recommend a set of three cones ^3, ^4 and ^5. (assuming your target is ^4). If you kiln has automatic setting/programming, I would use them.

 

Unless you have a specific reason to fire at ^4, fire your ware to ^5 as it is rated for maturity.

Yes, you can refire your ware. Make sure you are reach the correct amount of heat-work.

 

Read up on the following:

 

Orton Pyrometric Cones

Heat-Work

Make sure read and understand the kiln operating instruction and how to use the automatic setting if available

 

 

Good luck!!

[Lucille Oka]

I checked the Cress manual and it is not as comprehensive as it should be. However, Skutt has always had very good manuals with lots of information that can help anyone fire a kiln. Here is a link to the Skutt KS-Manual-2002 (KilnSitter).

http://www.skutt.com/pdf/op_manual/KS_manual/KS_OperatingManual_2002.pdf

[Cass]

i run an 8 hour bisc to 03..this is for work that will then be Raku, so ive found it better to er on the side of caution

[Mark McCombs]

I checked the Cress manual and it is not as comprehensive as it should be.

 

 

I just looked at the manual too. I agree that it is not very detailed.

 

It does appear that the kiln has programable cone firing available.

 

MELSF - I would set your kiln to fire to ^5 at the medium fire rate.

Use pyrometric (self supporting) cones 4, 5, and 6 on a tile and position them so they can be viewed when looking through a peep hole.

 

[Kimmer2277]

I checked the Cress manual and it is not as comprehensive as it should be.

 

 

I just looked at the manual too. I agree that it is not very detailed.

 

It done appear that the kiln has programable cone firing available.

 

MELSF - I would set your kiln to fire to ^5 at the medium fire rate.

Use pyrometric (self supporting) cones 4, 5, and 6 on a tile and position them so they can be viewed when looking through a peep hole.

 

 

[Kimmer2277]

I have a manual Paragon kiln with a kiln sitter. I bisque fire at ^08, and glaze fire at ^5 & ^6, and while I'm pretty new to firing on my own, I've had luck with this schedule:

 

* For ^08 bisque: candle on LOW for 6-8 hours with lid cracked open. Close lid. Set timer (if you have one) for 8 hours. Keep on LOW for 2 hours; turn to MEDIUM for 2-3 hours; turn to High for rest of firing.

 

* For ^5 glaze I set timer for 10 hours and do low for 2.5 hours; Medium for 2.5 hours; High to shut off (about 3 hours). I always set my timer.

 

If you are like me and don't have a programable kiln, one thing I would suggest is buying a pyrometer. For about $100, they are a good investment (I use mine for Raku). I turn to HIGH on bisque when it reaches 1175.

 

Here's a good chart for cone temps: http://www.bigceramicstore.com/information/ConeChart.html

 

Good luck,

 

Kim