Bisque Firing For The First Time

[Whispering Grass]

I have recently purchased a new electric kiln - 100l top loader - it has a pre programmed bisque firing program. My clay is stoneware, and has the following description - 1220°C-1280°C
This jewelof a clay will bring new value to your creations. A smooth white stoneware,with the addition of fine molochite makes an excellent throwing clay suitablefor both oxidising and reduction firing. 10% molochite. As I am self taught I am not sure how long i need to bisque fire for - is it rule of thumb to increase temperature of 100 degrees per hour, up to five hours, then to increase after that, so my firing should be 8 hours ?

The description of the pre programmed bisque firing program in my user manual states the following :

T1 650

Time 1 6:00

T2 900

Time 2 0:00

Tume 3 0:20

Time 4 0

This makes no sense to me though ? Any tips at all would be really welcome as the books that I have do not go into any detail as to how long I need to fire, and to what temperature..

Thanks in advance

 

 

[Chris Campbell]

The pre programmed cycle will do an excellent job for you.

Using it every time will make your firings consistent and your results predictable.

 

What you need to decide is what cone you want to bisque to ...

Your clay probably has a recommended temp. so use that as a starting point.

Commonly used bisque temps are cone 08, 06 or 04.

 

I usually use a medium speed but some people prefer the slow.

Better to forget the fast cycle for bisque ware ... You need to take the time to

get rid of the impurities in your clay body.

 

Hope this helps.

[Whispering Grass]

Chris,

 

many thanks for this. The temp quoted on my clay is 1220°C-1280°C
 - not sure what cone this should be fired to - is there a chart I need to refer to re cones temperatures ?

Lorraine

[Deb Evans]

FYI

your clay temp converts to ^5-9 so its midrange - high fire. I converted celcius to F .

here's temp/cone chart in F degrees = http://www.bigceramicstore.com/Information/ConeChart.html

shows you how to set up cones to double ck/ see how even your high firings are.

[Chris Campbell]

Check in the manual that came with your kiln.

Most of them have cone /temp conversion charts in both C and F.

They might also have some suggestions for loading and firing that might be handy.