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What's Your Bisque Firing Time, How Slow Do You Go?

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In reference to cone 06 thru 04, what do you think a 'slow bisque' comes out to in hours of firing? I've seen references to 10-12 hours, some in my area do 16 hours, what do you do and how fast?

 

I fire only my work and don't need to hurry pieces usually, so what goes in my kiln is usually bone dry. How fast could I be firing to 1910, which is what my glazes seem to like, without risking pieces? I understand that I would need to add time if any work is cool to the tough, I'm talking about a best case senario.

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In reference to cone 06 thru 04, what do you think a 'slow bisque' comes out to in hours of firing? I've seen references to 10-12 hours, some in my area do 16 hours, what do you do and how fast?

 

I fire only my work and don't need to hurry pieces usually, so what goes in my kiln is usually bone dry. How fast could I be firing to 1910, which is what my glazes seem to like, without risking pieces? I understand that I would need to add time if any work is cool to the tough, I'm talking about a best case senario.

 

 

I have an L&L easy fire e23t-3 kiln (~7 cu.ft) at home and use the slow bisque program. I bisque to cone 05 and it takes between 12 and 13 hours, depending on how dense the load is being fired. I do not pre-soak my work fired at home.

 

At the studio where I also fire, we also have L&L kilns and use the slow bisque program. Those are large kilns -- 10 cu.ft. and it takes about 14 hours to bisque. That includes a 2 hour preheat at 200 degrees. Lately, at the studio I've been doing a 10 to 15 minute hold at peak temperature (cone 05) -- just to make sure the pieces outgas. When we do scuptural work, we increase the preheat to 6 to 12 hours depending in the pieces to be fired.

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In reference to cone 06 thru 04, what do you think a 'slow bisque' comes out to in hours of firing? I've seen references to 10-12 hours, some in my area do 16 hours, what do you do and how fast?

 

I fire only my work and don't need to hurry pieces usually, so what goes in my kiln is usually bone dry. How fast could I be firing to 1910, which is what my glazes seem to like, without risking pieces? I understand that I would need to add time if any work is cool to the tough, I'm talking about a best case senario.

 

 

When firing for HS classes, my bisque would vary for the type of work we were doing, and the perceived thickness of the pottery. Often I would water smoke over night, then fire starting first thing in the morning, ending the firing at 5-6 when I left for the day. Some firings started with a water smoke first thing in morning til 9, then fire up til the 5-6.

 

If I felt the pottery was thicker as in some of the kids coil pottery I would fire as in the first listing, but let the setter turn the kiln off, I would guesstimate at the time needed and set the timer for one hour later. Final kiln turn up would be at 5-6.

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There are a lot of variables : kiln size, clay body, sculptural, tiles, fuctional. When firing beginning student work- usually set up 3 ramp slow bisque , 10 cu ft , 16 hrs or so. When it's my clay body/work can fire a bit faster> 12 hrs.

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Throw caution to the wind. Our clients want it now and expect us to defy all things logical. After all, we are artist and defying logic is kinda our thing. I take a faster approach to things without sacraficing quality. Here are my 2 methods. Either I work a collection and let it dry for a couple weeks. Load it up in the skutt km1018 on medium speed to cone 04. This is an 8hr firing and never had an issue. BUT... this takes a couple weeks. "Boring". If someone needs a burial urn you don't have a couple weeks. Here's what I do in such cases. Build or throw the piece. While on the bat or metal turn table, use a propane torch and constant motion to heat the piece while turning it. When it starts to smoke, turn off the torch and let the piece have a little smoke break. After one or two times the piece should be able to handle enough for some quick trimmin'g. In to the kiln it goes. Yes. Right when its finished. Here's the firing. Its long but its not weeks long like the boring method. Good luck.

 

90° F per hour up to 185° F

hold at 185° F for 4 hours

100° F per hour up to 600° F

200° F per hour up to 1922° F

Let the kiln cool on its own

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My bisque is a Skutt 1027 manual and I do not fire as long as people do here and it has been working well for me. I bisque both porcelain and stoneware in the same bisque to ^06. I know maybe not the best, but this what I do and it seems to work great. I also fire quickly, but my pots are bone dry and thinner has I only fire my own work.

 

I also only use ^10 clays as I fire ^10-11 Redux for my glaze fireing.

 

Here is the schedule I do.

 

 

1 hour - all there levels at low with the lid proped open with brick

1 hour - close lid and leave top plug open

 

After this time I keep watch and do the mirror test to ensure no steam is escaping sometimes this is a period of an hour sometimes less

 

I then click it to medium and run for 2 hours.

 

I then click to high and let the kiln sitter trun it off at ^06.

 

 

 

The entire firing is like 6-7 hours and I have only one pot crack on me and I think that was a clay problem not my firing.

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Testing Cone 6 Porcelain to achieve bisque cone 04-1971°F, start with absolutely dry ware.

Lid is propped open, top peep left open, and alarm set as reminder to close lid at 1000°F. At the end of firing top peep closed off. Kiln left to cool down to below 150°F or to room temperature before lid is opened.

Here is the program I have found to be the most useful so far-

 

Self Supporting Cones 03, 04, 05,

Degrees F

Segments- 4

 

RA1-80°

°F1-200°

HLD-30minutes

 

RA2-400° (Alarm sounds at 1000°F, lid closed)

°F2-1694°

HLD-00

 

RA3-120°

°F3-1900°

HLD-00

 

RA4-180° (In order to achieve 1971°F, in the last hour of firing the rate should be 180°F/hr, as per Orton)

°F4-1971°

HLD-00

 

Firing completed

 

Results: total firing time 7 hours 50min, cones correctly bent, distinct ringing sound when ware is thumped as opposed to the duller sound at the lower cone 04 temperature of 1945°F.

 

 

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