Firing schedule for manual kiln

[spottylover]

I have enough nerve to try a firing again after last time's disaster.  

 

I'd like to get an opinion on this schedule to start with for bisque.  I'll take notes as I go along and tweak it from there.

Set timer for 12 hours.  Low for 2 hours / medium for 2 hours / high for remaining 8 hours or until (IF) the kiln sitter drops.

 

Any thoughts on what to do then for a glaze firing?  I was thinking 8 hours on timer.  1 hour on low / 1 hour on medium / 6 hours on high or until the kiln sitter drops.

 

Thank you for your feedback!

[Babs]

Have you got a pyrometer?

[spottylover]

No I don't.  It's on my wish list, though.

[Babs]

Colour in kiln can help you gauge the temp.

I would keep on low till red just appears. Then med ans high as above

Time that first section. If takes hours and hours wdll you might want to adjust.

This is for a bisque firing.

Pres has a lovely chart he has posted a few times over the years perhaps you will find that in searching here

[Mosey Potter]

I fire my bisque manually and have followed this schedule successfully for 25+ years. I load the kiln during the day. That evening, before going to bed (my studio is at my home), I put the kiln sitter up to 20 hours or so, then put the bottom element switch to Low for 8 hours. I put a one inch thick piece of soft brick under the lid so that it is propped open. The following morning I put the middle and top switches to Low, and close the lid, leaving the spy plugs out. After four hours all three switches go to Medium and I put in the spy plugs but leave the top one out for the whole firing. Four hours later all switches go on High. At this point I make sure that the kiln sitter has enough time on it to complete the firing. I don’t want it to prematurely stop the firing before my biscuit temperature has been reached. Over the years I’ve determined that once I put the switches on High it will take about five hours to reach temperature, so I always set the kiln sitter at six hours. I’m pretty anal when I fire my kiln, I have at least a month’s worth of work at risk and I can’t afford to lose a paycheck. So, I’m always around when the firing is occurring. My kiln is a big oval, I think it is 11 cubic feet. As always, know that what works for one clay artist does not always work for another, so do some testing with wares that are not critical until you learn what works for you. I learned this schedule,  by the way, from a production studio, the Blue Spruce Gallery (which is no more) here in lovely Bend, Oregon. Hope this helps!

Cheers, Owen

PS I glaze fire in my gas kiln so I can’t help you much there. 

[neilestrick]

On 7/8/2019 at 8:49 PM, Mosey Potter said:

I fire my bisque manually and have followed this schedule successfully for 25+ years. I load the kiln during the day. That evening, before going to bed (my studio is at my home), I put the kiln sitter up to 20 hours or so, then put the bottom element switch to Low for 8 hours. I put a one inch thick piece of soft brick under the lid so that it is propped open. The following morning I put the middle and top switches to Low, and close the lid, leaving the spy plugs out. After four hours all three switches go to Medium and I put in the spy plugs but leave the top one out for the whole firing. Four hours later all switches go on High. At this point I make sure that the kiln sitter has enough time on it to complete the firing. I don’t want it to prematurely stop the firing before my biscuit temperature has been reached. Over the years I’ve determined that once I put the switches on High it will take about five hours to reach temperature, so I always set the kiln sitter at six hours. I’m pretty anal when I fire my kiln, I have at least a month’s worth of work at risk and I can’t afford to lose a paycheck. So, I’m always around when the firing is occurring. My kiln is a big oval, I think it is 11 cubic feet. As always, know that what works for one clay artist does not always work for another, so do some testing with wares that are not critical until you learn what works for you. I learned this schedule,  by the way, from a production studio, the Blue Spruce Gallery (which is no more) here in lovely Bend, Oregon. Hope this helps!

Cheers, Owen

PS I glaze fire in my gas kiln so I can’t help you much there. 

Assuming you're not firing large or thick sculptures, you can easily speed up that firing schedule. 4 hours on low and medium is slower than you need to go. Cut those down to 2 hours and you shouldn't have any problems.

[Denice]

A slower bisque is important if you are firing hand built pieces or if you are using red or black clay.  Red and black clay can give you problems with your glazes if the organics aren't burned out.  I fire them to C04.    Denice

[Mosey Potter]

In reply to Neil, I have 3-5000 dollars of pottery in each bisque firing, and having worked with this schedule for over two decades I’m going to stick with it. I hear you that I could save a few bucks on electricity by shortening the firing but for me it’s worth the extra cost in peace of mind.

To the original poster, you might try Neil’s schedule and see if it works for you. Mine allows me to include mugs that I’ve attached handles to that morning (I work on deadline and sometimes you gotta push the boundaries a bit!) with no problems at all. I don’t like to make that a regular habit but it’s nice to know I can get away with it when I need to. Like I said in my original post, what works for one does not always work for another when it comes to working with clay. 

Cheers to all! Owen