Firing schedule for Paragon A55B - too fast?

[arubyplant]

Hello!

I just did a bisque firing with my Paragon A55B which has a manual kiln sitter. I fired to 06 in only 3 hours and 15 minutes following the suggested firing schedule from paragon. Which was as follows:

1 hour - Low, Top peephole out, lid vented

30 min - Medium, top peephole out, lid vented

30 min - High, top peephole out, lid vented

Then just leave on high with peepholes in and lid closed.

Does anyone have any suggestions for the best way to slow this cycle down a bit? Or do you think thats fine for a bisque? I imagine with more pots in it, it will slow it down a bit but its a small kiln and doesn't hold that much. 

Thanks!!

Ariel

[neilestrick]

Yes, that's really fast, especially for a bisque. The best way to slow it down would be to spend more time on each setting. Since it only spent about an hour on high with the top closed, I'd spend more time on medium and let it climb slowly on that setting. It would be good to get a cheap digital pyrometer so you can see just what's happening in terms of rate of climb on each setting, but I'd try something like:

Low for 2 hours with peeps out and lid propped 1".

Medium for 2 hours with peeps out and lid propped 1"

Medium for 2 hours with peeps out and lid closed

High till done with top peep out and lid closed.

[arubyplant]

Ok  great. Thanks for the feedback! I am definitely planning to get a digital pyrometer. I'm used to larger electric kilns and understand the value of knowing what the rates of increase are. Would you recommend trying a similar schedule for a glaze firing?  Should I be trying to fire back down since it's such a small kiln and will likely cool quickly?

[Bill Kielb]

Since you mentioned rates, it’s a central point to the issue of firing. So once you have a good perspective of them schedules start to lose their mystery. Bisque rates generally don’t exceed about 250 degrees per hour with the length of time at a temperature being key to removing all the organics. Glaze firings can go much faster, generally 400 - 500 degrees per hour. So doing the math says bisque - in about 10-12 hour range. Glaze - probably 5-9 hours.

Cool down can affect glaze finishes, generally rapid cooling tends to make things glossy and slower cooling can make things appear more matte as crystals have time to grow. Firing down may or may not be necessary for your look with the exception of if this kiln cools so quickly your wares begin to crack.

Natural cooling I would guess is gonna be just fine for most, but you may decide to fire down for a specific look.

[neilestrick]

1 hour ago, arubyplant said:

Should I be trying to fire back down since it's such a small kiln and will likely cool quickly?

Small kilns cool a lot faster than med/large kilns, and that can definitely affect how the glazes come out. If you're also firing pots in a larger kiln, then you will probably need to slow down the cooling to get similar results. That can be tricky in a manual kiln, but with a pyrometer it's doable. It may be as simple as putting it back on medium for 2-3 hours once it reaches the peak temp. The hard part is making sure you're there when the sitter shuts it off so you can restart it. If the kiln is in good condition and you plan to use to for many years, it's a good candidate for a wall-mount digital controller.

[arubyplant]

Okay great. Thank you both for the detailed and prompt replies! 

My dad is also a potter and has a "special" glaze firing that is actually longer than the bisque - so I wasn't aware that bisque firings are actually typically longer.

It's in ok shape. I got it from a friend who had replaced a few bricks and the top elements but the bottom will eventually need some work.  However, I am interested in what the process would be to convert a kiln to a digital controller - do you by chance have any links on hand for a tutorial/instructions??

Thanks again - this has been very helpful and informative.

[Bill Kielb]

4 hours ago, arubyplant said:

I am interested in what the process would be to convert a kiln to a digital controller - do you by chance have any links on hand for a tutorial/instructions??

I believe this is your kiln  (https://216.198.210.227/files/wiringdiagrams/ACF12E7.pdf ) it’s a small kiln without a sitter so you are gonna need a way to turn it off at a desired cone. It’s actually fairly easy to do but the easiest way  (IMO) would be to purchase a wall mounted controller and simply plug this into it. There are several on the market and retail in the 500.00 -800.00 Rangę. http://www.clay-king.com/kilns/kiln_parts/kiln_controllers.html

If you are reasonably handy, you can build your own and likely spend 350.00 - 450.00 bucks but that would take some price sourcing research and building it in an electrically safe manner. It will never be UL / CSA / FM certified in the end though so totally relying on your abilities to stay electrically safe.

FYI - Previous common firing schedules discussed here.

 

 

[Goke]

Hi all

Can I use a Nabertherm F220  to do bisque firing.  I also need a easy guide to programming it.

[Bill Kielb]

18 minutes ago, Goke said:

Can I use a Nabertherm F220  to do bisque firing.  I also need a easy guide to programming it.

I don’t think the F220 is a good choice, it is a fusing furnace with a top temperature of 950c or about cone 08/07. As far as bisque schedules  there are many but a very simple one would be to program it to not exceed 100c per hour. Maybe contact Nabertherm to verify.