I just heard from Donna Conley, and she seems to be hinting that a few students in the Piedmont Technical College Professional Pottery Program in Edgefield, SC. might make their way to the Dillsboro, NC Pottery festival. If that's the case, show me a school ID and I'll give you a 10% discount.
But more important ('cause I'm not all about marketing...in case you haven't gathered as much from this blog), please introduce yourself(ves). I'd love to hear about your school and its program.
We're still in the midst of a heat wave (five days of 90-plus temps), and I'm still firing the kiln. I loaded up yet another glaze firing this morning. While I was loading the kiln, Breeze was cooling off after his morning walk...
hey john. sorry about the heat wave...almost snowing here in montana. what size is your kiln and would you mind sharing your firing schedule? (i'll check prev. blog posts).
ReplyDeletei'm still working out my reduction schedule and am thinking of moving to 2 separate firings (i like celadaon but i also likes me some copper glazes that stay turquoise).
enjoy your day.
Hi Heidi,
ReplyDeleteMy kilns are pretty small -- the interior space measures 42" high, 36" wide, and 30" deep. I stack it in three rows (front to back) of towered shelves that are 10"X21", or (when I'm firing my 20 inch bowls) one back tower of 10"21" shelves and one front tower of 18"18" shelves. My burners come up from the bottom, so I have very little in the way of a bag wall. Most of the chamber is useable firing space.
I have two different firing schedules:
Matte iron red glazes and porcelain I fire to 010 and then reduce for an hour enough that a bit of blue flame licks out the bottom burner ports. Then I open the damper back up enough that the rest of the firing climbs with just a small blue/green flame coming out of the peep holes. I takes a full hour for cone nine to go flat, and nearly an hour for cone ten to go about 1/3 down. If the atmosphere pushes my firing faster (say it's cold outside and there's lots of available oxyger) then I'll let cone ten drop a little further. I'd get about the same effect if I held the kiln at a flattened cone nine for two hours AND a 12-14 hour firing as I would if I fired to a medium cone 10 for an hour and a half AND a total firing time under eleven hours.
I know that didn't make sense. Total firing time should be 11.5-12.5 hours in order to have a true cone nine firing.
My other schedule is similar to the first, but after cone ten is half way down, I then open the damper to a clean atmosphere and the kiln then fires up to to a flattened cone eleven in 15-20 minutes. This flashing doesn't do anything to the body, really, but it changes the appearance and texture of the glaze a great deal.
thank you so much for taking the time to answer my query john...you are a generous soul.
ReplyDeletei've been 'clearing' at the end of a cone 10 tip touching firing but thought it was just to let all the last nasties out of the glaze after reducing for the entire firing...i haven't heard it referred to as 'flashing'.
my kiln holds 3 stacks of 12 X 24" shelves about 50 inches high and i've got 4 antique venturis (side ports) running off a 500 gallon propane tank. a bit of bagwall and quite a bit of wasted interior space (car kiln). i'm taking about 12 hours per firing and using about 50 gallons of fuel.
i've fired 20 times now and am just getting the feel...no gauges so i mostly listen, smell and watch as far as consistency.
not that you wanted all the gritty details but i'm always interested in what other people's kilns are like.
thanks again for all of your great blogging efforts.
enjoy your friday.