I finally got the pyrometer connected up, and the right sitter cones, and all my test tiles made. I doing my first firing right now - ALL BY MYSELF, YIKES.
I have a used Skutt 181 I was able to purchase well within my budget (for a song). I loaded the test tiles from three different clay bodies along with cones on each shelf. My thinking is to test the clay bodies and to see if any shelf is hotter than another. While I was loading the kiln, I was thinking, "This is really small, I need a bigger kiln". My, oh my, what's a gal to do?
I put the sitter cone in the sitter and turned the kiln on. I started at 12:30 and kept it on low with the lid propped and the top peep hole open for two hours. It already wanted to climb over 200 F. How am I going to slow candle my handbuilt pieces if it gets hot so fast on low? I kept holding a mirror in front of the peep hole but never saw any moisture on the mirror, perhaps because the lid was open? Any and all advice would be greatly appreciated.
Next I turned it to medium, still with the lid propped open till I got over 650 F and all the smell seemed to disappate. This took another hour. Then I turned it up to high for about 10 minutes and closed the lid. The operating manual says to keep the top peep open at all times so that's the way it is now.
It is now 4:25 and I am already up to 750 F. At 4:30 I am at 1000 F. Maybe this means the kiln is in real good shape because it doesn't take very long to heat up. Maybe I'll post this and you can make comments and then I'll post some more - it's kind of scary here all by myself. Feel free to chime in now.
You're all probably all laughing and saying what's the big deal? But remember I am isolated out here in the middle of the country without a soul to give me any moral support or advice - all I have is YOU - what do you think - is it all ok?
I need a kiln 101 class. This is amazing though... how exciting for you, doing this. Hope you get some good, helpful support.
ReplyDeleteHi Amy, I just got my 101 self taught class. Actually the Skutt operating manual was pretty good with explanations and over the last year or so I have been reading and asking questions on all the forums. So I finally got a chance to fire it since I didn't have to go any where in the middle of the day and could devote the time to filling out a log and such.
ReplyDeleteIt is all over and is cooling down now, we shall see. I plan on turning around and doing a test glaze firing next to see how the glazes do on the test tiles I made up.
Sweet, sounds like your first firing went well for a bisque. The cones will tell you alot about your kiln areas. Remeber to take good notes since you enjoy experimenting with glazes, knowing how they fire will help you reporduce same. I have a few glazes that only do well in certain areas of my kiln with a normal firing schedule. I try and elimate those glazes though. I need glazes that fire cone 5-7, slow cool or normal ,etc. Otherwise I would be crazy trying to remember where to place each piece.
ReplyDeleteIt all sounds very promising. I hate those first hours when the thing goes up so quickly. I have a controller on my kiln (whose capacity is too big, so we are never happy) this controls the ramping up and down in temperature. My firing rules are as follows for what its worth:
ReplyDeleteAll this is in Celsius.
The drying process has to have completed by the time you reach 100 C (180F) because beyond that is boiling point and explosion, so it must be done slowly to this temperature. If you are glaze firing the same rules apply but the pots wont blow up if this is too fast rather it can loosen the glaze from the bisquit and can fall off or crawl.
Change and decomposition happens from 120 up to 573. Clay gets converted to alumino-silicate (different for every clay can be as high as 700)
The really critical time is just under 600 and I slow my kiln right down then so that it takes an hour to travel from 530 to 600 in order to avoid problems. If the bisquited body is subjected to a sudden expansion at 573 and a temperature rise which is too rapid at this point it can result in a crack. Called Dunting
After this point it is onwards and upwards to fusion which starts at 600.
I can’t wait to see if it all went OK. I am still pinting trasmission test cards and also doing a firing too today.
Hi Mary, thanks, I made up a kiln firing log so and I wrote all the temps down. Still not sure how to keep it from ramping up so fast. Do you have an automatic kiln for your slow cool or have to do it manually?
ReplyDeleteHi Kitty, thanks for all the info about the temperatures. I still can't see how I can slow the kiln down. I may have to prop the kiln lid higher or open my spy holes to keep it from rising too fast. According to my log every 15 minutes my kiln is going up 50 degrees and that is too fast at the lower end. Now that I am reviewing the log I may have to leave it on low longer to get through the 573 to 600 temperature climb and then after that turn it up to medium. Not sure what I will do about a slow cool yet either. I may have to turn the kiln on and off several times to achieve a slow cool. I will talk to the manufacturer today to see what they say.
Good luck with your firing - I am anxiously awaiting your transmission card tests. I went back and looked at your plate again and I see the mandala resemblence and feeling from the plate too - great work.
Hi Amy, Mary and Kitty, thanks for your encouragment. I just looked at the kiln and it is 150 F and it is 6 am. The kiln has been cooling over night. I think this will be a good schedule for me to fire one day and let it cool over night. I have some watering to do then I will open when it is completely cool.
ReplyDelete