Jump to content


Photo
- - - - -

Help KIln was set to hold for 35 hours instead of minutes


  • Please log in to reply
53 replies to this topic

#21 Pres

Pres

    Retired Art Teacher

  • Moderators
  • 2,123 posts
  • LocationCentral, PA

Posted 03 January 2012 - 09:52 AM

Well here are the pics......it was a small load thank goodness!!!


Whoa. .. . let me get your time frame straight, and some of the particulars of this firing. 1) does you kiln use a kiln setter, that you put a cone 6 cone in? 2) you turned the kiln off at 10:30 (am?)and opened it at 12:30(pm?). You used a runny glaze on the top edge of the pot, and other cone 6 glazes on the rest.

My comments:
On 1-when looking at the kiln setter-what is the appearance of the cone 6 cone? Is it bent, or melted to the brackets etc? 2) Opening a kiln with only 2 hrs of cool down time is detrimental not only to your ware, but the kiln itself. At the same time, because you have an L&L you may damage the element holders by opening the kiln too quickly. 3) If the setter kiln was not melted then you had a nearly normal firing. Your glazes look a little overfired, but then that may be the colors. I did notice some blistering on the outside of the batter bowl that usually indicates some form of firing problem. These could be form unpopped gas pockets from the clay body due to the over fire.

We all have been here. Back in the 90's When running consecutive firings, I overslept. leaving a kiln on high for 6 hrs. longer than than required. The pots all came out dark brown and bloated. None of them stuck to the shelf, none slumped so much as to touch others. My glazing and preliminary cleanup of shelves and pot bottoms ensured that even though I was over exhausted and lost a load, I didn't lose a kiln. Big lesson! I fire without a kiln setter, in an L&L. Everything I do with the kiln is manual. In my younger days that was OK, but now that digital control is out there and works well, I long to upgrade to that set up. Even then, I will be like a mother hen over a kiln, but will have a back up incase I oversleep.

For those of you that don't work in a HS environment: I also fired kilns for years in HS with a kiln setter. I know the standard admonishment that the kilns have to be watched all through the process-however, sometimes that is not possible. I would often start a firing on low the night before, water smoking the kiln til morning, put down the lid, 2 hrs later start turning the kiln up. Usually the bisque was not done when school was over at 3pm. Usually at 4pm it would still be firing, and would shut down between 4-5. This sort of thing was usually after the elements were in for a year or two. A glaze would start in the morning and not end until 6 at night, if I got it loaded the night before. If not, sometimes it did not shut off until 10 or 11 at night. Most time I was at school when the kiln shut off, but often it was too late for me to stay. As I did sets for the drama club, many nights I did not leave school until 10pm. Get up the next morning and do it all over again.

The last year I worked one month before retiring the dr. diagnosed me with T2 diabetes. No family history, not overweight, no other risk factors- Dr. believes I wore myself out! Now retired, no meds, diet and exercise only, BG numbers are normal-for now. So be careful folks!

Simply retired teacher, not dead, living the dream. on and on and. . . . on. . . .                                                                                 http://picworkspottery.blogspot.com/


#22 grayfree

grayfree

    Advanced Member

  • Members
  • PipPipPip
  • 55 posts

Posted 03 January 2012 - 10:12 AM

Pres I have a digital dynacontrol so you just program it for fast glaze or slow glaze and then any hold you want to add. I turned the kiln on at around 6 PM I checked it the next morning around 8am (at which time I didn't realize it was still firing....just wasnt thinking I guess) and then again at 10:30 AM that is when I shut it off after figuring out what I had done and that it was still firing. It cooled down until around midnight last night ....that is when I opened it. I cant get the rest of the pictures to load but I had one nice red saucer with some breaking of blue around the edge that was a dark red I had and put lusturous jade on edge. the little green saucer in the picure was waxy white covered in lusturous jade the my other peices where suppose to be golden rod chino and cedar chino......all that is a yuk brown. the batter bowl was firebrick with lusturous jade on lip.
All in all I will triple check all settings from now on and I guess buy some cones. Although cones would not have changed the outcome. I will get some goggles and get brave and peep in once in a while. thanks to all who have responded.

#23 teardrop

teardrop

    Advanced Member

  • Members
  • PipPipPip
  • 211 posts
  • LocationColorado

Posted 03 January 2012 - 10:21 AM

Tha lack of use of cones and the mistake in programming that led him to this predicament led me to believe that our friend grayfree was using the digital control exclusively to fire his work. This is how it is done at the college i attend as well. No cones are used in the small (digitally controlled) kilns unless a firing has gone awry (hasn't happened) or a test of the cone temps seems in order. Other than that, it's a >hit the Slow Bisque or Slow glaze button< kinda deal...and the pre-programmed menu runs through and completes the cycle "as programmed". the addition of an extra step was where it went wrong for grayfree. IMO. Had he just went for the slow glaze on cone 6 things would have been AOK.

glad ya didn't find a huge mess or any serious damage, grayfree.
Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind. Dr. Seuss US author & illustrator (1904 - 1991)

#24 grayfree

grayfree

    Advanced Member

  • Members
  • PipPipPip
  • 55 posts

Posted 03 January 2012 - 11:10 AM

your on the money teardrop your only booboo is that i am a girl.

#25 teardrop

teardrop

    Advanced Member

  • Members
  • PipPipPip
  • 211 posts
  • LocationColorado

Posted 03 January 2012 - 11:41 AM

your on the money teardrop your only booboo is that i am a girl.


It's that "Net" thing again. grayfree! Thanks for cluing me in.

be safe, be well

teardrop
Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind. Dr. Seuss US author & illustrator (1904 - 1991)

#26 Matt Oz

Matt Oz

    Advanced Member

  • Members
  • PipPipPip
  • 280 posts
  • LocationMichigan

Posted 03 January 2012 - 12:44 PM

Glad to see no sticking pots, and it looks like your skills are coming along nicely for only six months.

#27 oldlady

oldlady

    single firing an electric kiln to cone 6

  • Members
  • PipPipPip
  • 1,077 posts
  • Locationharpers ferry west va and pinellas park fl

Posted 03 January 2012 - 01:03 PM

to echo everybody but make a suggestion nobody has yet thought of. you must have gotten a manual with your new kiln, so CALL the telephone number listed on your kiln manual and discuss this with the expert at L&L. you did not say it was a hold time at the end of the firing, but everyone is assuming that is the case. my L&L has several options to enter hold times. i am also assuming you meant the hold at top temperature at the end of the firing and not the one to preheat and dry the ware before firing. the man at L&L is a lifesaver, well, at least a potsaver. he is very knowledgable and kind. he can help you understand what happened.

there is one other thing you might do. i know i am old and do things in a way youngsters scoff at, but try going to your local library and READING all the pottery books you can BEFORE your next firing. some of the OLD ones that tell you lots of info about the process of making pottery, not the flashy new ones about how to do a particular style or shape. this field is a constant learning opportunity for anyone who asks questions like how, why and what can i do now. after 35 years i have more questions every day.

your batter bowl looks very nice. you have a right to be proud of it.
"putting you down does not raise me up."

#28 grayfree

grayfree

    Advanced Member

  • Members
  • PipPipPip
  • 55 posts

Posted 03 January 2012 - 01:37 PM

thanks oldlady I did just that and a nice man called me back. we had a chat about how to enter the numbers. I read everyday about pottery mostly on the internet. I have a book or two and have ordered more. I will continue.

#29 Pres

Pres

    Retired Art Teacher

  • Moderators
  • 2,123 posts
  • LocationCentral, PA

Posted 03 January 2012 - 02:02 PM

thanks oldlady I did just that and a nice man called me back. we had a chat about how to enter the numbers. I read everyday about pottery mostly on the internet. I have a book or two and have ordered more. I will continue.


My experience is with the larger kilns, and some what older, they had a kiln setter and the programmed controller. Sorry about that, your time line also through me off without the mention of am or pm. I am sure that you have learned a valuable lesson that you won't repeat. It is lucky that nothing was really damage other than a few pots. Having to replace floor or elements or even element holders is a pain. Good Luck!

Simply retired teacher, not dead, living the dream. on and on and. . . . on. . . .                                                                                 http://picworkspottery.blogspot.com/


#30 metal and mud

metal and mud

    Advanced Member

  • Members
  • PipPipPip
  • 55 posts
  • LocationLas Cruces, New Mexico

Posted 03 January 2012 - 02:54 PM

I cant get the rest of the pics to load but you get the jest of the colors they are all about the same yuk brown.



Your pieces are pretty! I'm glad you didn't have a total kiln melt-down. Posted Image As a newbie myself, I feel I should relate a kind of funny kiln story. I have a used electric kiln (Paragon octagonal) that has a kiln sitter that has worked just fine. I'd toyed with the idea of getting a pyrometer because it was old, but hadn't. It fired just fine at cone 6 and seemed pretty reliable. I'd tracked the time it took for the kiln sitter to flip and it had been about 6 hours. In warm weather. For my latest firing I woke up in the middle of the night 8 hours after starting the firing (sorry, but it was the middle of the night) and it was still going. I panicked and stopped the firing, fearing that everything had been overfired. It turns out that it didn't reach cone 6 and the glazes were very weird. It was in December--I suppose the ambient temperature in my cold garage affected the firing time? I don't know! Anyway, I refired the pieces and they turned out just fine. I look forward to the experienced potters' comments. Would a pyrometer help?

#31 Arnold Howard

Arnold Howard

    Graduate, School of Life

  • Members
  • PipPipPip
  • 257 posts
  • LocationMesquite, Texas USA

Posted 03 January 2012 - 03:33 PM

I discovered I set it to hold 35 hours instead of minutes. I have cut it off now and it probably held about 10 hours.


It is a good idea to check Program Review every time when you are ready to start your kiln. As you watch the program in the display window, compare it with a written record of your firing. As you found out, it is easy to enter 35 hours instead of 35 minutes!

"The Checklist Manifesto: How to Get Things Right," by Dr. Atil Gawande looks like an interesting book. I haven't read it yet, but it pertains to this subject. According to reviews, the theme of the book is that it is easy to make a mistake by forgetting one little step. This is why pilots use checklists before they fly a plane. Has anyone here read the book?

Sincerely,

Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com

#32 Arnold Howard

Arnold Howard

    Graduate, School of Life

  • Members
  • PipPipPip
  • 257 posts
  • LocationMesquite, Texas USA

Posted 03 January 2012 - 03:41 PM

It turns out that it didn't reach cone 6 and the glazes were very weird. It was in December--I suppose the ambient temperature in my cold garage affected the firing time? I don't know! Anyway, I refired the pieces and they turned out just fine. I look forward to the experienced potters' comments. Would a pyrometer help?


A pyrometer would certainly help in tracking the progress of your firing. With experience, you can also tell the temperature by the color of light around the edge of the lid. I would be surprised if cold weather slowed down the firing significantly.

Sincerely,

Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com

#33 lacemuse

lacemuse

    Member

  • Members
  • PipPip
  • 11 posts

Posted 03 January 2012 - 03:58 PM

I just started firing bisque pieces with a small paragon. My new Skutt KM818 just arrived & is waiting to be wired. I'm scared to death to leave it unattended at the end of the firing - just wouldn't, but that's me. I read the manufacturer's instructions & the horrors of why not to leave it unattended & to definitely use cones. Not beating you up at all, but just saying I wouldn't. LOL! Your pieces that I saw are lovely by the way.

So you don't feel too bad about making a mistake though, here's the stupid thing I did.

I threw a bowl for the dogs. It was nearly a disaster at the throwing wheel, but I managed to trim it into a really cute bowl & save it. I just could NOT make myself wait that extra day to make sure it was completely dry (it had a thick bottom.) I knew better, but I wanted to get the firing done before the holiday, so I went ahead. Well, everyone knows the result - it exploded, & blew off the side of another piece in the kiln. I guess I just HAD to experience the sound of that explosion to be satisfied that it would indeed happen to greenware not completely dry.

When I heard the explosion & saw the dust come out the vents in the controller, though, I did panic. It was not a pretty picture when I opened the lid, but one I will never forget. The destruction to the bowl was total!!! I'm not saying it won't ever happen again, but it WON"T happen again because I hurried the clay! Lesson learned & I seem to learn a lot of them the hard way. LOL!

Mary

#34 flowerdry

flowerdry

    Advanced Member

  • Members
  • PipPipPip
  • 91 posts
  • LocationVirginia

Posted 03 January 2012 - 05:12 PM

Not bad...but then I like brown. What glaze is on the brown pieces? You are doing extremely well for 6 months into it. I must admit, I am quite surprised that you are already firing on your own. I am 2 years into it and just now thinking about a kiln, but feel like I need lots more information before I start that. Did other people take some time before they started firing their own pieces, or am I just a slow learner?

Doris Hackworth

"Promoting the joy of handmade pottery"


#35 grayfree

grayfree

    Advanced Member

  • Members
  • PipPipPip
  • 55 posts

Posted 03 January 2012 - 05:13 PM

Mary that is funny the way you tell it. Of course I have done that too. I made a beautiful large pedistal fruit bowl and to this day dont know how I did that. I put handles on each side and everything and then I made another big bowl thing for baking bread in. They had dried I thought for about 2 weeks and seemed dry to me so in they went and kaboom they went! Glad I didn't hear the boom or I would have been terrified! Cleaned up just fine and moved on. Now I learned from someone who does sculpture to do a preheat of 12 hours before bisquing and that is what I do whether I need to or not HAHHAHAHA.

#36 grayfree

grayfree

    Advanced Member

  • Members
  • PipPipPip
  • 55 posts

Posted 03 January 2012 - 05:18 PM

Flowerdry I just jumped right into to all of it. Took one class at the community college 1 night a week for 8 weeks then bought a wheel and set up my studio. Took the class a second time and now I am on my own waiting for another guy in town to get his studio up and going for classes. He will do some intermediate classes and individual classes. Thanks for the compliments..... It is not suppose to be a brown glaze I used amaco's firebrick and lusturous jade on the lip I should come out deep burgandy and blue.....

#37 flowerdry

flowerdry

    Advanced Member

  • Members
  • PipPipPip
  • 91 posts
  • LocationVirginia

Posted 03 January 2012 - 05:39 PM

Thanks for your reply, Grayfree. I have been taking the same 6 wk pottery course over and over again at my local community arts center, so I have seen a lot of people in the beginning stages of learning to throw. I can tell you that you are doing extremely well for the amount of time you've been learning. And you are very brave to jump right in there. Happy potting!

Doris Hackworth

"Promoting the joy of handmade pottery"


#38 Sojourner

Sojourner

    Advanced Member

  • Members
  • PipPipPip
  • 69 posts

Posted 04 January 2012 - 02:48 AM

I cant get the rest of the pics to load but you get the jest of the colors they are all about the same yuk brown.


Well the "yuk" brown actually looks pretty ok colorwise, but I think I see signs of pinholing? pits? blisters?

It might not be the color you wanted but it's not awful either. Any pinholing/pitting/blistering/flaking or otherwise messed up glaze qualities could be a problem however.

How might overfiring affect food-safety?

#39 Benhim

Benhim

    Advanced Member

  • Members
  • PipPipPip
  • 193 posts
  • LocationBattle Ground Washington

Posted 04 January 2012 - 03:55 AM

Holy giant jpegs Batman.

I have to say I disagree with you about the yuck brown part. You've got some amazing color going on there. You're also very lucky that your clay and glaze both held up to the extended firing.

BenCo Ceramics


#40 grayfree

grayfree

    Advanced Member

  • Members
  • PipPipPip
  • 55 posts

Posted 04 January 2012 - 08:15 AM

I have finally figured out how to resize my pictures so I have tried to reupload and get most of them in for those that were interested. there were just a few more but this is most of it.

Attached Files






0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users