Stacey and Gary Ballard on sun 25 jun 06
Hi Everyone,
I was wondering if there was a hard rule on this one and if I have been
doing it wrong for the last 10 years. After talking to people at NCECA in
Portland I been questioning myself. I fire my work 03-06 when I am doing
either a bisque or glaze run, I have always left about an inch gap in the
lid open until the last hour of firing. Then I close the lid and it takes
between 1-2 hours to reach temp. and it shuts off (manual kiln). What are
the advantages to just firing the whole time with the lid closed or inch
open. I do keep the bottom and top peep holes unplugged.
Thanks in advance for you thoughts on this one.
Stacey Ballard
logan johnson on sun 25 jun 06
Hi Stacy
I've also been working with clay for the last appx. 10 yrs. but I've never heard of your method of firing. I have one question for you: Why do you fire your kiln this way? When I fire my kiln If it's a glaze firing I leave the kiln lid open for the first hour I was taught that lets the last of the moisture & some of the nasties out. I don't know how accurate this is but that's the way I learned & I've not heard anything to the contrary. Then I close the lid for the rest of the time. I use plugs in all but the top hole untill the kiln kicks off then I plug the top hole.
Just a curious gal in SMOKIN" (100 degree) Yakima Wa.,
Logan
Stacey and Gary Ballard wrote:
>>I have always left about an inch gap in the
lid open until the last hour of firing. Then I close the lid and it takes
between 1-2 hours to reach temp.<<
Stacey Ballard
______________________________________________________________________________
Send postings to clayart@lsv.ceramics.org
You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
Logan Johnson
Yakima Valley Pottery & Supply
719 W Nob Hill Blvd. Ste C
Yakima, WA 98902
509.469.6966
www.audeostudios.com
"Carpe Argillam!!"
Dannon Rhudy on sun 25 jun 06
I know of no advantage to having the kiln lid open
while you are firing. What is the purpose of it? It
should be sufficient to have the upper and lower peeps
open, if you are trying to insure a neutral firing.
It seems to me that it simply costs you heat and
electricity to fire with the lid open.
regards
Dannon Rhudy
Charlie Cummings on sun 25 jun 06
Hi Stacey,
The short answer: If you are getting the results you want, you
probably aren't doing it wrong.
The long answer:
Leaving the lid slightly open will allow more air to flow through the
kiln, creating a more oxidized atmosphere and allowing more organics
to burn out during the bisque. As for the glaze firing, many glazes
don't react differently in a neutral or oxidized atmosphere. Others
need a little air flow to ensure good results.
If your kiln has a vent, leaving the lid open is probably
unnecessary. The vent will pull in enough air to ensure a clean
firing. If your kiln is indoors, you really should have a vent. The
combustion products coming out of the kiln, Carbon Dioxide and Sulfur
Dioxide to name a couple, make the air temporarily toxic. The
sublimated metals that come out of the kiln during the firing will
coat every surface in the firing room, leading to possible long term
toxicity. If the kiln is outside, or in some other well ventilated
low traffic space, you may be fine.
Ten years of experience is a lot. If you are being safe and getting
the results you want...keep up the good work.
Charlie Cummings
At 02:09 PM 6/25/2006, you wrote:
>Hi Everyone,
>
>I was wondering if there was a hard rule on this one and if I have been
>doing it wrong for the last 10 years. After talking to people at NCECA in
>Portland I been questioning myself. I fire my work 03-06 when I am doing
>either a bisque or glaze run, I have always left about an inch gap in the
>lid open until the last hour of firing. Then I close the lid and it takes
>between 1-2 hours to reach temp. and it shuts off (manual kiln). What are
>the advantages to just firing the whole time with the lid closed or inch
>open. I do keep the bottom and top peep holes unplugged.
>Thanks in advance for you thoughts on this one.
>Stacey Ballard
Charlie Cummings Clay Studio & Gallery
4130 South Clinton Street
Fort Wayne, IN 46806
Charlie@claylink.com
260-458-9160
www.claylink.com
Maurice Weitman on sun 25 jun 06
At 11:09 -0700 on 6/25/06, Stacey and Gary Ballard wrote:
>I was wondering if there was a hard rule on this one and if I have been
>doing it wrong for the last 10 years. After talking to people at NCECA in
>Portland I been questioning myself. I fire my work 03-06 when I am doing
>either a bisque or glaze run, I have always left about an inch gap in the
>lid open until the last hour of firing. Then I close the lid and it takes
>between 1-2 hours to reach temp. and it shuts off (manual kiln). What are
>the advantages to just firing the whole time with the lid closed or inch
>open. I do keep the bottom and top peep holes unplugged.
Hi, Stacey,
This seems to be one of those issues without=20
consensus and even strongly-felt differences.=20
What a surprise!
This is my take:
Keeping the lid closed the entire cycle will=20
prevent the steel band around the lid from=20
corroding and will save energy costs and element=20
life due to running longer.
This presupposes that your ware is quite dry. If=20
it's wet, you should either keep the lid propped=20
until water vapor stops wafting out the opening.
=46iring in a dirty/wet unvented atmosphere will be=20
bad for pots and elements and maybe even their=20
connections, though, and I think you ought to be=20
using a negative-pressure (usually downdraft)=20
vent (see recent clayart postings about these).
I run my vent for the entire firing, all peeps=20
closed, and only keep the lid propped until the=20
ware's dry, and never above 220=BA when I'm biscing=20
ware that is not bone dry or have glaze that's=20
still kinda wet. My studio barely/rarely has=20
those nasty sulphur smells common without=20
external venting.
Regards,
Maurice (not really trying to make up for lost=20
time having been away from a computer for nearly=20
two weeks)
John Post on sun 25 jun 06
> When I fire my kiln If it's a glaze firing I leave the kiln lid open for the first hour I was taught that lets the last of the moisture & some of the nasties out. I don't know how accurate this is...
>
When I fire my electric kiln with the computer controller I go at 270
degrees per hour from the start up to 100 degrees below the final
temperature. Then I go at 100 degrees per hour that last bit.
When I fire a glaze load in and electric kiln without a computer
controller I load it up and turn all the switches on or the dials up to
high and then wait until the witness cones drop.
I use controlled cooling when the glazes need it.
There is no o need to leave a lid open on a glaze firing at the start,
and no reason to go slowly either.
No reason to leave peeps open on an electric if you have a kiln vent.
The ware doesn't need it and it creates a chance for there to be a draft
which could cause a dry spot on a piece from the glaze not reaching temp.
Bisque is a different story.
John Post
Sterling Heights, Michigan
Arnold Howard on thu 29 jun 06
----- Original Message -----
From: "Stacey and Gary Ballard"
I fire my work 03-06 when I am doing
> either a bisque or glaze run, I have always left about an
> inch gap in the
> lid open until the last hour of firing. Then I close the
> lid and it takes
> between 1-2 hours to reach temp. and it shuts off (manual
> kiln). What are
> the advantages to just firing the whole time with the lid
> closed or inch
> open. I do keep the bottom and top peep holes unplugged.
Venting your kiln prevents a host of firing problems.
However, I would experiment with venting for progressively
shorter periods. You may get good results with less venting.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
| |
|
