Susan Schultz on thu 8 jul 99
This question is for anyone doing large scale sculpture and electric firing.
I am glaze firing for the first time in a new oval kiln with an
Orton Unitemp controller. I have done a number of bisques,
and programmed a very slow schedule that works. I would like to
hear from anyone who does large sculptural work and has a
schedule for low-fire glaze firing and slow cooling. Also, is
there anything published that discusses firing with controllers?
Thanks,
Susan Schultz
Stonington, Ct.
David Hendley on thu 2 dec 99
The only way to determine your best firing schedule
is to try different things until you find what you like.
I think candling a kiln overnight, as opposed to an
hour or two, makes no difference as to the length
of the firing or the results.
So what? Who cares what I think? Try it both ways
and see what you like.
I think that the first thousand degrees don't have any
effect on the finished look of the firing.
Try it fast and try it slow and see what you think.
Whatever works.
I think that many of us, with home-built kilns particularly,
just accept what the kiln gives us. If the firing takes
12 hours, so be it. If it takes 9 hours, fine.
Actually, there's something to be said for this kind of
kiln; you just let it do it's thing.
You don't have to think about firing schedules.
If you're firing reduction, there's also something to be
said for design flaws. After all, reduction is inefficient
burning.
My previous kiln (wood fired) was in this category. All
I had to do was fire it. No damper needed, stoke full bore
the whole time, and the pots came out looking good.
Now that we have more experience, understand things
better, and have new and more efficient materials at
our disposal, we can build more efficient kilns.
An efficient kiln takes longer to learn.
If you just let 'er rip, things can go too fast.
This is where the experimentation comes in. You, the
potter, can be more in control.
But, now you have to think about what you want to do.
My current kiln is like this. It took a while to get it
figured out, but, man, I love having a little more control.
It's kinda like trading in a Ford Escort station wagon
for a Mustang. With the Escort, you just floor it to go
70 m.p.h. With the Mustang, it's possible to go TOO fast.
--
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com/
----- Original Message -----
From: mel jacobson
To:
Sent: Wednesday, December 01, 1999 2:14 PM
Subject: firing schedules(long)
| ----------------------------Original message----------------------------
| have been thinking a great deal about the history of my firing
| schedule....it is long. almost 40 years in this house with the
| same kind of kiln. same gas pipe, same burners. the bricks have
| been changed around, configured differently now and again, but
| basically the same kiln.
|
| the more i dwell on it, the more i feel that i am trapped in a system
| based on gas pressure, stack, flu and weather.
|
| i could probably take an hour out of my firings, but rather think it would
| do little to improve things.
|
| most of my firings last about 10 hours...it just sorta takes that long.
| i start my kiln about 4 a.m. like the quiet time, alone time with the
| kiln. i only have about a pound of gas pressure, it is low and slow.
| use the old denver burners i got in 1960. big lazy, very nice burners.
|
| i ran my own gas line from the house, just used a hack saw and cut
| the pipe, put in a T and went through the concrete block...has worked
| just great.
|
| because of the lack of intense gas pressure the kiln just sorta fires
itself.
| i hold back some gas for the final push, sorta need it for cone 11.
|
| so much of my firing schedule is based on what the kiln is, how it fires
| depends on weather, wind, high and low pressure.
|
| i chuckle when i hear tony talking about me firing fast.
| it is a grandpa speed kiln, but fires even, 4 cone pats going over
| together.
| and makes good pots.
|
| i cool slow, re/light at 1700 for about 15 minutes.
| crack the door at 500f.
|
| take out pots the next afternoon.
| (of course i have been known to melt plastic flashlights peeking in the
kiln.)
|
| in so many ways, i think i stumbled on a good system years ago.
| long before i had any real knowledge of the science of firing, oxyprobes,
| etc. lucky.
| i have teased nils for years that i had the very first double venturi
| exit flu.
| i just did not know how, or have any brick that would span two bricks.
| so, just went with a flu exit about 38 square inches.
| it seems to be just right.
| the kiln fired to cone 10 in nine hours, the first time i fired it.
| it has worked basically the same for 40 years.
| when i built that first ifb kiln, i had never seen one, only a plan
| by a guy from iowa named mckinnell. he changed my life.
|
|
| i think ron roy built his first kiln about the same time that i was
| building mine...he still fires his the same way, same speed.
|
| i have fired many other kilns....most with very high, near 10 pounds
| of pressure and find they almost always have their own minds.
| i try to get folks to cut the pressure, slow things down a bit.
| flame spewing from every port....roaring fire. one has to be careful
| about burning your face off to see the cones.
|
| i think many folks out there have mis/interpreted nils' argument.
| he fires under a great deal of control, understands kilns as well
| as anyone on this earth....
| what he tells us is; you do not have to baby the kiln for hour after
| hour in the early stages.
| why candle for hours and start real slow...you know, hardly any flame.
| 6 hours to cone 012.
| he just starts the kiln, full gas, gets the thing going.
| then the kiln evens out and gets rolling.
| he can easily cut hours off a firing and still do it perfectly.
| and he can prove that all the didddling around in the early stages
| is just that....didddling around.
| and i believe that, trust that.
| many commercial ceramic engineers will confirm that.
| but, we are creatures of our habits, our art...and we
| are not commercial engineers...we do things alone.
| we do things our way. we have no alternative,
| it takes years for old tales to clear from our heads.
|
|
|
|
| so, i do not know what is best for any of you.
| find a schedule that works.
|
| nils will tell you over and over...most flu's are too big.
| gas wasters.
| stacks are often the wrong size, add or take off three feet.
| many people fire with too much gas, just over power it.
| firing is about finding balance....sorta like throwing, you
| find rhythm. then make it work.
| fear is still the big enemy, far too many people are frightened
| of their kiln.
| get over it. there are pots to fire.
| do it.
| mel/mn
| i am not speaking for nils, just giving you what is in his book.
| read it, and olson. and listen to marc ward.
| they know what they are talking about.
|
|
| http://www.pclink.com/melpots
| from minnetonka, minnesota, u.s.a.
Corinne P. Null on wed 8 dec 99
Sorry to be so slow responding to this thread - been saving up the good ones
to review.
OK, I understand going slow on a bisque to get all the yuckies out.
About fast firing that glaze load... don't we have to be careful going
through 1063F quartz inversion (expansion and contraction?), and 1400-1800F
for blister healing?
>From sunny, warm, NH. Winter still hasn't come to visit.
Corinne Null
Bedford, New Hampshire
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.UKY.EDU]On Behalf
Of David Hendley
Sent: Thursday, December 02, 1999 11:17 AM
To: CLAYART@LSV.UKY.EDU
Subject: Re: firing schedules
----------------------------Original message----------------------------
The only way to determine your best firing schedule
is to try different things until you find what you like.
I think candling a kiln overnight, as opposed to an
hour or two, makes no difference as to the length
of the firing or the results.
So what? Who cares what I think? Try it both ways
and see what you like.
I think that the first thousand degrees don't have any
effect on the finished look of the firing.
Try it fast and try it slow and see what you think.
Whatever works.
I think that many of us, with home-built kilns particularly,
just accept what the kiln gives us. If the firing takes
12 hours, so be it. If it takes 9 hours, fine.
Actually, there's something to be said for this kind of
kiln; you just let it do it's thing.
You don't have to think about firing schedules.
If you're firing reduction, there's also something to be
said for design flaws. After all, reduction is inefficient
burning.
My previous kiln (wood fired) was in this category. All
I had to do was fire it. No damper needed, stoke full bore
the whole time, and the pots came out looking good.
Now that we have more experience, understand things
better, and have new and more efficient materials at
our disposal, we can build more efficient kilns.
An efficient kiln takes longer to learn.
If you just let 'er rip, things can go too fast.
This is where the experimentation comes in. You, the
potter, can be more in control.
But, now you have to think about what you want to do.
My current kiln is like this. It took a while to get it
figured out, but, man, I love having a little more control.
It's kinda like trading in a Ford Escort station wagon
for a Mustang. With the Escort, you just floor it to go
70 m.p.h. With the Mustang, it's possible to go TOO fast.
--
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com/
----- Original Message -----
From: mel jacobson
To:
Sent: Wednesday, December 01, 1999 2:14 PM
Subject: firing schedules(long)
| ----------------------------Original message----------------------------
| have been thinking a great deal about the history of my firing
| schedule....it is long. almost 40 years in this house with the
| same kind of kiln. same gas pipe, same burners. the bricks have
| been changed around, configured differently now and again, but
| basically the same kiln.
|
| the more i dwell on it, the more i feel that i am trapped in a system
| based on gas pressure, stack, flu and weather.
|
| i could probably take an hour out of my firings, but rather think it would
| do little to improve things.
|
| most of my firings last about 10 hours...it just sorta takes that long.
| i start my kiln about 4 a.m. like the quiet time, alone time with the
| kiln. i only have about a pound of gas pressure, it is low and slow.
| use the old denver burners i got in 1960. big lazy, very nice burners.
|
| i ran my own gas line from the house, just used a hack saw and cut
| the pipe, put in a T and went through the concrete block...has worked
| just great.
|
| because of the lack of intense gas pressure the kiln just sorta fires
itself.
| i hold back some gas for the final push, sorta need it for cone 11.
|
| so much of my firing schedule is based on what the kiln is, how it fires
| depends on weather, wind, high and low pressure.
|
| i chuckle when i hear tony talking about me firing fast.
| it is a grandpa speed kiln, but fires even, 4 cone pats going over
| together.
| and makes good pots.
|
| i cool slow, re/light at 1700 for about 15 minutes.
| crack the door at 500f.
|
| take out pots the next afternoon.
| (of course i have been known to melt plastic flashlights peeking in the
kiln.)
|
| in so many ways, i think i stumbled on a good system years ago.
| long before i had any real knowledge of the science of firing, oxyprobes,
| etc. lucky.
| i have teased nils for years that i had the very first double venturi
| exit flu.
| i just did not know how, or have any brick that would span two bricks.
| so, just went with a flu exit about 38 square inches.
| it seems to be just right.
| the kiln fired to cone 10 in nine hours, the first time i fired it.
| it has worked basically the same for 40 years.
| when i built that first ifb kiln, i had never seen one, only a plan
| by a guy from iowa named mckinnell. he changed my life.
|
|
| i think ron roy built his first kiln about the same time that i was
| building mine...he still fires his the same way, same speed.
|
| i have fired many other kilns....most with very high, near 10 pounds
| of pressure and find they almost always have their own minds.
| i try to get folks to cut the pressure, slow things down a bit.
| flame spewing from every port....roaring fire. one has to be careful
| about burning your face off to see the cones.
|
| i think many folks out there have mis/interpreted nils' argument.
| he fires under a great deal of control, understands kilns as well
| as anyone on this earth....
| what he tells us is; you do not have to baby the kiln for hour after
| hour in the early stages.
| why candle for hours and start real slow...you know, hardly any flame.
| 6 hours to cone 012.
| he just starts the kiln, full gas, gets the thing going.
| then the kiln evens out and gets rolling.
| he can easily cut hours off a firing and still do it perfectly.
| and he can prove that all the didddling around in the early stages
| is just that....didddling around.
| and i believe that, trust that.
| many commercial ceramic engineers will confirm that.
| but, we are creatures of our habits, our art...and we
| are not commercial engineers...we do things alone.
| we do things our way. we have no alternative,
| it takes years for old tales to clear from our heads.
|
|
|
|
| so, i do not know what is best for any of you.
| find a schedule that works.
|
| nils will tell you over and over...most flu's are too big.
| gas wasters.
| stacks are often the wrong size, add or take off three feet.
| many people fire with too much gas, just over power it.
| firing is about finding balance....sorta like throwing, you
| find rhythm. then make it work.
| fear is still the big enemy, far too many people are frightened
| of their kiln.
| get over it. there are pots to fire.
| do it.
| mel/mn
| i am not speaking for nils, just giving you what is in his book.
| read it, and olson. and listen to marc ward.
| they know what they are talking about.
|
|
| http://www.pclink.com/melpots
| from minnetonka, minnesota, u.s.a.
Ron Roy on thu 9 dec 99
Hi Corinne,
I don't think there is a problem with ware going through the quartz
inversion on the way up in a glaze or bisque firing. It can be hard on your
shelves and bricks - fast firing through the cristobalite and quartz
inversions however.
If you are going to speed up your glaze firings towards the end you will
probably have to up flux your glazes to get the same melt and smooth them
out properly. A better strategy for glaze firings is to extend the heat
work towards the end of your firing - particularly the soak.
There is an advantage to having less flux in glazes - better durability
because you have more silica and alumina but it means you need to extend
the heat work so the fluxes have enough time to do their work.
Keep in mind - it does not take losing many pots to cancel out any fuel savings.
RR
>----------------------------Original message----------------------------
>Sorry to be so slow responding to this thread - been saving up the good ones
>to review.
>
>OK, I understand going slow on a bisque to get all the yuckies out.
>
>About fast firing that glaze load... don't we have to be careful going
>through 1063F quartz inversion (expansion and contraction?), and 1400-1800F
>for blister healing?
>Corinne Null
Ron Roy
93 Pegasus Trail
Scarborough
Ontario, Canada
M1G 3N8
Evenings 416-439-2621
Fax 416-438-7849
Les Haworth on wed 9 jun 04
If you are a potter or ceramic artist i'd like to see your firing
schedules. For bisque and for glaze or if you single fire. Also please
include the atmosphere as well and what type of kiln you fire in. (Gas or
electric.)
Thanks so much. Les H.
P.S. Please send of list to les@lagunaclay.com
| |
|
