Rlucas on sun 11 dec 11
I have been told the following and want to know if you guys agree or
disagree and would like some
input to what is safe:
OPEN PEEPS AT 500 D.
PROP LID 1" OR SO AT 300 D.
OPEN KILN AT 130 D.
Thanks for any input
Verna Lucas
Pagosa Springs, CO
PS
I FIRE TO CONE 04 AND 6
William & Susan Schran User on sun 11 dec 11
On 12/11/11 12:19 PM, "Rlucas" wrote:
> I have been told the following and want to know if you guys agree or
> disagree and would like some
> input to what is safe:
> OPEN PEEPS AT 500 D.
> PROP LID 1" OR SO AT 300 D.
> OPEN KILN AT 130 D.
> Thanks for any input
Best advice.
Patience!
Leave the kiln closed until you can touch pots and kiln furniture with your
bare hands.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
gary navarre on sun 11 dec 11
Gary Navarre
Navarre Pottery
Navar=3D
Is 130F too hot to touch?=3D0A=3D0A=3DA0=3D0AGary Navarre=3D0ANavarre Potte=
ry=3D0ANavar=3D
re Enterprises=3D0ANorway, Michigan, USA=3D0Ahttp://www.NavarrePottery.etsy=
.com=3D
=3D0Ahttp://www.youtube.com/GindaUP=3D0Ahttp://public.fotki.com/GindaUP/=3D=
0A=3D0A=3D
=3D0A=3D0A________________________________=3D0A From: Rlucas YTEL.N=3D
ET>=3D0ATo: Clayart@LSV.CERAMICS.ORG =3D0ASent: Sunday, December 11, 2011 1=
1:19=3D
AM=3D0ASubject: [Clayart] Opening kiln after firing=3D0A =3D0AI have been =
told t=3D
he following and want to know if you guys agree or=3D0Adisagree and would l=
ik=3D
e some=3D0Ainput to what is safe:=3D0A=3D0AOPEN PEEPS AT 500 D.=3D0APROP LI=
D 1" OR =3D
SO AT 300 D.=3D0AOPEN KILN AT 130 D.=3D0A=3D0AThanks for any input=3D0A=3D0=
AVerna Luc=3D
as=3D0APagosa Springs, CO=3D0A=3D0APS=3D0A=3D0AI FIRE TO CONE 04 AND 6
KATHI LESUEUR on sun 11 dec 11
On Dec 11, 2011, at 12:19 PM, Rlucas wrote:
> I have been told the following and want to know if you guys agree or
> disagree and would like some
> input to what is safe:
>=3D20
> OPEN PEEPS AT 500 D.
> PROP LID 1" OR SO AT 300 D.
> OPEN KILN AT 130 D....
>=3D20
> I FIRE TO CONE 04 AND 6
>=3D20
Like everything else, it depends on your clay. My clay is a very dense, =3D
tight body. I often get dunting on large pieces if I open the kiln too =3D
soon. I like to prop the lid at 300 D. and open at about 150. Other =3D
potters, with a more open body, can be less careful. I have a friend who =
=3D
pops the lid while still red hot, puts a fan on it and then opens the =3D
lid completely at 500 D. It works for him.=3D20
KATHI LESUEUR
http://www.lesueurclaywork.com
Snail Scott on sun 11 dec 11
On Dec 11, 2011, at 11:19 AM, Rlucas wrote:
> I have been told the following and want to know if you guys agree or
> disagree and would like some
> input to what is safe:
>
> OPEN PEEPS AT 500 D.
> PROP LID 1" OR SO AT 300 D.
> OPEN KILN AT 130 D.
It's impossible to apply such a strict set of
temperatures to any and all firings! Every
circumstance is different. Furthermore, the
specificity of this list makes it seem authoritative.
(Beware of this! Con artists use that strategy
often...specific numbers make everything seem
like truth!) Physics doesn't work in round
Fahrenheit numbers, anyway. Any system that
makes it seem like it does is stupid.
Some clay bodies are more vulnerable to thermal
shock than others, so in general, more vitrified
clays need to be cooled more cautiously. Less
vitrified clay (like most bisque firings, or earthenware)
are almost immune to the ill effects of crash-cooling,
so the concern is less for the ware than for the kiln
itself. Glazes are generally sensitive to crazing
due to rapid cooling; a load of the same clay fired
to the same temperature without glaze might need
very little babying. Tightly loaded kilns will hold
heat in the work, and the thermocouple may give a
reading which is true only for the periphery of the
kiln, and if you prop the lid, it will be an even less
reliable reading as all that cold air displaces the
hot air now rising upward. Forget the numbers.
Pay attention to YOUR own results! The person who
told you these numbers is either trying to simplify
things for you (to the extent of obscuring the more
subtle truths of cooling), or is terribly ignorant
themselves.One of the worst habits that besets
contemporary ceramics is the way that some
practitioners, with the best of intentions, promote
(and believe) hard-and-fast 'rules' that get perpetuated
as Truth, instead of mere rules-of-thumb meant to
precede (and be replaced by) actual understanding.
My perceptions of the steps preceding kiln opening:
Don't open the peeps. This just causes isolated cold
spots in front of the lowest ones as a draft is created,
but doesn't do much to cool the whole kiln together.
Crack the lid just enough to listen. Do you hear
pinging sounds? Those are the sounds of your glaze
crazing from the inrush of cold air. Shut the lid! Whatever
your pyrometer said _before you did that_, now you know
not to open it at that temperature anymore with that type of
load. Wait for a lower reading, (maybe 100F lower) then
try again. Still pinging? Shut the lid again! Repeat, and
don't leave the lid open until you have no (or almost no)
pinging. You may also hear cracking noises of the kin
itself forming cracks. You don't want that, either. Just wait.
I prefer to wait until I hear no pinging, then open the lid to
do the final cooling. I prefer a kiln cool enough to unload
bare-handed, but bisque/unglazed earthenware loads may
not need it. For vitrified work, I'd rather wait. How long
depends on YOUR work , though, not mine. IS the work
looking crazed? Dunted? Then wait longer. No harm done?
Then maybe you can push it faster next time.Sure, there are
times when you want to get a load unloaded Right Now,
but is it actually essential, and worth the risk? Only you can
answer that!
You will quickly figure out what works with your clay and
glazes and kiln, and for each type of firing (bisque or
vitrification). Use that learning as your starting point for
each firing, but pay attention each time, as each load may
have different kinds of work in it, different glazes, etc.
'Rules' are only a starting point. Don't let them govern you.
-Snail
| |
|
