Barbara Arner on mon 12 mar 01
Hello,
Can someone help me? I am a beginner potter when it comes to using a kiln and
firing. I will be loading a kiln my first time on Friday and I am pretty much
the one that will be responsible.
I used three different clays making vessels on my wheel - Buff Stoneware,
White Stoneware, and Red Stoneware. I am using an electric kiln for the first
time and need to know what to keep in mind when firing. Please answer any
questions...in addition, any extra tips would GREATLY be appreciated.
The thrown pieces will not be glazed for the first firing. These clays either
take cone 5 or cone 6. Will it be okay if I use cone 5 (even for the ones
that say cone 6) for everything so it will all be able to go into one firing?
How long does one firing usually take - how long do I need to be near the
kiln/vacinity?
Is there any chance of the clay melting and ruining the kiln? Why would that
happen?
Is the top supposed to be open all the time?
If I also have hand-built greenware pieces that have underglaze on them that
need to be fired as well, can I fire them in the kiln with my thrown pieces
that are not glazed? Why would the glaze drip?
The cone number would still be the same if there were glaze on the pieces,
correct?
How long does it take the kiln to cool down?
Thank you very much for your help.
Happy Throwing, (:
Barbara
Rod, Marian, and Holly Morris on mon 12 mar 01
I've been in your shoes, as have we all! This is one of those times, I think
we would do you a disservice to try to answer the questions within the scope
of E-mail.
Based on your questions, I'd say the place you need to start is to carefully
read the owner's manual for your kiln (or really, any electric kiln, if
yours is not new and you don;t have the manual). This will give you all of
the information you need to get started. There are many issues you raise,
and I know my Skutt manual addresses all of these. Don't fire until you
read!
Yes, the clay can melt, and yes, you can do damage to the kiln, the ware, or
both. Also, see if you can get an experienced potter to walk you through
your first firing. I'm a great believer in the school of experience.
Marian in Michigan
Christina Zola on mon 12 mar 01
Good Luck! You really should have someone there who is experienced, to
watch over you! But here's some basics I've learned over the years of
loading student kilns...
Cones don=B9t have a huge temperature difference, and clays usually can be
fired to a range of cones, not just one specific one, so you should be fine=
..
As long as the underglazes are just that, glazes whose purpose is color, no=
t
glass, you should have no problems. Just leave some room (1/4 inch is fine)
around them in case. But it shouldn't run...
First thing to do is put the cone in the sitter. You might not be able to
reach, later.=20
When you are loading the kiln, make sure the shelves do not block the
sitter. Give it room so it doesn't get hung up on a shelf and thus, never
shut off.
Handle the pots carefully, as they are at their most fragile. Lift
everything from the bottom with two hands, don't ever grab something by the
rim.
Bisque firing -- you can stack pots inside each other for this firing. Be
sure the foot of the inside pot is resting on the bottom of the outside pot=
,
and that there is room all all the way between the two pots. Don't stack
pots that have slips or underglazes on them. It will transfer to the other
pot it's stacked in. (glaze firing -- DO NOT STACK POTS! someone did this=
,
once, and we had the most interesting, involuntary collaborative sculptures=
)
Measure your pots. Don't assume you can eyeball something that is close to =
a
stilt height. You'll just end up crushing the pot when you put the shelf
down. A yardstick is a wonderful thing. There should be a stick that fits
inside the kiln, so you can lay it from stilt to stilt and make sure nothin=
g
is too high before you put your next shelf down.
Leave the tallest pieces for last, to load on the top level. Measure that
tallest piece, and know where to stop in the kiln, so your shelf will be
high enough. Plan ahead!
There should be shelves in the bottom of the kiln. Your first level should
be around 4 - 5 inches, ie, don't do a tall stack or a plate stack for your
first level. You want air circulating down there.
Firing depends upon the kind of kiln, what kind of timers, programs, etc yo=
u
have. We give our bisque an eight hour soak, minimum, at low temperature i=
n
the bottom zone, to be absolutely sure all the moisture is out before we
begin firing. This is important, especially when you are firing other folks=
'
work -- could be air bubbles, could be thick as a brick. You don=B9t want
anything to explode on your watch.
Now, read the manual about firing times, turn ups, maximum temperatures,
etc. there should be a kiln log that shows you how long the kiln has been
firing. Set your timer for two hours past that time, and you won't get
meltdown, if the cone fails. We've seen some amazing meltdowns -- the
program in our computerized kiln failed and it looked like half baked
brownies meet lava flow.
Go find someone to help you, as there are a thousand other details I've
missed.
Let us know how it goes!
christina
Diane Echlin on mon 12 mar 01
Hi Barbara,
There are a few things that need to be addressed to answer your problem properly.
First, if you are bisque firing clays that range ^5 to ^6, you want to only fire
them the first time to about ^06 unless you plan to leave them unglazed forever, in
which case, fire to the lower cone.
Do you have cones, either the minis or the regular size?
Are you using any safety mechanisms like a kiln sitter or are you using a
computer-controlled kiln? Is your kiln vented or located away from your living
area?
Once you get the cone situation worked out, you want to heat the kiln reletively
slowly, with the lid cracked open and your peep holes unplugged. Slowly in this
case means about 100 degrees/hour to about 250 degrees (someone correct me if I'm
wrong.) This allows the water in the clay to evaporate slowly and dissipate with a
reduced risk of blowing your work to smithereens. Once you have burnt off all the
water, you can close the kiln lid and plug the peeps (I leave the top peep open in
bisque--just as a precaution) and let it rip.
I think we could be a little more helpful, and direct you to good sources of
information, if we knew more about your kiln (is there a sitter, do you have/use
cones, is there a computer controller, etc)
Also, the person who said to read (understand, learn, memorize, grock) the manual
gave you the best piece of advice---and if you don't have one on hand, contact the
manufacturer to get one!
Good luck!
Diane in CT
Barbara Arner wrote:
> Hello,
> Can someone help me? I am a beginner potter when it comes to using a kiln and
> firing. I will be loading a kiln my first time on Friday and I am pretty much
> the one that will be responsible.
>
> I used three different clays making vessels on my wheel - Buff Stoneware,
> White Stoneware, and Red Stoneware. I am using an electric kiln for the first
> time and need to know what to keep in mind when firing. Please answer any
> questions...in addition, any extra tips would GREATLY be appreciated.
>
> The thrown pieces will not be glazed for the first firing. These clays either
> take cone 5 or cone 6. Will it be okay if I use cone 5 (even for the ones
> that say cone 6) for everything so it will all be able to go into one firing?
> How long does one firing usually take - how long do I need to be near the
> kiln/vacinity?
> Is there any chance of the clay melting and ruining the kiln? Why would that
> happen?
> Is the top supposed to be open all the time?
> If I also have hand-built greenware pieces that have underglaze on them that
> need to be fired as well, can I fire them in the kiln with my thrown pieces
> that are not glazed? Why would the glaze drip?
> The cone number would still be the same if there were glaze on the pieces,
> correct?
> How long does it take the kiln to cool down?
>
> Thank you very much for your help.
>
> Happy Throwing, (:
> Barbara
>
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