Karen Sullivan on tue 26 sep 00
To get copper red, Steven Horn, who teaches at Riverside Jr. College does
the following. I might add he fires at cone 5, I fire at cone 11. It
doesn't matter which temperature.
Fire the kiln normally, turn the kiln off, and let it cool until about 1450,
or a dull red heat, easier to see in the wee hours of the evening.
At dull red, turn the kiln back on and reduce for 5-10-15 minutes.
The sounds you will hear will be terrifying, frightening but don't worry.
The process causes bright red and doesn't affect non-copper glazes.
give it a try.
My question is, I understand PV clay is used to develop red in glazes.
Why does it promote copper reds.
Carolyn Nygren Curran on wed 27 sep 00
But just what kind of terrifying noises come out of a kiln starting up at
dull red heat? I take it the process is not dangerous, but it sounds like
it.... Even if we're not supposed to worry about the sounds, clue us in
to what we can expect. (Humor the wimp, I guess that's what I'm asking).
Thanks for the info, in any case. CNC
Karen Sullivan on wed 27 sep 00
Not to worry...you will popping-cracking sounds...the comment was to ease
the anxiety, and we think of firing as a relatively quiet process. So
striking is noisy.
Give it a try and you will be awed by the red glazes.
The dangerous part is re-lighting the kiln, so go gently.
bamboo karen
good luck
on 9/27/00 7:30 AM, Carolyn Nygren Curran at cncpots@CAPITAL.NET wrote:
> But just what kind of terrifying noises come out of a kiln starting up at
> dull red heat? I take it the process is not dangerous, but it sounds like
> it.... Even if we're not supposed to worry about the sounds, clue us in
> to what we can expect. (Humor the wimp, I guess that's what I'm asking).
> Thanks for the info, in any case. CNC
>
> ______________________________________________________________________________
> 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.
>
Hank Murrow on wed 27 sep 00
Carolyn asks;
>But just what kind of terrifying noises come out of a kiln starting up at
>dull red heat? I take it the process is not dangerous, but it sounds like
>it.... Even if we're not supposed to worry about the sounds, clue us in
>to what we can expect. (Humor the wimp, I guess that's what I'm asking).
>Thanks for the info, in any case. CNC
Dear Carolyn;
No problem if there is truly color in the chamber. Just be SURE that the
air supply is shut when you turn on the gas. There will be no pop, and turn
off the air somewhat before you turn off the gas to avoid the pop then.
Regards, Hank in Eugene
Gail Dapogny on thu 28 sep 00
HANK (AND OTHERS),
I'm intrigued --not to be naive or anything--by your observation that the
air should be shut down first. Can you explain?
Also...how about when starting and shutting down a cone 10 gas kiln: I've
always pushed the start button, then turned on air, then gas (the warmups
have been on overnight so it is around 700 or 800 degrees f).
Shutting it off, I push the start (toggle) button first, then turn off gas,
then air. Sounds like this might not be so good. What would you say?
Thanks in advance.
----Gail
>No problem if there is truly color in the chamber. Just be SURE that the
>air supply is shut when you turn on the gas. There will be no pop, and turn
>off the air somewhat before you turn off the gas to avoid the pop then.
>Regards, Hank in Eugene
Gail Dapogny
1154 Olden Road
Ann Arbor, MI 48103-3005
(734) 665-9816
gdapogny@umich.edu
www.silverhawk.com/ex99/dapogny
Hank Murrow on thu 28 sep 00
Gail Dapogny wrote;
>HANK (AND OTHERS),
>I'm intrigued --not to be naive or anything--by your observation that the
>air should be shut down first. Can you explain?
>Also...how about when starting and shutting down a cone 10 gas kiln: I've
>always pushed the start button, then turned on air, then gas (the warmups
>have been on overnight so it is around 700 or 800 degrees f).
>Shutting it off, I push the start (toggle) button first, then turn off gas,
>then air. Sounds like this might not be so good. What would you say?
>Thanks in advance.
>----Gail
Dear Gail;
I should have qualified my remarks to apply to naturally inspirated burner
systems, rather than ones with blowers. Often, the mixers feed a manifold
with a mixture of gas & air. If one shuts down the air before lighting, the
mixture will be fuel-rich and burn slow and yellow____preventing a pop.
Same reason for shutting down air before turning off the gas. If the
manifold is purged of air the mixture will again be fuel-rich and not
likely to pop back in the manifold. In the case of mixers which have only
one flame retention tip, the rule still applies; as it is far safer to
light a fuel-rich burner than one which has a stoichiometric(read
explosive) mixture of fuel and air. And again, one is less likely to
experience a pop when such a burner has been purged of air before shutting
down. I usually wait about a minute (after I have shut the air) to turn off
the gas. While I have built about 140 kilns, I have never outfitted one
with safety devices like you mention in your note. Perhaps my experience is
too limited, Hank in Eugene
| |
|
