Craig Clark on sat 26 jan 02
Ok, I'm going to hang it out there for everyone to laugh at. I was told
years ago that the top peep hole in an electric kiln needs to be kept open
during the firing. I've always done this assuming that it is the way to go.
I close it up with some fiber as soon as the firing is finished. Is this the
right way to go or did I bite on the ole search for relative bearing grease
trick and not even know it?
Craig Dunn Clark
619 East 11 1/2 st
Houston, Texas 77008
(713)861-2083
mudman@hal-pc.org
----- Original Message -----
From: "Ron Roy"
To:
Sent: Saturday, January 26, 2002 10:43 AM
Subject: Re: Glaze test for Falls Creek Shino, cone 6, oxidation.
> The cooling rate will affect this glaze I think - well I know but I don't
> know how much and if it will be what you expect or want - I would think it
> would be better with slow cooling.
>
> Why not start posting the cooling time for it - say how long it takes from
> top temp (how far the cone bends) down to 700C (1300F.)
>
> better still why not include cooling time with all the glazes you post -
> the lack of this crucial information is part of the reason glazes don't
> travel well.
>
> If we do that when talking about glazes we will all be able to know just
> how slow or fast our kilns cool in relation to others.
>
> Keep in mind - the glazes in our book look VERY ordinary when fast
cooled -
> They are infinitely more interesting (I would guess salable as well) when
> slow cooled - as are - probably - some of your usual glazes as well.
>
> keep in mind - cooling depends on the type of kiln, how dense the stacking
> is, how old the kiln is (cracks), how well the lid fits, how well the
peeps
> are closed and even the ambient temperature in the room.
>
> What ever you do - don't leave the vent system on - at least don't have it
> sucking cool air into the kiln during cooling - if your vent manufacturer
> says to leave it on - contact them and ask how to get around the fast
> cooling effect.
>
> Let me reword that - if you are using a controller - maintaining a cooling
> rate - you can have the vent on - and even if you are just using your
> elements on low or medium - or a combination of low and medium - you can
> still have the vent system on - if it is left on you will have faster
> cooling if it is off you will have slower cooling.
>
> IMPORTANT !!! - if you leave a kiln on - you must not forget about it -
> check your kiln at least every hour - carry a timer with you - strap it to
> your forehead if you have to - always reset the timer as soon as it goes
> off - make it a rule - don't even look at the kiln till the timer is
reset.
> Firing a kiln is a part of the craft - firing your house or studio is not.
>
>
>
> >I use this glaze a lot and for me it is a light tan breaking to red
brown.
> >It does tend to deteriorate with age because of the gerstley, then it
turns
> >to brown. Think it may have something to do with the substitutions you
are
> >using. This glaze will sometimes crawl and leave the pulled away areas
red
> >brown, but I like the look. I use it over a dark brown clay that fired
to an
> >ocher. Have used it over white clays, but I don't like the look nearly
as
> >well. Had this glaze tested by Alfred and it was safe for me.
>
> Ron Roy
> RR# 4
> 15084 Little Lake Rd..
> Brighton,
> Ontario, Canada
> KOK 1H0
> Residence 613-475-9544
> Studio 613-475-3715
> Fax 613-475-3513
>
>
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Snail Scott on sun 27 jan 02
At 03:26 PM 1/27/02 -0800, you wrote:
>Skutt says to leave the top peep hole open all the time unless you have a
>vent.
Heck, I figure that's what the worn-down gap
between the top ring and the lid is for!
But seriously...
Some folks recently have suggested putting a slab
of refractory fiberboard under the floor of the
kiln. Sounds like a great idea to me, since I
tend to have a temperature gradient (cold on bottom)
that needs evening out during every glaze firing,
and since my kiln bottom is pretty badly cracked,
I figure the extra support couldn't hurt.
I'm wondering, now, whether that extra layer of
insulation would let me use a shorter kiln stand
or even eliminate it altogether. (My kiln shed
has a concrete floor.) How much insulation does
that sort of board provide, per inch? As a short
person, I'd love to knock a few inches off the
height of my kiln.
-Snail
Martin Howard on sun 27 jan 02
Another RULE to be discarded!
I do not have the peep holes open at all now. There are two or three sets of
three cones inside. I don't need to see them during firing. They are there
to tell me what happened during the firing.
The top is just open a crack up to 200C to let out water vapour,
then its shut completely until I open it again at 100C
or 150C if I'm being impatient.
Martin Howard
Webbs Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
01371 850 423
martin@webbscottage.co.uk
http://www.webbscottage.co.uk
Updated 20th January 2002
Dannon Rhudy on sun 27 jan 02
Craig said:
I was told
>years ago that the top peep hole in an electric kiln needs to be kept open
>during the firing. I've always done this assuming that it is the way to go.
>I close it up with some fiber as soon as the firing is finished. Is this the
>right way to go ........
I always leave the bottom AND top peeps open when firing the electric.
I want the oxygen flowing through, and it does not waste that much
heat. It is possible (listen to Ron Roy) to accidentally get some reduction
in your bisque kiln - or glaze- if the kiln is really tight. There's a lot
of organics to burn out of greenware, and if you are using paper clay
or other fiber clay (nylon fiber, for instance) they create a lot of
carbon during the burn off.
You done right, Craig.
regards
Dannon Rhudy
Cindi Anderson on sun 27 jan 02
I was just reading my Skutt manual and they said never to have the top and
bottom out at the same time, because you set up jet currents that can shock
the ware and screw up the cones in the path. You don't have this problem?
Skutt says to leave the top peep hole open all the time unless you have a
vent.
Cindi
Fremont, CA
----- Original Message -----
From: "Dannon Rhudy"
> Craig said:
>
> I was told
> >years ago that the top peep hole in an electric kiln needs to be kept
open
> >during the firing. I've always done this assuming that it is the way to
go.
> >I close it up with some fiber as soon as the firing is finished. Is this
the
> >right way to go .....
> Dannon said:
>
> I always leave the bottom AND top peeps open when firing the electric.
> I want the oxygen flowing through, and it does not waste that much
> heat. It is possible (listen to Ron Roy) to accidentally get some
reduction
> in your bisque kiln - or glaze- if the kiln is really tight. There's a
lot
> of organics to burn out of greenware, and if you are using paper clay
> or other fiber clay (nylon fiber, for instance) they create a lot of
> carbon during the burn off.
>
Paul Gerhold on tue 29 jan 02
Snail,
My big Skutt has been on a concrete floor with one inch of ceramic board
underneath for about five years. Works great and yes the bottom does seem to
lose less heat which of course it must since ceramic fibre has a higher
insulating value than air. Makes loading the kiln a whole lot easier too.
Do not however use ceramic fibre.Compresses at the edges, pushes up in the
center and makes the bottom crack. This was my first "good idea".
Paul
Stephen J Lewicki on tue 29 jan 02
Another good material to try (cheaper) is 2" of calcium silicate. It will
take 1200 Deg F (which is fine for this application) and is not-
compressible - even more so than ceramic fiber board.
A word of caution - this idea is fine on a cement floor but don't do it on
a combustible floor like wood. I know of one milliion dollar fire that
resulted from such a mis-application.
Stephen J Lewicki
President, L&L Kiln Mfg.
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