Lisa Clapp on fri 21 jul 00
Situation: Skutt electric kiln, envirovent, 3 holes drilled in lid as per
Skutt's instructions.
Has anyone ever had a problem with blemishes appearing on their pots which
sit directly below the holes in the lid? I've had these occur repeatedly and
just now figured out these round discolored areas the size of a quarter on
my casserole lids are exactly under the holes. Infuriates me! Any
suggestions out there?
Thanks!-
lisa clapp, watching morning mist rise off the Nehalem River in Oregon
taube wilson on fri 21 jul 00
Lisa,
I haven't see this happen, but I read about it somewhere(maybe
in my Orton vent manual? I recently bought a kiln myself and read
the manuals cover-to-cover out of fear that I'd do something
terribly wrong). Anyhow, the suggested fix was to put another
kiln shelf over your top shelf of ware to divert the airflow.
Or I guess you could just avoid putting anything under the holes.
Pain in the neck, I know.
Taube Wilson
Annandale, Va.
tpottery@hotmail.com
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Penny Hosler on fri 21 jul 00
Lisa,
Yup, you'll get "blemishes" under the cold spots created by the holes,
actually underfired spots. Always put a shelf above your ware to
deflect the air (and be sure to leave at least 1/2" between that cover
shelf and the lid - an inch is better). That top shelf will also even
out the heat distribution and avoid problems, like cracking from
too-fast cooling, in your top-shelf pots.
Penny in WA
> Has anyone ever had a problem with blemishes appearing on their pots
which
> sit directly below the holes in the lid? I've had these occur
repeatedly and
> just now figured out these round discolored areas the size of a
quarter on
> my casserole lids are exactly under the holes.
Gregory D Lamont on fri 21 jul 00
At 08:18 AM 7/21/00 -0700, you wrote:
>Situation: Skutt electric kiln, envirovent, 3 holes drilled in lid as per
>Skutt's instructions.
>Has anyone ever had a problem with blemishes appearing on their pots which
>sit directly below the holes in the lid? I've had these occur repeatedly and
>just now figured out these round discolored areas the size of a quarter on
>my casserole lids are exactly under the holes. Infuriates me! Any
>suggestions out there?
>
>Thanks!-
>lisa clapp, watching morning mist rise off the Nehalem River in Oregon
>
>______________________________________________________________________________
>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.
Lisa,
I have an L&L kiln with the Orton venting system--same type as yours. It
sounds to me like your vent is drawing too much air. The flow of air
should be such that the flame of a match, when held over a hole, is just
drawn into the hole. If that isn't the problem, your best solution might
be to arrange your ware so that the streams of air are not hitting the
pieces directly, or to use a diffuser of some sort--say a bisqued plate up
on props just under the holes to act as a deflector.
Hope this helps.
Greg
Matthew Blumenthal on sat 22 jul 00
Yep.
Someone suggested, on Clayart, that you put one last course of shelves over
the stacked pots. So you actually have the shelves breaking the airflow
over your ware. Worked like a champ for me.
At 08:18 AM 7/21/00 -0700, you wrote:
>Situation: Skutt electric kiln, envirovent, 3 holes drilled in lid as per
>Skutt's instructions.
>Has anyone ever had a problem with blemishes appearing on their pots which
>sit directly below the holes in the lid? I've had these occur repeatedly and
>just now figured out these round discolored areas the size of a quarter on
>my casserole lids are exactly under the holes. Infuriates me! Any
>suggestions out there?
>
>Thanks!-
>lisa clapp, watching morning mist rise off the Nehalem River in Oregon
>
>___________________________________________________________________________
___
>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.
>
***********************************************
Matthew Blumenthal
Fremont CA
Potter, Guitar Player, Kayaker, and
General Computer Nut
mattblum@pacbell.net
http://www.mattegrafix.com
ICQ 12691259
***********************************************
LESAINT1@AOL.COM on sat 22 jul 00
Hi Lisa,
This happened to me, and the problem is indeed the vent holes. I have
the Orton vent and was told by Tim Friedrich of Orton that I could close the
existing vent holes and drill new ones at the edges of the lid so that the
draft will go down the sides of the kiln instead of in the center. Or you
could put a kiln shelf over your top layer of pots.
Leslie St. Clair in Kentucky
Chris Schafale on sat 22 jul 00
Hi Lisa,
Ah yes, I had this happen to me at the community studio, and the
director swore it was something I did wrong in glazing Then
when I got my own kiln, I learned the truth. Yes, the blemishes
you describe are caused by local cooling from air coming in the
vents. The only solutions I know are to make sure the tops of your
pots are at least 3-4 inches below those holes, to use the top shelf
for smaller pieces and avoid the hole zones, or to use an empty
cap shelf over the top shelf of pots. Any one of these solutions
reduces the usable space in the kiln, but that seems to be the
price you pay....
Good luck.
> Situation: Skutt electric kiln, envirovent, 3 holes drilled in lid as per
> Skutt's instructions.
> Has anyone ever had a problem with blemishes appearing on their pots which
> sit directly below the holes in the lid? I've had these occur repeatedly and
> just now figured out these round discolored areas the size of a quarter on
> my casserole lids are exactly under the holes. Infuriates me! Any
> suggestions out there?
>
> Thanks!-
> lisa clapp, watching morning mist rise off the Nehalem River in Oregon
>
> ______________________________________________________________________________
> 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.
>
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
Liz Gowen on sun 23 jul 00
Thanks I think that finally explains a series of tall mugs I had put
in a circle on the top shelf under the holes in the lid. When I
opened the lid after the firing the sides facing out, away from the
holes were very exciting while the sides facing in just under the
hole looked ugly, underfired. This has always baffled me.
I now fire with the vent on only during the 1st part of the
firing and then shut it down and cover the top with kiln shelf
halves. I had been doing this to help bring it to temp since I had
to remove the one ring on the kiln because of my back . Made loading
possible but with the L&L this meant a ^10 rated kiln would only
make it to ^5. I plan to get a 2nd lid or someone suggested fiber
board since I don't like the idea of the blanket, since they fall
apart being moved so much. I notice the top ring of the kiln between
it and the lid has quite a glow when hot. Wonder if this is enough
space to eliminate the holes altogether or would it create new cool
spots on the pots nearby? Might be best to stick to my original plan
and shut the vent off at the higher temps.
Liz Gowen
.
> >Has anyone ever had a problem with blemishes appearing on their
pots which
> >sit directly below the holes in the lid?
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