Scott Bennett on fri 1 apr 05
Does anyone have any experience with pinholing in an electric kiln at
low-fire temps. It appears consistantly on work which is glazed on the inside and
outside only. I've been cleaning the work before glazing, but no luck. Any
thoughts would be greatly appreciated.
thanks,
scottologist
John Rodgers on fri 1 apr 05
Scott,
I have found that most (but not all) of my pin hole problems have been
related to how I did my bisque firings. For me, it works best to fire
long and slow. I use a manual firing procedure, and set my kiln on low
and let it fire over night. Next morning, I slowly bring the
temperatures up over a period of 6 to 8 hours. I do this by seting my
kiln to medium. This setting allows sufficient time for a long slow heat
work. Eventually the kiln will reach temperature and the clay is
sufficiently sintered. I bisque fire to witness cone 06. When I glaze, I
fire slowly as well. This seems to work well for my principle glaze,
which is Floating Blue, a particularly finicky glaze. I cool down fairly
rapidly by putting a fan on the kiln, but I never open the kiln until it
has cooled to room temperature.
Regards,
John Rodgers
Chelsea, AL
Scott Bennett wrote:
>Does anyone have any experience with pinholing in an electric kiln at
>low-fire temps. It appears consistantly on work which is glazed on the inside and
>outside only. I've been cleaning the work before glazing, but no luck. Any
>thoughts would be greatly appreciated.
>
>thanks,
>
>scottologist
>
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william schran on fri 1 apr 05
scottologist wrote:>Does anyone have any experience with pinholing in
an electric kiln at
low-fire temps.<
Try a higher temp. bisque firing.
Bill
Cynthia Bracker on fri 1 apr 05
Try bisquing hotter. Pinholes are caused by gases escaping from the
clay through the glaze, leaving tiny holes behind. If you bisque to an
03 then glaze at 04 or 05 it should solve the problem
Cindy Bracker
Scott Bennett wrote:
>Does anyone have any experience with pinholing in an electric kiln at
>low-fire temps. It appears consistantly on work which is glazed on the inside and
>outside only. I've been cleaning the work before glazing, but no luck. Any
>thoughts would be greatly appreciated.
>
>thanks,
>
>scottologist
>
>______________________________________________________________________________
>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.
>
>
>
>
--
Cindy Bracker (ext. 12)
Bracker's Good Earth Clays, Inc.
1831 E 1450 Road
Lawrence, KS 66044
TOLL FREE: 1-888-822-1982
FAX: 785-841-8142
http://www.brackers.com
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Cat Jarosz on fri 1 apr 05
Hi Scott,
I am taking John Brits Glaze making workshop and we have been discussing
Geology and how our clay and glaze ingredients are mined and how one of the
ingredients in our clay bodies is the fire clay and how they mine this
stuff...
. think of the fire clay vein as a solid tube and you only want the core of
this material and want to leave a few feet on the edges... sometimes those
big earth diggers get to close to the edges and this is where SULFER is
which is what everyone is blaming for PIN HOLING.. Got some dirty fire
clay... most businesses are not as fussy as ceramics and a bit of sulfer is ok ..
oh that all our material was PURE.. that said the only way to get rid of
the sulfer is to burn it out ..
One has 4 chances to burn it out if you bisque and dont single fire..
going up and going down both in bisque and high fire... I am not sure the exact
temp that sulfer burns out but someone on the list should be able to fill
you in on that . go slowly thru this period and let it all burn out.
ps I know you have gotten a few answers to bisque higher and dont need to
know the particulars on why .. but just incase you have inquiring mind and
are ok to get it in layman terms ( I am not bill nye the science guy)
:oD Cat Jarosz who better get to work NOW....
http://www.guildcrafts.com/cat/
V)''(V woof & >^..^< mew; Chicks with beards rule !!!
(_o_)
\||/
Mike Gordon on sat 2 apr 05
Scott,
After doing low fire glaze firing in the H.S. I taught at for years I
found that pin-holing is caused by either a too low bisque firing or
not keeping the bisque at temp for long enough to burn out all the
impurities in the clay. I bisque at C04 and take at least 9 hrs to do
it. Another way to cure it is to hold the glaze firing at temp for an
hour or so to allow the pinholes to heal over. Hope this helps, Mike
Gordon
On Apr 1, 2005, at 7:00 AM, Scott Bennett wrote:
> Does anyone have any experience with pin-holing in an electric kiln at
> low-fire temps. It appears consistantly on work which is glazed on the
> inside and
> outside only. I've been cleaning the work before glazing, but no luck.
> Any
> thoughts would be greatly appreciated.
>
> thanks,
>
> scottologist
>
> _______________________________________________________________________
> _______
> 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.
>
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