Paul Reeser on wed 23 oct 96
ClayArters/Skutt Owners,
I am a new "basement" potter and trying to learn more about
my skutt 1027 with kiln master. I hope some of you
experienced users can help this rookie!
My question is on re-firing: I use the cone fire mode for glaze
firing to cone 6. Because I applied the glaze a little too thin
on some pieces, I'd like to add more glaze and re-fire to cone 6.
Do I need to do anything different when re-firing these re-glazed
pieces to cone 6? Is a slow candling required? If so, does
anyone have a ramp/hold schedule for this to share?
Any info would be greatly appreciated.
Thanks,
Lauren Bellero
Red Bank, NJ
Bob Kavanagh on wed 23 oct 96
Good morning Lauren
The first thing to remember when refiring your work is that serious cracks
might occur around 1050-1060 degrees farenheit as you increase your
temperature. Since you have a controller make sure your rate of climb
between say, 1000 and 1100, is slow. When I refire in my electric I get to
about 1040 degrees and then I hold for 10 minutes in order to ensure that
the kiln is uniformly heated and then I proceed slowly (e.g., 50 degrees
and hour) until about 1080 and then I go back to my fast schedule.
bob kavanagh
CP Dunbar on thu 24 oct 96
Bob,
>The first thing to remember when refiring your work is that serious cracksmight
temperature.
Would you care to speak a little more on this subject ?
What is the reason for the cracks ?
Also, what about all the silly pieces that I have left around the studio until
I found the correct glaze for them. Now they have dust or cosmic spit accumulate
on them. When these already bisqued, but dusty pieces are glaze-fired is there a
protocol to burn off the dust/cosmic spit or wash it off, or does it matter at a
thank you, sir ...............cp
--
CP Dunbar
Leesville, SC USA
address cpdunbar@concentric.net
Ron Roy on thu 24 oct 96
>----------------------------Original message----------------------------
>Good morning Lauren
>
>The first thing to remember when refiring your work is that serious cracks
>might occur around 1050-1060 degrees farenheit as you increase your
>temperature. Since you have a controller make sure your rate of climb
>between say, 1000 and 1100, is slow. When I refire in my electric I get to
>about 1040 degrees and then I hold for 10 minutes in order to ensure that
>the kiln is uniformly heated and then I proceed slowly (e.g., 50 degrees
>and hour) until about 1080 and then I go back to my fast schedule.
>
>bob kavanagh
Just to add my two cents worth to Bob's comment - he is refering to the
free quartz inversion at 573C and I second his warning. There may be some
cristobalite present - depending on the body - so a slow rise between 150C
and 250C would be wise as well.
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
Bob Kavanagh on wed 30 oct 96
Good morning CP
Free silica (silica which is to chemically bound to something else)
undergoes an important transformation at about 573 degrees celsius. It's
crystal strucutre changes from one state (called alpha) to another state
(called beta) and this change is accompanied by a change in volume. If you
heat a piece irregularly at this temperature then one part of the piece
will expand before another, and because the piece is already fired and
thereby fairly rigid, it can easily break.
If your dust is literally like house dust, it will just burn off. If your
dust is clay dust from your studio you should wash the ware before going
further.
Have a good day.
bob kavanagh
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