Sandi Nelson on sun 12 nov 06
This passed week has certainly been full of lessons for this noo-b potter=
=2E Thanks for the help on the firing=2C but would you believe we overfi=
red even while babysitting the kiln=3F How could this happen=3F=3F We s=
aw =5E6 beginning to move much earlier than expected=2E By the time we f=
igured we had to intervene=2C she was sitting at 9 o=92clock=85even befor=
e the soak began=85so we skipped on to the next ramp=2C however=2C =5E6 =93=
disappeared=94 so we skipped the remainder of the soak and went to the co=
ol down ramp=2E We thought we were all right=2C but later upon opening t=
he kiln=85craters=2C blisters=2C and odd colors=85plus =5E7 was at 9 o=92=
clock=2E Upon more reading we discovered we had one of the thermocouples=
in the Liberty Belle that =93could be=94 way off target=85so when we wer=
en=92t watching the witness cones we were overfiring=85lesson learned to =
babysit those cones!
=
I=92m in a dilemma=85I know most of you make your own glazes which I=92m =
sure we=92ll be doing later=2C but for now I have commercially prepared C=
ampbell and Spectrum glazes that are all rated =5E4-6=85 the Lagunas are =
=5E5=2E I have stoneware clays that are all rated =5E6=2E (Is there a =5E=
5 clay=3F) I=92m seeing that the glazes cannot go above =5E6=2C so my qu=
estion is=85is there a temp range that I can still get the glaze to matur=
e properly and not overfire the glaze=3F According to the Orton chart=2C=
my clay needs to reach 2228 F but the glaze needs to stay in a range bel=
ow that number=2E If I am firing only decorative pieces=2C will it matte=
r if the clay does not vitrify=3F (Should I fire these below =5E6 so the=
glazes won=92t overfire=3F) Must the clay for functional pieces (batter =
bowls=2C colander=2C mugs) be vitrified=3F =
=
We=92re understand much more to do with fitting the glaze to the clay bod=
y=2E=2E=2Ethanks to John=92s and Ron=92s book and reading the ClayArt pos=
ts! What a great resources this is! Thanks everyone!
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