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knowing when to trust a tool

updated wed 26 oct 11


Liz Gowen 1 on tue 25 oct 11

Part 2 of my ^6 reduction firing: I put 4 pots from that R firing into my
test oxidation kiln and slowly refired it to cone 6. Everything that was
crusty bubbly and mat even though the cones were bent identically came out
smooth, glossy as they should have and the copper pinks retained their
color. I talked to Paul Geil about the firing and he said if it is in
reduction too long or takes too long to get to temp you get the washed out
pinkish or strawberry color as he calls it. He feels the oxyprobe is faulty
which I agree with especially at higher temps because I was certainly in to=
much reduction from the visible signs like the flame out the BOTTOM peep on
the Geil is where you read the flame length for reduction. I have tried to
get hold of Axner and am playing phone tag since no one answers the phone
when I call. I was told by an independent party that the gent who makes the
oxyprobes for Axner test them by "hitting it with a torch and if it gives a
reading it is calibrated" Save you thousand bucks these probes are USELESS.
Paul also said he finds if it is in reduction more than 3 hours the
reds start to go pink. I am going to refire the rest of the kiln load in
either a 3 hour reduction firing starting at 1700 or for this load in
oxidation to see what is salvageable. The reason I used to start reduction
at 1400 was it was the only time I got copper reds in the R Broadnax kiln
BUT when I turned the gas up on it, it flew up to a temp that melted the
kiln stilts and collapsed the shelves. So this was in reduction perhaps an
hour and a half so he may be on to something about too long a reduction
period. He also feels that even though the cones bent for ^6 that the heavy
reduction effected the glaze melt which from my refiring results mean it wa=
under mature. Just thought I would report back and I will refire the kiln
tomorrow and let everyone know. Thanks to everyone for your input...Liz