Tom at Hutchtel.net on mon 1 aug 05
mostly)
> Thanks to RR, Bonnie and others - had a very successful firing today.
> Time
> was the culprit. I had been using my little Paragon A-77b and not much in
> it.
The key, besides time, is the loading factor. A kiln must have a fairly
full load to fire correctly. Heating the extra load is part of it, having
enough mass in the kiln to build radiation is the other. Above red heat,
most of the heat work going on in the kiln is from radiation, not from
convection from the elements. If you don't have enough ware, put a set of
posts, then a shelf, then stack your ware, and then some posts and shelves
to fill out to the top. This gets the work up in the kiln and adds mass to
the load.
Tom Wirt
Ron Roy on mon 1 aug 05
mostly)
Hi Carty,
When you are trying to find out how to slow down that kiln - you need to
know where it is firing hot - so have cones on different levels in the
kiln.
Lets say the middle is the hot spot - then slow down the kiln by turing the
middle switch to medium.
If the bottom is cold then maybe turn the top two switches to medium.
Remember also that soaking is very good for evening out a kiln.
RR
>Thanks to RR, Bonnie and others - had a very successful firing today. Time
>was the culprit. I had been using my little Paragon A-77b and not much in
>it. Firing was way too fast. I'm sure I will fully prove it out to myself
>over the next couple of weeks.
>
>BUT HERE IS MY ANSWER
>
>Yesterday (and last night) in the Skutt 1018 -
>about 16 pieces of pottery (some plates, small vase, cups bowls Standard 182
>and Standard 153 clay bodies...bisqued at Cone 04) RR White - Waterfall,
>Floating Blue - combos thereof -
>
>Both switches on low at 3:15 PM - both to medium at 4:30 PM - both to high
>at 6 PM.
>
>At 10:10 PM pyrometer said 2010 F.
>
>At 11:43PM the sitter tripped at 2190f and then (as can be found in Appendix
>E, p. 144 of MC6G) cone sitter overridden, both switches to medium and timer
>on kiln sitter set to four hours. Opened kiln at 7 tonight (was still 150F
>but couldn't wait any longer) and success! RR White was great - waterfall
>could have been a touch thicker on rims - but cup covered with waterfall did
>not drip to shelf, was nice dark brown with light rim - and FB was as usual
>great ( two dips was more interesting than one).
>
>I guess figuring out how to slow the Paragon A-77B down will be my final
>ticket to success (for small test runs - I'll try letting it go about 4 or 5
>hours on medium and then turn one switch to high leaving the other on
>medium- wonder how that will work getting to cone 6. But I see light at the
>end of the tunnel.
>
>Thanks all - fast firing can cause problems that appear to be other than
>what they are.
>
>Thanks.
>
>Carty Ellis
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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