Ron Roy on sun 18 nov 01
This subject is an excellent opportunity for some experimentation - wish I
had the time but no way these days.
What is needed.
A working pyrometer - calibrated with pyrometric cones for top temperature
- or a controller - calibrated the same way.
A kiln loaded with shelves and posts to simulate a standard load - which
will depend on the size if the kiln. This can be determined by weighing the
pots, shelves and posts from a normal firing and duplicating that weight
with just shelves and posts.
A kiln with 3 switches with high, medium and low settings.
After temperature is reached - but keeping the kiln turned on - start by
turning individual switches down for each firing as follows.
Control firing - the actual rates of cooling temperature (all switches off
at top temp) of a typical firing the one you base the weight of ware and
shelves for the experimental firings.
#1 All switches down to medium.
#2 All switches turned down to low
#3 If kiln fires cooler on bottom - bottom switch on medium - top two on low
#4 If Kiln normally is cooler at top - bottom two switches on low - top on
medium.
There are other combinations one on high two on medium, one on high two on
low but perhaps not necessary - WARNING - the kiln must be monitored
carefully at the start of the cool down to make sure it is actually
cooling. Best to have two witness cone packs visible with a higher guard
cone to make sure heat is not increasing in different parts of the kiln.
As each test firing cools - the indicated temperature should be noted -
lets say every half hour down to 700C (1300F) - best to use a timer and
stay with the kiln - or take the timer with you. - if you leave the room.
Anyone willing to do this - feel free to contact me directly if I have not
included information you need. This kind of information would be an
excellent basis for an article for potters.
Information on type of kiln, size, amount of insulation and age of kiln
will make the information more useful.
I would also think that having a series of glazes - on test tiles - same
glazes - different firings - would make these experiments sensational.
RR
>I wrote:
>>>...when the ^6 is at '9-oclock'
>>>I turn all the switches to 'low' and set the timer for
>>>three hours.)
>
>At 12:25 AM 11/14/01 -0400, Ron wrote:
>>Any chance you know what the drop in temp is over the two hour Snail.
>
>
>No clue. Don't own a pyrometer. Seems to make
>the matte glazes look good, though.
> -Snail
Ron Roy
RR# 4
15084 Little Lake Rd..
Brighton,
Ontario, Canada
KOK 1H0
Residence 613-475-9544
Studio 613-475-3715
Fax 613-475-3513
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