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fast firing update

updated tue 30 dec 97


Sylvia See on fri 4 apr 97

Hi Fraser,
Thanks for the update. I have been waiting for your results and the damn
spring to arrive here. I am using an old electric cone 10 7 cubic foot kiln
for raku and am interested in some reduction firing. I am surprised at the
speed of your firing, as I have been rakuing about this speed for my first
load. I find my 100 lb bottles of propane frost up on me if I use too much
pressure to fire it too fast but I am sure going to experiment with my
controls to see about opening it up some more. I have a 4" hole in the lid
of my kiln. Will this affect the ware close to the top of the kiln in a
reduction firing? I can use fiber and bricks to control the reduction by
blocking part of this hole. I have tested that and it works well. I have
gone as high as cone 7 and 8 so far, but I'm sure in the hot summer, where
my propane doesn't frost as easily I could get it to cone 10. Very
interesting. I also have my kiln set on wheels and can easily move it into
the garage after firing. Tipping pots is a concern though.
I would be interested in looking at your new program. I have been using
Insight for years and Tony has just upgraded it so am familiar with this
type of program. I really don't know what I would do without it. It's great
not having to shuffle through the stacks of paper looking for a recipe. Of
course, being a woman and a cook for a hundred years, I fall into the
category of testing an existing recipe once and then fixing it. Hee hee.
Not really. But I do take recipes that I like and adjusting them to cone 10
or backwards to cone 6. Also have done alot of experimenting trying to get
crystalline glaze effects, useful for functional pieces. However, I hate
having to grind of the bottoms as they run so bad. Results, have produced
some interesting glazes with special effects which I really liked, as I
wasn't hung up on the crystals as such.
Will watch for your postings and updates. Thanks for sharing your results
of reduction firings in Raku kiln.
Having fun in sunny Alberta through a driving snowstorm.
Sylvia See Claresholm Alberta
I really like my bifocals
My dentures fit me fine
My hearing aid works perfect
But Lord I miss my mind!!!!

Fay & Ralph Loewenthal on mon 7 apr 97

Sylvia See said: find my 100 lb bottles of propane frost up on me if I use
too much pressure to fire it too fast but I am sure going to experiment with my
controls to see about opening it up some more.

Sylvia if your bottles are freezing up then you should think of getting more
bottles joined together with a manifold. I found with my 10 cubic foot kiln I ha
four 48 Kgs (about 100Lbs) linked up with a manifold. I use two 4 Kgs (9 Lbs)
per hour burners. I do not know what that it is in BTU's, maybe one of the
fundis can give us that please. Anyway I never had a freeze up, even though I
should have had eight bottles - two 4 Kgs burners burn 8 Kgs gas per hour at
full blast, and the bottles give 1 Kg per hour.
Hope this helps from Ralph in a rather wintry PE SA

Fraser /Suzette on mon 29 dec 97

For anyone interested ... I have added a first update to my web page. I
have placed pictures of the base and top of the kiln in the building
stages. For the next week I will attempt to build this page so that
everyone can see how this kiln was built.
I was very interested in the thin shelf discussion. About a month ago I
replaced the shelves in my fiber kiln with thicker shelves and ever since
my firing time has been 1/2 to 1 hour longer. Last week (after reading some
of the posts) I put the original thinner shelves back in and the kiln is
firing as fast as before.
I am currently firing to a full cone 7 in just under 2 hours. I get great
reduction effects!

Anyone interested in gas reduction firing but don't want to spend 16 hours
per firing, thousands of dollars to invest in a kiln and don't throw
hundreds of pots at a time may be interested in this.

I will update the page as often as I have time.

Also the glaze calculation program I wrote Glaze Simulator is available for
win31 or win95. I have split the (very large) download file(s) into four
smaller download files. This should make downloading less frustrating.