Daphne Zeitz on fri 24 oct 97
Dear Vickki and Libby,
My decision to buy a "portable" propane kiln came about because the
building inspector in the municipality said, "we don't understand gas kilns
so we have decided not to allow them", when I inquired about installing a
"permanent" one. There was no changing his stand on the issue.
So I bought an Olympic propane kiln - about 10 cubic foot - which gave a lot
of problems to begin with, such as most of the flames shooting out of the
top of the kiln heating the great outdoors, hot top/cold bottom, cold
top/hot bottom, and uneven reduction.
Fortunately my husband is knowlegable about propane and got blank tips for
the burners and bored smaller orifices. It appeared that the tips the kiln
came with were for natural gas and the orifices were too large for propane.
Propane is a much drier, hotter burning gas and has more viscocity,
therefore to have it burn in the kiln, giving a nice even firing, smaller
orifices were required.
Subsequent experimentation with the shelf spacing and size, especialy the
one just before the vent hole has resulted in good consistent firing
results. I use a full shelf about 2" up from the bottom of the kiln and 1/2
shelves from there on up, with space for air movement between them - about
half an inch. The kiln came with a small shelf, about 12", to put just below
the vent but I have better results with a 16" one. The baffle is two kiln
bricks on the lid of the kiln, which are slid over the vent as required.
They don't last through many firings because of the great temperature
varients they are subjected to, but there are lots of uses for broken kiln
bricks in the raku kiln.
I have not done a lot with copper reds, although I have had some good test
results, but a friend has excellent copper reds with her Olympic propane
kiln, and didn't make any adjustments to it.
Any kiln is just an insulated box with a heat source, so don't be afraid to
experiment a bit with it.
Regards, Daphne
Daphne Zeitz
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