Philip Poburka on wed 31 jan 01
You could allways add a little 'thermite'...or soak 'sawdust' in any of a
variety of 'per-oxides' with some benign hydrocarbons, as 'marshmallow' or
That would help it 'climb' the Thermometer some.
Uhhhh...just kidding!..sort of...
It would 'bring-it-up'...maybe a little fast!
But 'could be done'!
Maybe there is a Chemist here to offer further elucidation?
I should think Cone 10, 12, 14 even...be 'no-problem'...just the
'thermal-shock' would be...a 'problem'!
It would get 'er plenty 'HOT'...
From: Logan Oplinger
Sent: January 30, 2001 5:57:45 AM GMT
Subject: (Long)Re: not so handy womwan's kiln
I will have to disagree to some extent with what you say about "garbage can
---- you wrote:
>...The wares are bedded in
> sawdust, which is ignited from the top and smolders down through over
> hours or so (ideally). But the sawdust smoking process never reaches even
> minimal sintering temperatures, and the wares must be bisque-fired first.
I use a scaled down version, making a firing container out of a large coffee
can (6"d x7"h). The sawdust I use is coarse (> 1/16") with most of the
fines (< 1/16") removed by screening out. In testing, both earthenware and
stoneware clays were fired to very low red heat (pulled & observed during
test firing, near end of firing). The size of the pieces were beads no more
than 3/8" thick and 1.5" long. Soaking the beads in water several hours
after firing did not produce any deterioration.
The coffee can has the bottom removed & saved. A square piece of 1/8" wire
mesh is attached to the bottom w/ four pieces of bailing wire. The bailing
wire is wrapped around the can rim and the wire mesh. The container is set
on 3 small rocks inside a barbecue pit or other suitable outdoor location
where nothing will catch fire. To load, sawdust is placed in the coffee can
up to the first ring, and a layer of beads place on the sawdust at 1/2"
spacing. The loading is continued the same for each ring. The last layer
of sawdust to the top of the can has no beads placed on top.
To light, the TOP SURFACE ONLY of the sawdust is wetted with charcoal
lighter fluid, and ignited. Flames are allowed to burn out, and a piece of
aluminum window screen is placed over the top of the can to prevent sparks
from flying out. If there is a breeze blowing, the saved bottom of the
coffee can is is used as a damper by placing it over the top of the can to
control the rate of burn. The whole firing process is somewhat variable
taking about four hours, depending upon packing, type of sawdust, and air
The coffee can process described may be reaching a higher temperature
because air may have better access to the sawdust to produce more efficient
combustion. A fine sawdust does not burn as well as the coarse, and
produces beads with more carbon coloring.
Submitted for comment.
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