Naomi Rieder on wed 22 sep 99
Dear Clayarters:
Does anyone have any idea why a pit-firing re-oxidizes? That's what just
happened. The only reduction was on surfaces buried in sawdust, or in pots
filled with sawdust. No flashing--used only copper carb & soda ash, lots of
hardwood sawdust, lots of hardwood--nothing broke, but practically nothing
happened as far as color, markings, that I've gotten in a real pit.
Please note that this "pit" was not in the ground, but rather a surface brick
structure, with inside dimensions of 4'w x 5'l x 39"h. This is the second
firing in this "thing". The first one resulted in almost everything
breaking, but the colors were great. The consensus was that there wasn't
enough wood, and the fire went too fast. This time, the pots were covered
with sawdust, then about 4-5" of hardwood very closely placed, a layer of
sawdust, then wood, criss-crossed, almost up to the top. Left uncovered to
burn for about 1-1/2 hours, when one half seemed to be dying down, so added
more wood, then, after the flames got below the edge of the walls, covered
the inside with a blanket of 1" ceramic fibre, then the corrugated steel
sheets. Plugged gaps in bricks and under the steel sheets. The "pit" was
too hot to empty the next morning, so didn't get to empty it until the 2nd
day after the firing.
I know I did something wrong, but I don't know what.
Much, Much thanks for your help.
Naomi
L.P. Skeen on thu 23 sep 99
Naomi Rieder wrote:
> ----------------------------Original message----------------------------
> Dear Clayarters:
>
> Does anyone have any idea why a pit-firing re-oxidizes? That's what just
> happened. The only reduction was on surfaces buried in sawdust, or in pots
> filled with sawdust. No flashing--used only copper carb & soda ash,
Naomi,
Ok, I'll bite. Why are you putting Soda Ash in the pit kiln?
Next, I'll ask about the kiln: Are you using fire brick, insulation brick, or
house brick? My experience w/ house brick (see my webpage for pics) has been
that after about the 2nd firing you just have to replace the bricks, because the
get broken down so badly that too much air gets into the kiln no matter what you
do to stop it. Also, the broken pieces tend to fall GUESS WHERE? and that's no
fun atall.
'nother question: Are you spraying your pots w/ the copper, or just sprinkling
it around? That makes a big ol' difference. I think next time I'm gonna try
just dunking one in a bowl of copper sulfate and let dry 2 days, then pit fire.
That sucker oughta be RED!!!
Good luck.
--
Lisa Skeen ICQ#15554910
http://www.living-tree.net
Living Tree Pottery & Soaps, Summerfield, NC
~*~* A clean house is a sign of a misspent life.*~*~
@}~~~ Religions should get out of politics or be taxed.~~~{@
Karen Broderick on thu 23 sep 99
If you pick up Robert Piepenburg's book
Spirit of Clay there is word for word detail
on how to do a pit firing and we get good
results at school when we follow them ....... good luck
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