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a collection of pit firing responces, long.

updated fri 10 nov 00


Cat Audette on thu 9 nov 00

Date: Tue, 7 Nov 2000 15:00:58 -0000
From: Martin Howard
Subject: Re: Smoke/Pit/Dung firings

At the pit firing at Shotley for the EAPA (East Anglian Potters Association)
Summer Camp, had dug the hole during the previous year. This year we just
needed to open it up again and clear all growth around it, so as to reduce
the risk of fire spreading to the farmer's field next door.

In the bottom was screwed up paper and lots of wood, small them larger.
Leave space to fire the paper at the end.
Then the pots went in, sprinkled with glaze powder and lots of copper
wiring, odd fruit, banana skins etc. No dung was added, to my knowledge:-)
The whole was covered, over the middle part, with corrugated iron and fired.
The lie of the pit was along the prevalent wind direction.

Have a team on hand with a powerful water hose as the fire from the end
furthest from the direction of the wind gets pretty powerful.

Of course, you could add a pyrometer, just to add the modern touch.

Hope I haven't missed out anything, but others will add it if I have.

Martin Howard
Webb's Cottage Pottery
Woolpits Road, Great Saling

Date: Tue, 7 Nov 2000 10:27:37 -0800
From: Rick Brady
Subject: Re: Smoke/Pit/Dung firings

I burnish either directly with a stone on smaller pots or use terra sig and
burnish with a plastic bag on "larger" pots. Don't forget to wrap some pots
with copper wire (24ga) or wrap a pot with some fine #0000 steel wool. Pull
the steel wool apart and tie it on with some copper wire. Also, you might
try using a copper Chor-Boy scrubbing pad. Take it apart and then pull it
like a sock over a pot or tie it on with some copper wire. When it works it
can give stunning results. I mostly use a white cone 10 stoneware clay, but
you can use just about anything. I have had good results with B-Mix and
porcelain as well. I usually bisque to cone 09. In addition to Miracle
Grow, I use copper carb and rock salt in the pit over a bed of sawdust.

Good Luck!! Let me know if you have any other questions. I do a LOT of
pit firing and each firing can produce very unique results.

Rick Brady
Pleasanton, CA

>From: Automatic digest processor
>To: Recipients of CLAYART digests
>Subject: CLAYART Digest - 6 Nov 2000 to 7 Nov 2000 (#2000-175)
>Date: Wed, Nov 8, 2000, 12:00 am

> Date: Tue, 7 Nov 2000 08:01:25 -0700
> From: Marcia Selsor
> Subject: dung and sawdust
> Dear Cat,
> Sawdust:
> Use terra sig made with the infamous TSP
> Bisque at ^012-09
> You can put rock salt and copper carb in layers with sawdust sticks and
> newspaper in a can with a few holes in it. I use a can with 12 holes at
> four per level on an oil drum. Peipenburg starts the flame with a
> propane torch at the bottom. I have tried it this way and it works
> great. For additional coloring you can
> 1. color terra sig with mason stains
> 2. soak bisque pots in ferric chloride or copper chloride solution and
> keep your hands out of it and don't breathe fumes..
> 3. put some of the above in the sawdust next to pots.
> Make sure the lid is on and the fire is attended through the night-or
> that it is a safe place where a sudden wind won't blow cinders/embers
> anywhere causing a fire.
> DUNG Firing
> bisque 012-09 for keeping the burnished surface.
> 1. dig a hole about 18"-2 ' deep with a ledge about 1/2 way or more down
> that will hold a grate to sit the pots on.
> 2. start a fire on the bottom and let the coals build up. you can line
> the pots along the edge of the pit to dry them out and preheat.
> 3. when there is a good bed of coals, place the grate on the ledge. put
> pots on the grate upside down.
> 4. cover wih dung so the pile is a foot ot two above ground level.Lean
> metal sheets on top and sides. Maria Martinez used old license plates. I
> have used metal siding scraps
> 5. wait for the fire to ignite on the surface (sometime two or more
> hours of smoldering)
> 6. cover with ash when the fire is dying down. This helps blackness.
> (laing with a little horse dung helps with the blackness)
> Have fun,
> Marcia

Perfect timing, I just went to a lumber yard today to scrounge sawdust for a
pit firing. The pit is built of hard brick stacked on a sand base. You can
configure whatever size you need with the bricks and then use old kiln
shelves to cover it up.

I put saw dust in the bottom with a couple smaller pieces of wood and then
arrange my pieces on top of this. I sprinkle copper sulfate crystals,
from a hardware store as "Root Kill," and table salt around the pieces, on
top of the sawdust. Then fill in with more sawdust till the pieces are
covered by about 2". More copper sulfate and salt. Then loosely place
pieces of wood. Generous seasoning with lighter fluid and light. I keep
adding wood to get a good flame going and then maintain this for about 2
hours, sometimes I will add a bit more sawdust or more chemicals as the urge
strikes. Let the flames die out so you have glowing embers around the pots
and cover with the kiln shelves and allow the kiln gods to do their magic.
It all depends upon the firing how long it takes to finish firing out the
rest of the wood and sawdust and then cool enough to allow you to open it

All my surfaces are extremely smooth, burnished but not extremely shiny. I
have found that highly textured surfaces don't blend the best with the
vagaries of smoke firings. My best colorations have come from my hottest
firings. I have gotten pieces with lots of reds, grays, greens, yellows,
browns, whites, and aquas. You can also stain terra sig and brush that on
greenware before the bisque to add another dimension to the coloration.
Afterwards I wax with Min-Wax, a floor paste wax.

Once my students cooked a chicken wrapped first in tin foil and then in clay
in with the pots. It was delicious. Have fun.
Nora in Miami, hoping to get in a pit firing this coming weekend.

Hi Cat,

I have been using Standard #105 with grog for the sawdust pit firings I have
done. Sam at Clayworks Supplies recommended this clay body and I have gotten
good results. Most of the pots have been burnished and bisque at ^06 before
I pit fired them. I have also gotten good results using a slip made of
cobalt oxide which was applied and the burnished.

I have used sawdust and wood shavings. The sawdust must be very dry. If you
buy it in a plastic bag open it up and let the air get to it for a few days.
The plastic really seems to retain and moisture that was in the wood. A good
sawdust fire usually last 6-8 hours. When I have used shavings the fire was
quick, only a few hours and I got dramatic contrast of dark and light where
the clay body didn't take any of the smoke at all.

I have never used any oxides in the fire but have talked to people at MICA
who have used Miracle Grow in saggar fires with good results.

Hope this helps,
Wayne Bien