O'Hara, Kevin P. on tue 11 mar 97
Hello all,
Work has been rather busy lately so I haven't been able to keep up with
everything.
I finally was able to experiment with Pit/Bon firing.
I fired 2 unfired pots. One was a jar made from some recycled clay and the
other was a jar made from clay that was straight from the bag. I did not
fire in a pit but on top the ground. I gathered up a pile of leaves,
sticks, dead weeds & wood chips and surrounded my 2 pots in the stuff. I
them started a fire on top of the pile with small dry sticks and then larger
dry branches. The fire got hot rather quickly and one of my pots (the one
from recycled clay) began sounding like popcorn. I went ahead and burned
the pile of brush because I had to get rid of it anyway. After the fire had
burned down I noticed that the pot that was made from clay straight from the
bag was intact except for a small hole blown in the side and part of the
base cracked and blown away from the bottom. The thickness of the pots were
even and about a 1/4 inch or less. The bottom may have been a tiny bit more
than a quarter inch. So, if you turn the pot around to one side, it looks
fine. I texture the surface and I really like the smoky effects and the
brush gave to the surface, but I was rather disappointed with the
explosions.
I wanted to see if I could fire the greenware in this type of a firing. I
saw that I could reach a temperature that would cause the chemical reaction
in the clay, but I found it very difficult to control the temperature of the
fire. I suppose it is easier to get the smoky effects by bisque firing
first, but isn't there just as much risk of getting too hot too fast? I was
thinking that some moisture from the brush may have absorbed into the
greenware? I was also thinking of pre-heating a pot in the oven before
starting a fire on top of it? I have another idea of digging a small
pit/chamber in the side of a hill and digging a firing chamber underneath,
kind of like a small earthen-wood kiln? I don't know if that would work or
not? I think it's just the pyro in me that is trying to be creative.
I keep hearing people talking about using sawdust. wouldn't that cause
uneven heating if the fire started on one side of the pot and migrated to
the other side in the early stages of the firing?
Any suggestions would be appreciated.
Have a good day !
Thanks
Kevin P. O'Hara
ohara@indy.cp.lucent.com
mudslinger@iquest.net
www.iquest.net/~mudslinger
Oh, by the way, my new web site is about a week or two old. Stop in a take
a look :-)
Marcia Selsor on wed 12 mar 97
It has been my experience when firing raw pots in this way, to preheat
them as you prepare the coals. I have used a pit. Start the fire,
build up coals with the pots around the edge preheating. Then place a
grill over the coals, place the pots on the grill, covers with whatever
(cow dung in my case) and let it smolder until all combustibles are
spent.
Good luck.
Marcia in Montana where cow dung is plentiful
O'Hara, Kevin P. wrote:
>
> ----------------------------Original message----------------------------
> Hello all,
> Work has been rather busy lately so I haven't been able to keep up with
> everything.
> I finally was able to experiment with Pit/Bon firing.
> I fired 2 unfired pots. One was a jar made from some recycled clay and the
> other was a jar made from clay that was straight from the bag. I did not
> fire in a pit but on top the ground. I gathered up a pile of leaves,
> sticks, dead weeds & wood chips and surrounded my 2 pots in the stuff. I
> them started a fire on top of the pile with small dry sticks and then larger
> dry branches. The fire got hot rather quickly and one of my pots (the one
> from recycled clay) began sounding like popcorn. I went ahead and burned
> the pile of brush because I had to get rid of it anyway. After the fire had
> burned down I noticed that the pot that was made from clay straight from the
> bag was intact except for a small hole blown in the side and part of the
> base cracked and blown away from the bottom. The thickness of the pots were
> even and about a 1/4 inch or less. The bottom may have been a tiny bit more
> than a quarter inch. So, if you turn the pot around to one side, it looks
> fine. I texture the surface and I really like the smoky effects and the
> brush gave to the surface, but I was rather disappointed with the
> explosions.
>
> I wanted to see if I could fire the greenware in this type of a firing. I
> saw that I could reach a temperature that would cause the chemical reaction
> in the clay, but I found it very difficult to control the temperature of the
> fire. I suppose it is easier to get the smoky effects by bisque firing
> first, but isn't there just as much risk of getting too hot too fast? I was
> thinking that some moisture from the brush may have absorbed into the
> greenware? I was also thinking of pre-heating a pot in the oven before
> starting a fire on top of it? I have another idea of digging a small
> pit/chamber in the side of a hill and digging a firing chamber underneath,
> kind of like a small earthen-wood kiln? I don't know if that would work or
> not? I think it's just the pyro in me that is trying to be creative.
>
> I keep hearing people talking about using sawdust. wouldn't that cause
> uneven heating if the fire started on one side of the pot and migrated to
> the other side in the early stages of the firing?
>
> Any suggestions would be appreciated.
>
> Have a good day !
>
> Thanks
> Kevin P. O'Hara
> ohara@indy.cp.lucent.com
> mudslinger@iquest.net
> www.iquest.net/~mudslinger
>
> Oh, by the way, my new web site is about a week or two old. Stop in a take
> a look :-)
--
Marcia Selsor
http://www.imt.net/~mjbmls/
mjbmls@imt.net
Roger King on wed 12 mar 97
Kevin,
I have done many of the same type of firings myself, and found that no
matter how dry the greenware ( one piece I fired was dried for over a
year!) it will still easily experience blowouts. The solution is a very
low, slow bisque firing, to about cone 010. Then use foil and tins to
cover the pots during the first stage of pit firing to insulate and
distribute the heat, the weeds and brush that is burning on top of the
tins, pots below. Once the fire is built up for about forty minutes,
remove the tins and light the rest of the fire, proceeding normally with
minimal problems.
Hope this helps out.
Kevin
O'Hara, Kevin P. wrote:
>
> ----------------------------Original message----------------------------
> Hello all,
> Work has been rather busy lately so I haven't been able to keep up with
> everything.
> I finally was able to experiment with Pit/Bon firing.
> I fired 2 unfired pots. One was a jar made from some recycled clay and the
> other was a jar made from clay that was straight from the bag. I did not
> fire in a pit but on top the ground. I gathered up a pile of leaves,
> sticks, dead weeds & wood chips and surrounded my 2 pots in the stuff. I
> them started a fire on top of the pile with small dry sticks and then larger
> dry branches. The fire got hot rather quickly and one of my pots (the one
> from recycled clay) began sounding like popcorn. I went ahead and burned
> the pile of brush because I had to get rid of it anyway. After the fire had
> burned down I noticed that the pot that was made from clay straight from the
> bag was intact except for a small hole blown in the side and part of the
> base cracked and blown away from the bottom. The thickness of the pots were
> even and about a 1/4 inch or less. The bottom may have been a tiny bit more
> than a quarter inch. So, if you turn the pot around to one side, it looks
> fine. I texture the surface and I really like the smoky effects and the
> brush gave to the surface, but I was rather disappointed with the
> explosions.
>
> I wanted to see if I could fire the greenware in this type of a firing. I
> saw that I could reach a temperature that would cause the chemical reaction
> in the clay, but I found it very difficult to control the temperature of the
> fire. I suppose it is easier to get the smoky effects by bisque firing
> first, but isn't there just as much risk of getting too hot too fast? I was
> thinking that some moisture from the brush may have absorbed into the
> greenware? I was also thinking of pre-heating a pot in the oven before
> starting a fire on top of it? I have another idea of digging a small
> pit/chamber in the side of a hill and digging a firing chamber underneath,
> kind of like a small earthen-wood kiln? I don't know if that would work or
> not? I think it's just the pyro in me that is trying to be creative.
>
> I keep hearing people talking about using sawdust. wouldn't that cause
> uneven heating if the fire started on one side of the pot and migrated to
> the other side in the early stages of the firing?
>
> Any suggestions would be appreciated.
>
> Have a good day !
>
> Thanks
> Kevin P. O'Hara
> ohara@indy.cp.lucent.com
> mudslinger@iquest.net
> www.iquest.net/~mudslinger
>
> Oh, by the way, my new web site is about a week or two old. Stop in a take
> a look :-)
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