Christine Laginess on sun 14 feb 99
Hi to everyone
I undertook a saggar firing last year and was not happy with my results. Let
me tell you what I did and the results, before I ask my questions.
I used a new garbage can and put about 3 inches of sawdust in the bottom. I
used terra sig. and burnished the surface of my piece. I then wrapped it in
copper wire and put it in the garbage can saggar. In with the piece I put
copper carbonate and kosher salt. I placed the lid on the garbage can and
fired it in our raku kiln. I took about 4 hours to bring it to about 1800 F.
Waited a couple of days to open it, hoping for rave reviews. But much to my
surprise it was totally black. No beautiful flashes of orange or red, no
interesting patterns, just black. What did I do wrong. This was not the
effect I had hoped for. It wasn't awful, just not what I expected.
I got the information on saggar firing out of Clay Times and followed the idea
of a fellow student in using the garbage can saggar. His were great. Mine
were not. I asked my instructor and he said that perhaps the can lid was to
tight and therefore I had had reduction. But actually I thought the lid was
suppose to be somewhat air tight. Am I wrong in this. It seems that in all I
have read, the instructions tell you to have an airtight situation. In the
Clay Times article they were filling all the holes and when i read about
saggars they mention tight fitting lids.
If anyone out there can help me with this I would greatly appreciate it.
Saggar firing is beautiful and I don't want to give up on it. I am sure that
I am just misunderstanding some point about it.
Thanks again,
Christine
Vince Pitelka on mon 15 feb 99
>I used a new garbage can and put about 3 inches of sawdust in the bottom. I
>used terra sig. and burnished the surface of my piece. I then wrapped it in
>copper wire and put it in the garbage can saggar. In with the piece I put
>copper carbonate and kosher salt. I placed the lid on the garbage can and
>fired it in our raku kiln. I took about 4 hours to bring it to about 1800 F.
>Waited a couple of days to open it, hoping for rave reviews. But much to my
>surprise it was totally black. No beautiful flashes of orange or red, no
>interesting patterns, just black. What did I do wrong. This was not the
>effect I had hoped for. It wasn't awful, just not what I expected.
Christine -
First we need to clarify the terminology. This is not a sagger firing. It
is a sawdust smoking, which is not a true firing process at all. It never
reaches true firing temperatures, and the primary effects you get in this
process come from smoke and creosote. A sagger firing requires a refractory
container placed inside a regular kiln, with the wares placed within the
refractory container along with various combustibles and other materials, as
you mention above. You cannot expect copper carbonate and sea salt to do
much in a sawdust smoking.
And a sawdust smoking will not work at all with an airtight lid. Air must
be passing through the chamber to keep the sawdust burning. In contrast, a
true sagger within a kiln must be tightly sealed to keep the chemical
effects inside the sagger.
Good luck -
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Rob on tue 16 feb 99
I have used clay flower pots that are just a little bigger than the pot. Put
maybe 2 handfuls of sawdust or shavings in the bottom, about 2+ tbls of sea, roc
or kosher salt in the bottom. sprinkle some copper sulfate, maybe 1 tbls around
the bottom (You can set the piece right side up or upside down) some copper wire
or bronze wool (from a hardware store, paint dept.) and fire as you did. The
lids are not air tight. They are either another flower pot on top (plugging the
bottom holes) or a piece of broken kiln shelf on top. I think the better the
seal the more the gasses and fumes are able to interact with the pot, but those
burning, expanding gasses will find a way out of the saggar. With this I've
gotten white (with burnished porcelain), black, browns and pinks. Adding more
burnable material may be giving you the heavy black, although this can also be
nice. I haven't noticed any difference with cat food, banana peels or the myria
of other combustibles that some folks use.
Robert Craig
Christine Laginess wrote:
> ----------------------------Original message----------------------------
> Hi to everyone
>
> I undertook a saggar firing last year and was not happy with my results. Let
> me tell you what I did and the results, before I ask my questions.
>
> I used a new garbage can and put about 3 inches of sawdust in the bottom. I
> used terra sig. and burnished the surface of my piece. I then wrapped it in
> copper wire and put it in the garbage can saggar. In with the piece I put
> copper carbonate and kosher salt. I placed the lid on the garbage can and
> fired it in our raku kiln. I took about 4 hours to bring it to about 1800 F.
> Waited a couple of days to open it, hoping for rave reviews. But much to my
> surprise it was totally black. No beautiful flashes of orange or red, no
> interesting patterns, just black. What did I do wrong. This was not the
> effect I had hoped for. It wasn't awful, just not what I expected.
>
> I got the information on saggar firing out of Clay Times and followed the idea
> of a fellow student in using the garbage can saggar. His were great. Mine
> were not. I asked my instructor and he said that perhaps the can lid was to
> tight and therefore I had had reduction. But actually I thought the lid was
> suppose to be somewhat air tight. Am I wrong in this. It seems that in all I
> have read, the instructions tell you to have an airtight situation. In the
> Clay Times article they were filling all the holes and when i read about
> saggars they mention tight fitting lids.
>
> If anyone out there can help me with this I would greatly appreciate it.
> Saggar firing is beautiful and I don't want to give up on it. I am sure that
> I am just misunderstanding some point about it.
>
> Thanks again,
> Christine
Vince Pitelka on wed 17 feb 99
>>I used a new garbage can and put about 3 inches of sawdust in the bottom. I
>>used terra sig. and burnished the surface of my piece. I then wrapped it in
>>copper wire and put it in the garbage can saggar. In with the piece I put
>>copper carbonate and kosher salt. I placed the lid on the garbage can and
>>fired it in our raku kiln. I took about 4 hours to bring it to about 1800 F.
>>Waited a couple of days to open it, hoping for rave reviews. But much to my
>>surprise it was totally black. No beautiful flashes of orange or red, no
>>interesting patterns, just black. What did I do wrong. This was not the
>>effect I had hoped for. It wasn't awful, just not what I expected.
Christine -
I have to appologize for jumping the gun on this one. It was the trash can
that confused me. When I went back and read your message again the
following day I realized I had made a mistake. What you did WAS a sagger
firing, but I have never heard of anyone doing sagger firing inside a metal
garbage can inside a kiln. My guess would be that since the garbage can
took up so much of the kiln space, the area around the garbage can got up to
1800 F fairly quickly (and 4 hours would be considered pretty quick), and
the inside of the garbage can got nowhere near this temperature. A sagger
that large needs a long slow firing to come up to temperature, depending on
how tightly it is packed.
Sorry for the misunderstanding -
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Barbara Lewis on thu 18 feb 99
Christine: I usually fire between 7 and 8 hours. Try it again and fire it
slower. Should work. Be careful with the amount of sawdust you use. If
you use too much it can obliterate any color you might achieve. I would
reduce the sawdust -- 3 inches seems like a lot. Reduce to maybe half that
amount. Good luck and let us know. Barbara
At 09:19 AM 2/17/99 EST, you wrote:
>----------------------------Original message----------------------------
>>>I used a new garbage can and put about 3 inches of sawdust in the bottom. I
>>>used terra sig. and burnished the surface of my piece. I then wrapped it in
>>>copper wire and put it in the garbage can saggar. In with the piece I put
>>>copper carbonate and kosher salt. I placed the lid on the garbage can and
>>>fired it in our raku kiln. I took about 4 hours to bring it to about 1800 F.
>>>Waited a couple of days to open it, hoping for rave reviews. But much to my
>>>surprise it was totally black. No beautiful flashes of orange or red, no
>>>interesting patterns, just black. What did I do wrong. This was not the
>>>effect I had hoped for. It wasn't awful, just not what I expected.
>
>Christine -
>I have to appologize for jumping the gun on this one. It was the trash can
>that confused me. When I went back and read your message again the
>following day I realized I had made a mistake. What you did WAS a sagger
>firing, but I have never heard of anyone doing sagger firing inside a metal
>garbage can inside a kiln. My guess would be that since the garbage can
>took up so much of the kiln space, the area around the garbage can got up to
>1800 F fairly quickly (and 4 hours would be considered pretty quick), and
>the inside of the garbage can got nowhere near this temperature. A sagger
>that large needs a long slow firing to come up to temperature, depending on
>how tightly it is packed.
>Sorry for the misunderstanding -
>- Vince
>
>Vince Pitelka - vpitelka@DeKalb.net
>Home 615/597-5376, work 615/597-6801, fax 615/597-6803
>Appalachian Center for Crafts
>Tennessee Technological University
>1560 Craft Center Drive, Smithville TN 37166
>
Wellspring Clayworks
5412 Well Spring Road
La Plata, MD 20646
blewis@crosslink.net
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