vince pitelka on mon 8 apr 02
> You folks always give such great info so I am writing to you for help. I
am
> involved in a workshop for older children this summer and I will be doing
the
> ceramics section. it will be in a remote location with no kilns. So I
need
> to be able to do a one time firing. I know the Native Americans used to
do
> this, how can I?
Kym -
I don't know where you are in the country or the world, but if you are in a
humid climate it is very difficult to bonfire your wares without a previous
bisque-fire. If you can at least heat the wares overnight in a 200 degree
Fahrenheit oven, you will drastically increase your success rate. If you
are in a dry climate you have less to worry about, but you still should
preheat the wares in an oven, and in either case you should apply the heat
VERY gradually in the bonfire. It will help greatly if the claybody has
LOTS of sand or grog in it - at least 25%. That "opens up" the claybody,
which allows water vapor to escape much more quickly, and it also makes the
claybody far more thermal-shock-resistant. If you are using commercial
bagged moist clay in 25-pound bags, just wedge 6 pounds of grog or sand into
each bag of clay.
Select a safe place for your bonfire, dig out a shallow pit (helps to
control the fire)and build up a crude grate of any kind of scrap iron
supported on bricks. Or best of all, have someone cut a 1-foot section off
one end of a 55-gallon drum, drill a lot of 1/2" holes in it, set that up on
bricks (the 1-foot section). In either case, pile the pots carefully on the
grate or in the drum, and then cover them with pot shards or scrap metal,
and build a very small fire underneath the grate/drum, keep it going for
several hours, and then SLOWLY increase the size of the fire over three or
four more hours until the fire pretty much encompasses the whole grate or
drum, and the steel is glowing red hot. At that point you can just let the
fire burn out if you want to retain the natural fired color of the clay or
slips, or if you want a blackware firing you can smother it with sawdust
and/or manure, and then bury it in dirt for at least three hours and then
dig it up (carefully!). Keep in mind that in a blackware firing you only
get jet black if you burnish the wares or use terra sig and polish the
wares. Otherwise you will just get an ugly flat charcoal grey on the bare
clay.
This is an exciting process, and the kids will love it, especially if the
pots come out intact!
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Kym Valvieja on mon 8 apr 02
Dear Clayarters,
You folks always give such great info so I am writing to you for help. I am
involved in a workshop for older children this summer and I will be doing the
ceramics section. it will be in a remote location with no kilns. So I need
to be able to do a one time firing. I know the Native Americans used to do
this, how can I? Thanking you in advance.
Sincerely,
Kym Valvieja
P.S. Is it true than misting with vinegar prior to firing in the pit will
make it stronger?
Ed Kraft on tue 9 apr 02
Vince,
I know that you are the expert in primitive firing. So I'm Just offering my
limited observation.
Last weekend the wife and I went camping by the water here in the vary humid
Pacific Northwest. I always bring a little clay along to make impressions.
No grog or sand in this cone six clay body. After making a few things we
dried them slowly by the camp fire. After the evening fire I spread out the
coals and placed the items around the edge so they would be fully dry by
morning. In the morning I placed the pieces directly on the still warm/hot
coals. I split kindling size wood and built the fire directly over the
warm/hot pots. In 30 min. you could see the pots glowing red. I removed them
with sticks and buried them in organic matter gleaned from the forest floor.
They all survived except for one that chipped off a couple of pieces where
it had been placed on the hot part of the coals. The blackened ware came
fine showing the shine from the crude burnishing done by smooth driftwood
stick.
They may not be marketable but much fun was had by both. Ed
P.S. Take Vinces advice
Earth Arrangements
2109 39th St
Bellingham, WA 98226
360 734- 6839
eartharr@msn.com
www.eartharrangements.com
----- Original Message -----
From: "vince pitelka"
To:
Sent: Monday, April 08, 2002 7:29 PM
Subject: Re: Pitfiring, I need help!
> > You folks always give such great info so I am writing to you for help.
I
> am
> > involved in a workshop for older children this summer and I will be
doing
> the
> > ceramics section. it will be in a remote location with no kilns. So I
> need
> > to be able to do a one time firing. I know the Native Americans used to
> do
> > this, how can I?
>
> Kym -
> I don't know where you are in the country or the world, but if you are in
a
> humid climate it is very difficult to bonfire your wares without a
previous
> bisque-fire. If you can at least heat the wares overnight in a 200 degree
> Fahrenheit oven, you will drastically increase your success rate. If you
> are in a dry climate you have less to worry about, but you still should
> preheat the wares in an oven, and in either case you should apply the heat
> VERY gradually in the bonfire. It will help greatly if the claybody has
> LOTS of sand or grog in it - at least 25%. That "opens up" the claybody,
> which allows water vapor to escape much more quickly, and it also makes
the
> claybody far more thermal-shock-resistant. If you are using commercial
> bagged moist clay in 25-pound bags, just wedge 6 pounds of grog or sand
into
> each bag of clay.
>
> Select a safe place for your bonfire, dig out a shallow pit (helps to
> control the fire)and build up a crude grate of any kind of scrap iron
> supported on bricks. Or best of all, have someone cut a 1-foot section
off
> one end of a 55-gallon drum, drill a lot of 1/2" holes in it, set that up
on
> bricks (the 1-foot section). In either case, pile the pots carefully on
the
> grate or in the drum, and then cover them with pot shards or scrap metal,
> and build a very small fire underneath the grate/drum, keep it going for
> several hours, and then SLOWLY increase the size of the fire over three
or
> four more hours until the fire pretty much encompasses the whole grate or
> drum, and the steel is glowing red hot. At that point you can just let
the
> fire burn out if you want to retain the natural fired color of the clay or
> slips, or if you want a blackware firing you can smother it with sawdust
> and/or manure, and then bury it in dirt for at least three hours and then
> dig it up (carefully!). Keep in mind that in a blackware firing you only
> get jet black if you burnish the wares or use terra sig and polish the
> wares. Otherwise you will just get an ugly flat charcoal grey on the bare
> clay.
>
> This is an exciting process, and the kids will love it, especially if the
> pots come out intact!
> Best wishes -
> - Vince
>
> Vince Pitelka
> Appalachian Center for Crafts
> Tennessee Technological University
> 1560 Craft Center Drive, Smithville TN 37166
> Home - vpitelka@dtccom.net
> 615/597-5376
> Work - wpitelka@tntech.edu
> 615/597-6801 ext. 111, fax 615/597-6803
> http://www.craftcenter.tntech.edu/
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
Roger Korn on tue 9 apr 02
vince pitelka wrote:
> ... Or best of all, have someone cut a 1-foot section off
> one end of a 55-gallon drum, drill a lot of 1/2" holes in it, set that up on
> bricks (the 1-foot section). In either case, pile the pots carefully on the
> grate or in the drum, and then cover them with pot shards or scrap metal,
> ...
Even better than my "holey ceramic saggar" idea, because you don't have to rebuild
the saggar for each firing.
> This is an exciting process, and the kids will love it, especially if the
> pots come out intact!
It's been a great "kid magnet" in Camp Verde. All of a sudden the kids don't have
to be soooo cool, and they just want to play with clay.
Roger
>
> Best wishes -
> - Vince
>
> Vince Pitelka
> Appalachian Center for Crafts
> Tennessee Technological University
> 1560 Craft Center Drive, Smithville TN 37166
> Home - vpitelka@dtccom.net
> 615/597-5376
> Work - wpitelka@tntech.edu
> 615/597-6801 ext. 111, fax 615/597-6803
> http://www.craftcenter.tntech.edu/
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.
--
Roger Korn
McKay Creek Ceramics
In AZ: PO Box 463
4215 Culpepper Ranch Rd
Rimrock, AZ 86335
928-567-5699 <-
In OR: PO Box 436
31330 NW Pacific Ave.
North Plains, OR 97133
503-647-5464
Kym Valvieja on tue 9 apr 02
Wow Vince thank you so much for the info. As a matter of fact this workshop
will be in Hawaii on the big Island of Hawaii. This is a camp for at risk
teenagers to instill the Hawaiian values and learn to work together amongst
themselves and with the elders of the program.
Should I use sculpture clay? I believe Laguna has a buff sculpture clay goes
to about ^5 or 6, would that be good? Also this project will be masks so
they will be smaller with a slight curve. Can I dig the pit on the beach in
the sand or should I go farther back in the dirt? I'm sure they have an oven
there so I should be able to heat the masks over night as you suggest. We
will not be burnishing so what kind of terra sig would you suggest to get the
blackest black? And what would seaweed do? I have pitfired bisqued pieces
with beautiful results. Would I get any red flashing with unbisqued pieces?
I can't thank you enough for your info. I am an older student returning to
school for my BFA from University of Southern California, where I am a full
time junior plugging away. This is such a great opportunity for me I want
everything to be fabulous for these kids. Thanks again!
Sincerely,
Kym Valvieja
Snail Scott on tue 9 apr 02
At 11:07 AM 4/8/02 EDT, you wrote:
>...it will be in a remote location with no kilns. So I need
>to be able to do a one time firing. I know the Native Americans used to do
>this, how can I?
If there is an oven for cooking, pre-heat the work before
firing; this will really improve your (non)breakage rate.
This can help regardless of which kilnless-firing style
you end up pursuing.
-Snail
vince pitelka on tue 9 apr 02
I am including this entire message in my reply, because I wanted to make
sure everyone interested in pitfiring read this. What a wonderful thing to
do. Ed, you are to be commended. I think the secret is in the slow
heat-up. I may be overly cautious in my approach, but when I have a bunch
of participants at a five-day workshop, I would prefer not to destroy a
single piece. But doing this in two days out on the beach sounds wonderful.
- Vince
Ed Kraft wrote:
> Last weekend the wife and I went camping by the water here in the vary
humid
> Pacific Northwest. I always bring a little clay along to make impressions.
> No grog or sand in this cone six clay body. After making a few things we
> dried them slowly by the camp fire. After the evening fire I spread out
the
> coals and placed the items around the edge so they would be fully dry by
> morning. In the morning I placed the pieces directly on the still warm/hot
> coals. I split kindling size wood and built the fire directly over the
> warm/hot pots. In 30 min. you could see the pots glowing red. I removed
them
> with sticks and buried them in organic matter gleaned from the forest
floor.
> They all survived except for one that chipped off a couple of pieces where
> it had been placed on the hot part of the coals. The blackened ware came
> fine showing the shine from the crude burnishing done by smooth driftwood
> stick.
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Michele Williams on wed 10 apr 02
Here in Miami, Florida, the ultimate in hot, humid environments (humidity is
sometimes 90+%), our ceramics classes all do one or more pit firings. There
is a 3 x 3 pit dug into the ground, some bricks that line the softer walls.
Since we have coral here, this required a pick axe to dig more than 3" deep.
As far as I know, the profs have never pre-heated anything. We carry the
greenware in our hands from the air-conditioned classroom where the drying
racks are and put it somewhere in the pile of sawdust, lumber, wood pieces,
seaweed, garbage, etc. that we have gathered, adding chemicals such as
copper or other colorants where somebody wants them. When the hole is full,
we add the matches. It burns for about 90 minutes at full blast, then we
put a sheet of tin on to cover on it. Three days later, we go out and get
our stuff and all its surprises.
We have little breakage if we are careful to note what is fragile, what is
going to be over something that will burn away and fall into the coals, etc.
Humidity has not been a factor here. However, due to the dampening effect
rain can have on our flammable materials, we do not pit fire on rainy days!
Have fun!
Michele Williams
vince pitelka on wed 10 apr 02
> Should I use sculpture clay? I believe Laguna has a buff sculpture clay
goes
> to about ^5 or 6, would that be good?
Kim -
You want to find the clay with the largest sand or grog content, and as I
suggested in the previous message, you should wedge additional sand or grog
into the clay so it contains a total of 30 to 50%.
> Can I dig the pit on the beach in
> the sand or should I go farther back in the dirt? I'm sure they have an
oven
> there so I should be able to heat the masks over night as you suggest.
You can dig the pit anywhere it is safe regarding the fire, so out on the
sand would be ideal.
> will not be burnishing so what kind of terra sig would you suggest to get
the
> blackest black?
You can make your terra sig from Redart or from any ball clay and you should
get a good black. The ball clay slip, although it looks pure white after
the bisque firing, actually takes more carbon and gives a richer black in a
blackware firing. But I like the variations between red-brown and black
that you get with a Redart terra sig.
> And what would seaweed do?
Some people use seaweed when they pitfire bisque-fired pots with chemicals
and other combustibles, but that is a completely different process. I
really do not know if seaweed would do anything in this kind of bonfiring.
> Would I get any red flashing with unbisqued pieces?
I don't know. You'll find out though, so please report back to us.
Good luck and have a great time -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
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