[Jennifer Harnetty]

In the Ceramic Arts Daily blog today, I posted a recent article from Ceramics Monthly on the efforts of several university ceramics programs to reduce their environmental impact. I thought I would try to continue the discussion here. So, read the article and then share your thoughts. Will these practices work for the average studio potter? What are you doing to make your studio practice more green?

[denise]

I read this article in one of the recent issues of ceramics monthly. I was intrigued by the idea of recycling since our studio generates a lot of clay slop and glaze. We usually reclaim the clay slop, but we have been amassing the glaze slop for 3 years now. I don't want to throw it away because I don't want to contaminate our drinking water For a while we were using it as a pot luck glaze, but it was just an ugly black color.

After reading the article several weeks ago I wanted to try my hand at it. But instead of bricks I wanted to make flower pots. My plan was to take the glaze and clay slurry mix and cast it into slip molds of planters and fire to bisque temperature. The planters would be given away to the studio members or people who bought from us. We use cone 6 clay and glazes. Sadly the 1:1 radio does not work for cone six. I guess because of all the fluxes in the glaze there is too much melt. The trial included slip casting a diaper bowl mold and took some shards to get fired. I put them in a throw away bowl just in case it didn't work right. What came out was a bloated blistered mess. Later on a tried about a 3 parts clay to 1 part glaze ratio and that worked better. I haven't casted and tried a full piece yet, but I will soon!

Please note because of the colorants in the glazes any molds you use will be contaminated with the glaze so they won't work well for slip casting normal ware any more. Since the molds were donated to the studio I didn't mind messing them up.

[patspots]

Jennifer Harnetty, on 28 June 2010 - 08:05 AM, said:

In the Ceramic Arts Daily blog today, I posted a recent article from Ceramics Monthly on the efforts of several university ceramics programs to reduce their environmental impact. I thought I would try to continue the discussion here. So, read the article and then share your thoughts. Will these practices work for the average studio potter? What are you doing to make your studio practice more green?

Interesting reading, but... We are constantly searching for alternative energy sources, in fact, we are studying the possibility of having a solar farm. The U of O and the vegetable oil fired kiln look like labor intensive projects. Not so practical for the one man show, especially if pottery isn't all one does.

[m.cassels]

I used a reverse draft, Australian design kiln with a drip burner and used crank case oil in the eighties. I got the oil from a service station that attended trucks bringing minerals down from San Antonio de los Cobres, in Salta, Argentina. This oil had a lot of very fine copper-containing dust in suspension, so my reduction firings often produced interesting red flashes on the pots. I also had to lie on my stomach to rake out the pebbles accreted from the dust. The roar of the kiln was almost deafening, and it billowed out black smoke which fortunately, there not being any close neighbours, was not reported to environmental authorities.

Nowadays I use a natural gas kiln, often adding wood at the end of the firing. But gas provision in the pipeline varies from hour to hour, so firings that should normally take some 16-18 hours can stretch out to over 30. I also save up frying vegetable oil (not much, as I don't go in for fries and live on my own) which I drip in through the spyhole. But, while I love the effects of 'dirty' firing on my pots, I would be very happy indeed if someone were to come up with a cheap solar kiln, even for firing one small piece at a time, for perfectly clean porcelain firing. In this part of the world, we enjoy absolutely clear skies and intense sunlight all through August, September and October...

[Mike@riverrun]

Interesting topic. I am a one-person studio potter who works out of a 1,000 square foot space in my house that is designed the studio around sustainability. I fire electric. All my failures (bisque or glazed) get broken up using a box and a tamper used for asphalt work and is used behind retaining walls, in steps and along paths around the house. All glaze water uses to wash bottoms, etc., goes into a 5 gal bucket where it settles out and the clear water either goes down the drain or is cycled through my glaze spray booth. The glaze is concentrated and test fired with each glaze firing. If it turns out well, it becomes Slop I, Slop II, etc. If, like a good wine it is not ready yet, more goes in. Most of the time it comes out a bronze color used on outside of functional pots.

Clay slop goes down a separate sink made from a laundry sink and into a 30 gal tank where it settles. The clear liquid then goes outside into a 125 gal tank that also captures my air conditioning condensate and then is used to water plants in the yard (no veggies though). All clay is recycled in a small pug mill. The objective is to recover 100 percent of the clay, and so far, after 4 years, I am succeeding. Over the years, I have reformulated my glazes to get rid of heavy metals as oxides.

I make functional ware. My greenware accumulates so I have all kinds of sizes to as tightly pack my electric kilns as possible. The most product for the firing. Glaze firing is the same, every shelf full with no more than a quarter inch spacing between pieces.

I regularly (3-4 times a week) mop and wipe down the clay dust, this water is recycled as well.

The spray booth, made from two laundry tubes, on stacked inverted on another and an opening cut out, uses a circulating pump through a copper pipe with holes in it that creates a cascade of water to trap the spray and is recirculated. At the end of the glazing, this goes into the glaze settling bucket.

As a potter of one, I would like to here from other small operations.

[pepe810]

A huge topic in sustainability is how to manage a studio, cleanliness, environmental control, disposal of waste material, wastewater management, dust control etc.

[Sherman]

patspots, on 28 June 2010 - 10:49 AM, said:

Interesting reading, but... We are constantly searching for alternative energy sources, in fact, we are studying the possibility of having a solar farm. The U of O and the vegetable oil fired kiln look like labor intensive projects. Not so practical for the one man show, especially if pottery isn't all one does.

patspots,

It's interesting, you know, that most clay folks are already fairly frugal and smart about resources. As a group, they also tend to be fairly environmentally conscious. But, as with any big issue, we do tend to get enamored of ideas that are "revolutionary." Sometimes, though, the little things end up being not so little. Like most folks, I'm not really in the position to change my firing methods or my kiln, but I do collect rainwater and the condensed water from a dehumidifier. Even when I am super active in the studio, I have more water from these sources than I can use---and that's after watering the garden as well. My point is that, this one small thing prevents the treatment, processing, delivery (and associated payment for) hundreds of gallons of water in just one season. It's a small thing, but it makes a tangible difference. In this case, thinking small might be the better way to go. There are always reasons a particular studio is not conducive to a given solution or tool or method, but there are just as many others that are viable---and easy.

Be well,

Sherman

[hansen]

Jennifer Harnetty, on 28 June 2010 - 08:05 AM, said:

In the Ceramic Arts Daily blog today, I posted a recent article from Ceramics Monthly on the efforts of several university ceramics programs to reduce their environmental impact. I thought I would try to continue the discussion here. So, read the article and then share your thoughts. Will these practices work for the average studio potter? What are you doing to make your studio practice more green?

(1) Iron as a colorant. This has the widest color range. Opaque matt or bright translucent pale blues. Chun blues. Celadon greens. Tea dust greens. Yellow ochre yellows. Calcium/Iron reaction yellows. Pale rice hull yellow-buffs. Firey Oranges. Terra cotta orange. Shino pinks. Iron Reds. Brick reds. Chocolate browns. Black. What did I forget? Avoids use of heavy metals or toxic metals as colorants.

(2) Shards or sherds from discarded, fired pots. These can be used as mosaic, or as gravel.

(3) Dipping and pouring as a means of glazing. This eliminates the over spray later needed disposal or recycling.

(4) Grabbing a shovel and digging clay from backyard. Can be added for it's color as a controlled percentage in the slurry stage of clay-making process. No carbon foot print of moist clay shipping.

(5) Mystery Glaze. This can be tweaked and tested over many firings. Utilizes waste glaze. Typically Mystery Glaze becomes a black glaze, but if the potter tests base glazes without colorants first, then there is a plentiful supply of white and pale glazes for the mix.

(6) Water comes into the studio but does not flow out. All water is used as glaze water or as slop. Slop bucket at potters wheel is recycled back as "starter" when clay-making.

(7) Clay making method is now foot-wedging. This makes as much clay as fast as a small electric powered clay mixer can. Slop gets utilized as does dry recycled clay, crushed, slaked, blunged. Feldspar is added, with some clay, in the slop stage, then added to the dry clay & grog and foot-wedged.

(8) The use of open-bodied stoneware makes recycling at all stages much easier. When clay is then recycled, it achieves a uniform moisture and consistency almost by itself. Medium or fine grog, and sand about 100-200 mesh can be added, as well as coarse clays like kaolin or fireclay.

(9) Whether clay is wet-mixed or dry-mixed or a combination of the two processes, Japanese chrysanthemum wedging is preferred as it de-airs the clay, making use of the de-airing pug-mill unnecessary.

(10) Oxidation or neutral firing, most of the time. Potters face an inevitable time frame on this one. Wish I had more to say about it. I know of one kiln design that fired reduction in the first chamber and oxidation in the second chamber, I am wondering if this would help in terms of air quality at the flue?

(11) wish list: kick-wheel, wind power option on my electric. Not available in this area with mega-corporation power company.

(12) desire to make a few good pots. Work when inspired. The world doesn't need my more mediocre products anyway.

- h a n s e n -

[hansen]

[
(1) Iron as a colorant. This has the widest color range. Opaque matt or bright translucent pale blues. Chun blues. Celadon greens. Tea dust greens. Yellow ochre yellows. Calcium/Iron reaction yellows. Pale rice hull yellow-buffs. Firey Oranges. Terra cotta orange. Shino pinks. Iron Reds. Brick reds. Chocolate browns. Black. What did I forget? Avoids use of heavy metals or toxic metals as colorants.

oh yeah - kaki (persimmon) & tessha (russet) - some russet colors range toward olive green, others towards oranges, very nice ethereal color -

okay, what else did i forget?

Iron RULES!

[kathaleena]

hansen, on 02 July 2010 - 02:57 PM, said:

Jennifer Harnetty, on 28 June 2010 - 08:05 AM, said:

In the Ceramic Arts Daily blog today, I posted a recent article from Ceramics Monthly on the efforts of several university ceramics programs to reduce their environmental impact. I thought I would try to continue the discussion here. So, read the article and then share your thoughts. Will these practices work for the average studio potter? What are you doing to make your studio practice more green?

(1) Iron as a colorant. This has the widest color range. Opaque matt or bright translucent pale blues. Chun blues. Celadon greens. Tea dust greens. Yellow ochre yellows. Calcium/Iron reaction yellows. Pale rice hull yellow-buffs. Firey Oranges. Terra cotta orange. Shino pinks. Iron Reds. Brick reds. Chocolate browns. Black. What did I forget? Avoids use of heavy metals or toxic metals as colorants.

(2) Shards or sherds from discarded, fired pots. These can be used as mosaic, or as gravel.

(3) Dipping and pouring as a means of glazing. This eliminates the over spray later needed disposal or recycling.

(4) Grabbing a shovel and digging clay from backyard. Can be added for it's color as a controlled percentage in the slurry stage of clay-making process. No carbon foot print of moist clay shipping.

(5) Mystery Glaze. This can be tweaked and tested over many firings. Utilizes waste glaze. Typically Mystery Glaze becomes a black glaze, but if the potter tests base glazes without colorants first, then there is a plentiful supply of white and pale glazes for the mix.

(6) Water comes into the studio but does not flow out. All water is used as glaze water or as slop. Slop bucket at potters wheel is recycled back as "starter" when clay-making.

(7) Clay making method is now foot-wedging. This makes as much clay as fast as a small electric powered clay mixer can. Slop gets utilized as does dry recycled clay, crushed, slaked, blunged. Feldspar is added, with some clay, in the slop stage, then added to the dry clay & grog and foot-wedged.

(8) The use of open-bodied stoneware makes recycling at all stages much easier. When clay is then recycled, it achieves a uniform moisture and consistency almost by itself. Medium or fine grog, and sand about 100-200 mesh can be added, as well as coarse clays like kaolin or fireclay.

(9) Whether clay is wet-mixed or dry-mixed or a combination of the two processes, Japanese chrysanthemum wedging is preferred as it de-airs the clay, making use of the de-airing pug-mill unnecessary.

(10) Oxidation or neutral firing, most of the time. Potters face an inevitable time frame on this one. Wish I had more to say about it. I know of one kiln design that fired reduction in the first chamber and oxidation in the second chamber, I am wondering if this would help in terms of air quality at the flue?

(11) wish list: kick-wheel, wind power option on my electric. Not available in this area with mega-corporation power company.

(12) desire to make a few good pots. Work when inspired. The world doesn't need my more mediocre products anyway.

- h a n s e n -

[kathaleena]

For Hansen: Would you please explain what foot wedging and Japanese chrysanthemum wedging are? Thank you!

[hansen]

kathaleena, on 05 July 2010 - 10:20 AM, said:

For Hansen: Would you please explain what foot wedging and Japanese chrysanthemum wedging are? Thank you!

Now I'm not sure if I used the right terminology. Anyway, here is a pic of both and wedging and foot wedging, just posted to my blog site. Like I said, both methods de-air the clay. This clay is settled liquid clay, not dry-mixed, in the first place, so it won't have air bubbles. They aren't really always a problem in firing, but they can be a real hassle when throwing. Either way there isn't really anything good about them.
h a n s e n

[hansen]

hansen, on 06 July 2010 - 05:16 AM, said:

kathaleena, on 05 July 2010 - 10:20 AM, said:

For Hansen: Would you please explain what foot wedging and Japanese chrysanthemum wedging are? Thank you!

Now I'm not sure if I used the right terminology. Anyway, here is a pic of both and wedging and foot wedging, just posted to my blog site. Like I said, both methods de-air the clay. This clay is settled liquid clay, not dry-mixed, in the first place, so it won't have air bubbles. They aren't really always a problem in firing, but they can be a real hassle when throwing. Either way there isn't really anything good about them.
h a n s e n

p.s. sorry that they aren't active links...(?) I guess with all this high technology or whatever... have to cut and paste..

[kathaleena]

hansen, on 06 July 2010 - 05:18 AM, said:

hansen, on 06 July 2010 - 05:16 AM, said:

kathaleena, on 05 July 2010 - 10:20 AM, said:

For Hansen: Would you please explain what foot wedging and Japanese chrysanthemum wedging are? Thank you!

Now I'm not sure if I used the right terminology. Anyway, here is a pic of both and wedging and foot wedging, just posted to my blog site. Like I said, both methods de-air the clay. This clay is settled liquid clay, not dry-mixed, in the first place, so it won't have air bubbles. They aren't really always a problem in firing, but they can be a real hassle when throwing. Either way there isn't really anything good about them.
h a n s e n

p.s. sorry that they aren't active links...(?) I guess with all this high technology or whatever... have to cut and paste..

[Stillwater]

In the book Making an Installing Handmade tiles by Angelica Pozo, there is a method described to test tile clay for extreme cold outdoor use but also a reasoning for why certain clays work and others do not. (page 126)
This is a terriffic book to own. I used this test prior to creating an outdoor tile mural for a school. It was definitely worth the time to test.

I found the method printed out on another clay thread

From research by Dr, brownell and other Ceramic Engineers at Alfred via
Ted Randall, Val Cushing....

From "Cushing's Handbook", 3rd edition

"To determine if your clay body is safe from cracking under freezing and
thawing conditions, find the C/B ratio by the following lab test
procedure.

1. take a sample of your clay body and take the dry weight. You must
weigh carefully and accurately
Record this weight as D

2. Immerse this sample in water for 24 hours. DO NOT Boil the Water.
(just immersion, not boiling or heated water)

3. Take the saturated weight (after 24 hours in water)
Wipe off the surface water and weigh carefully.. Record the weight as C

4. Replace the sample in the water (immersed) and BOIL THE WATER. Leave
the sample in the boiling water for Two Hours
5. After two hours of boiling, wipe off the surface water and carefully
weigh the samples. Record the weight as B

6. us the weights determined above in the following formula:
D represents: Dry Weight of fired Test sample
C represents: WET weight
B represents Boiled weight

(1). C-D /D = 'C; value.(i.e., wet wgt minus dry wgt divided by dry
wgt gives "C" value
(Note that "C" value is different than 'C' weight above)

(2) . B- D/D = "B" value. (i.e., boiled weight minus dry wgt, divided by
dry wgt gives "B" value

(3). "C" value divided by "B" value = "C/B ratio".

The final result must be less than 0.78 to indicate that a clay body is
safe for outside use in winter, freezing and thawing situations.
This is the standard used in the Ceramic industry