Pottery Machines

Project goals:

To develop a sustainable system for finding, creating, and selling pottery.

Contact info:
Ian Rice iarice@calpoly.edu
Howard Reiss hreiss@calpoly.edu
Frank Hanna fhanna@calpoly.edu

First step:

We will be creating a pottery wheel that can be built from local, inexpensive, and easily found materials. The pottery wheel would be fairly simple and therefore suitable for maintenance and repair on the spot.

Second step:

We are also looking into building a low-tech kiln to fire the pottery in. Kiln should be easily constructed from readily available materials in the San Pablo area, and also easily maintained. We are hoping to consult with people who have experience with making kilns and firing clay.

Third step:

Develop a system for processing natural clay into usable material for pottery.

Progress:

Step 1
Proof of concept prototype, Jan. 19th 2001: We have built a wheel using an old car tire mounted on a floor flange and a pipe nipple. Here is the video that was our inspiration and a couple photos of our progress.

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Prototype mechanism build on January 19

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Prototype 1:

Prototype 1 preliminary diagram – 1/24

Assembling base frame – 1/24	Base frame complete – 1/24	Adding panels to base for stability – 1/24
Bolting down Prototype 1’s turning table – 1/24	Ian gets it rolling – 1/24	Success!

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Decision Matrix 1:

Prototype 1 Testing – January 31st:


Formin the clay – 1/31

Getting Creative – 1/31

First pottery thrown on wheel – 1/31

= Prototype 1 functions well, and is relatively easy to use. We just need a little more practice with thowing pottery : )

Prototype 1- fine tuning

Addition of arm rest and bat

Step 2
Prototype 2 ~ Kiln:

Idea (skip ahead to 4:00):

Materials Needed:
-Steel Trash Can or Barrell
-Saw Dust
-Shredded Newspaper
-Pots for firing

Prototype 2 Trials:

Kiln Shell Material Decision Matrix:

Kiln Fire Fuel Decision Matrix:

Prototype 2, Kiln results:
– We were able to fire a couple pots, and as you can tell from the images the pottery was saturated in ash, but had become hard.
-Kiln seemed to be getting hot enough, but we had no way of measuring its temperature.

Adjustments:
– Added a chimney attached to the bottom of the barrel to allow for the kiln to circulate ash and oxygen.
– Wrapped pots in aluminum foil to protect from the ash.

Adjustment test results (February 27):
– Kiln still became very hot, but still have no way to check the temperature range achieved.

Temperature test results (March 6):
– We used pyrometric cones to estimate temperature of the kiln.

• Pyrometric cones are designed to deform at certain moments during a firing. This deforming action allows us to either shut the kiln off at the proper point or simply to record what happened during the firing.
• We used a Cone 06 and a Cone 018. See temperature chart: http://www.evenheat-kiln.com/porcelain/technical/conechart/chart.pdf
• The 018 had completely disappeared during the firing and the 06 had deformed slightly.
• With this we estimate the kiln to reach temperatures between 1400-1600 degrees.
• From this, we ill be able to determine what lead-free glazing we will be able to use for the pots.

Step 3
Clay Processing
– We began the process by digging on campus for some high clay soils (dirt that stays formed together when you squeeze in your hand). Luckily California has many high clay soils that we would be able to work with.

supplemental video:

-Next, we let the soil dry in sunlight for a couple days (2-3).
-We then began processing the dirt by passing it through two screen to remove rocks and other aggregate materials (see pictures).

Crushing dried clay -3/9	pour dirt through screen to remove pebbles or sticks -3/9	run dirt back through the process with the finer screen -3/9	-your left with fine clay soil -3/9	clay is then combined with water so any remaining wood or rocks float -3/9
mix clay (preferrably with drill mixer -3/9	work it!	work it! (add sand if too wet)	work it! (to a toothpaste texture)	you’re good to go!

Using clay, forming pots on wheel, and firing :
Natural clay => pot


Pot =>fire

After the first two firing we decided to add a down draft system to the kiln (see figure below)

-This system helps circulate air through the kiln, helping it maintain a higher temperature throughout.
-This was done fairly easily, we cut a small (approximately 6″ hole) near the bottom of the kiln and attached some standard duct piping that extended about 6.5′ above the ground. (see images)

ADDITION OF DOWN DRAFT SYSTEM

Where is this going?

• žThe whole process will need to be perfected in its final location so environmental variables like clay type and available materials can be addressed.
• ž If another group wanted to adopt this project, it would be fairly simple, but our recommendation is that they first establish a dialogue with someone interested in San Pablo before continuing.
• ž Working with water sanitation group seems promising if their clay filter seems to be the direction they’re going.

CONCLUSION

• žAs part of our initial goal, we intended to process clay, make pots on our own wheel, and then fire them in the kiln of our design. During week 10 of the quarter, we were able to accomplish this goal.
• žDuring last Monday’s lab (3/7), we found natural clay from sources on campus, and laid it out to dry. Wednesday, we finished screening and processing it, and then threw two pots. The pots then dried until Sunday, when they were fired using the kiln we built during the second half of the quarter. The following Monday the pots were retrieved from the kiln, one cracked during firing, but the other came out nicely.
• žUltimately, the designs are not not perfect, but both the wheel and kiln work far better than we though they would.
• žEstablish dialogue with someone interested in the project in San Pablo!