How to Make Potter's Clay From River Clay

Making pottery clay from river clay brings the artist closer to nature.

For some potters, finding a river clay deposit is like a miner striking a gold vein. However, many may hesitate to bring home a bucketful because they are unsure about the process of cleaning natural clay to achieve the proper plasticity. Although time-consuming, making pottery clay from river clay provides a desirable medium while bringing the artist a little closer to nature.

Things You'll Need

• River clay
• Plywood sheet
• Shovel
• Dust mask
• Wooden mallet
• 5-gallon plastic bucket
• Water
• Medium outdoor plastic garbage can
• 40 mesh screen
• Plastic bag
• Large plaster of Paris block (optional)

Instructions

1. Lay a plywood sheet on the ground outdoors in a sunny location. Spread shovelfuls of river clay onto the plywood sheet, and allow the clay to dry out for two or three days.

2. Secure a dust mask to your nose and mouth. Pound the dried clumps of clay with a wooden mallet to break them up. Remove any pine cones, twigs, rocks or other debris from the pulverized clay.

3. Fill a 5-gallon bucket two-thirds of the way with water, then add half as much pulverized clay. Blend the clay and water into a thick, smooth slip, and allow to sit overnight, mixing occasionally.

4. Lay a 40 mesh screen on top of the plastic garbage can. Dump the slip from the bucket onto the screen to filter out any remaining debris. Remove the screen and discard the debris. Allow the slip to settle in the garbage can for one or two days. Pour off the excess water from the top.

5. Spread the slip onto the plywood sheet. Allow it to dry for two or three days until the clay is of working consistency, making sure to occasionally fold the edges into the middle to ensure even drying. This may take several days.

6. Test for plasticity by wrapping a pencil-size coil of clay around a finger. If the clay bends without breaking, it is ready to wedge. If the clay breaks when bent, it is too sandy. Repeat Steps 3 through 5, but use a finer mesh screen when filtering the slip.

7. Wedge the clay, then store it in a plastic bag until it’s ready to use.

Tips & Warnings

• Spreading the clay on to a large plaster of Paris block after screening will speed up the final drying process.

References

• Ceramic Arts Daily; Going Local: How to Dig and Process Your Own Pottery Clay; Graham Sheehan; May 2010
• Goshen College; How to Rework Clay and Fire Without A Kiln; Marvin Bartel
• Pottery Magic; Finding, Digging and Preparing Your Clay