How to Mine or Recycle your own clay

Written July 18, 2005
Revised January 30, 2008

The first thing you will need to do is build a form for a plaster bat.

This is the outside form:

It is built using 2X4's and plywood.

Outside dimensions are 36 by 24 inches

This is the inside form:

Dimensions are 26 by 14 inches

Seal all inside joints with caulk

Nail the two together thus

(this is a demo only - use more nails)

Before you did this you should have taped a layer of cardboard to the inside vertical surfaces to make sure you can remove the form without destroying it.

Mix up a big batch of plaster and pour it in there, tapping regularly to avoid the voids and bubbles, like any casting process.

Then you get a piece like this, the top edges are 3 inches thick:

And this in profile:

Next step is to go and get some clay. Either dig it yourself or get that bucket of wheel slop and trimmings. If you are starting out with dry clay: smash it into as many small pieces as practical so it can more uniformly absorb the water

You'll need 5 gallon buckets, a lid with a hole cut in it, an industrial strength paint mixer, a 1/2" electric drill (1/3 horsepower or equivalent), boots, a hose, a screen door screen, and a place to make a mess - preferably outside so you don't fill the drain with mud.

Stick that mixer into the bucket of slop and hold the lid down with your boot. Mix well

Then try to put it through the screen into an empty bucket:

What you'll find is that it's too thick to go through the screen so push it through with the hose. Then keep adding water to the slop bucket and mixing until it gets thin enough to go through:

The whole idea is to add enough water into the clay to get it through the screen. There are no measurements.

I find rubber bands, pieces of sponge, etc that I would rather deal with at this stage, than have it ruin a pot

The product. Two cans of slop will make four cans of screened clay

Alternately, you can use a bathtub as a settling tank (see the last picture)

What ever didn't make it through the screen leave in the slop bucket for next time .

Then clean up. And wait a month for clay to settle.

Check it every time you get antsy, then once you are convinced it isn't going to settle any more, siphen off the supernatent (the water) .

Drill a hole in the corner of the previously used inside frame so water has someplace to go:

Then line it with canvas and pour in the settled clay:

Depending on the humidity where you are, let the water evaporate off for a week or so. There are a number of variations on this theme. I think some people tie knots in the legs of a pair of jeans and let 'em out to dry. Do whatever works to remove water without letting the edges dry out.

Next step is to put the now fudgy mud into the plaster bat to further dry it:

Then spread it around:

This step may last for a day or so. As soon as I can remove it with my fingers, I remove it. It's at a nice soft stage and can be wedged or placed on another plaster bat to dry it to exactly the water content you like.

Be careful not to contaminate the clay with plaster chips:

I use the outer form as a wedging table:

The author using this technique in 1990 to mine native yellow clay.

in 2008 I bought this wonderful device

A Peter Pugger

Whereas all of the above steps are necessary for mining clay,
recycling with a pugger is a  breeze.

Just take any plastic clay and stuff it in the machine: mix, deair, pug


The new set up:

The product

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