A deposit of sand kaolin in Garza County, West Texas.

The equipment needed can easily be assembled:

1. Several 3-gallon plastic buckets.
   
2. One sieve made from a piece of discarded window screen stretched over an 8x8 inch wooden frame.
   
3. One old, discarded 3 or 4 inch paint brush.
   
4. Several plaster bats. 14x16 inch bats are recommended as they handle easily and are large enough to re produce a fair amount of clay. These bats should be at least 1 ^1/2 inches thick to absorb the moisture from the clay slip.

All clay that has been brought in from the field must first be dried-out before any processing can take place. This is necessary because of the amount of natural oils which retard the slaking of the clay. A clay should be exposed to sun or kept in a dry place for at least two weeks before being used. This drying period can be omitted when using powdered clay from brickyards or so-called mortar mixes.

When the above equipment has been assembled and the clay has been dried-out thoroughly then the clay can be processed according to the following five steps:

1. Remove most visible stones, pebbles, and twigs from the clay by hand; if the clay has formed larger lumps, break these up with a mallet or hammer.
2. Fill several of the buckets with the dry clay and add enough warm water to completely cover the clay. Let this mixture soak at least over night. The water will slake the clay (break up the clay into fine particles).
3. Next day stir the clay well adding water if necessary to form a slip. Slip is clay in liquid form. The consistency of the slip should be such as to enable the clay to be worked through the sieve into a clean

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bucket. The best Consistency is when the slip has the quality of thick cream.

4. The clay is then worked through the screen with the brush. This action removes any stones and foreign matter that still may have been in the clay. The mixing action of sieving the clay will aid a more uniform distribution of the clay particles.
5. The buckets with the sieved clay are left to stand overnight. The clay will settle on the bottom and any surplus water can be poured off the next day. The thick slip is poured onto the dry plaster bats. The dry plaster will absorb any excess water from the clay and after several hours, the clay cakes will be ready for wedging.

Testing the Physical Properties of Texas Clays

The physical properties of a clay are defined as its Plasticity, fusibility, color, texture, tensile strength, shrink age, slaking, absorption, and specific gravity. From these most important to know within the limited uses of a small scale production are: plasticity, fusibility, color, texture, and shrinkage in that order.

Plasticity can be defined as fat (highly plastic) or lean (low plasticity) clay. Sand decreases plasticity and when present in excess makes a clay un-usable. Plasticity can be simply tested by rolling out a coil of clay approximately the size of a pencil and winding this coil around one's finger. Good plastic clay should show no cracks. Lean clay will re veal coarse cracks or break apart entirely.

The changes occurring in the clay during the firing, namely the firing shrinkage, volatilization, of some of the components, and densification of the clay are referred to as fusibility. The maturing temperatures of a clay can be deter mined by a fusibility test. A simple way to carry out this test is to form several cones of the clay body approximately ^3/4 inch wide at the bottom and 4 inches high. Then submit the cones to four different firings at varied cone ranges. For example: fire one of the four cones to cone 04, one to cone 1, one to cone 4 and the last one to cone 8. Be sure to prop the cones into a wad of clay for support and place the cones on a piece of brick or previously tested clay so that they can do no damage to kiln or shelves when they start to deform. This

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