The Keyo method
The clay is dug out, wet or dry, and is broken up into small pieces. Water is carefully added, and the wet
clay is wrapped in polythene paper and left to soak up the water. When the clay is soft, the correct quantity
of sieved sand is added
and mixed using a
spade or hoe. The
correct mix will depend
on the type of clay. This
mixture is pounded or
trodden to crush any
lumps, then wrapped in
polythene and left to
rest. After this, the clay
is sorted by hand to
remove any stones or
lumps. It is then
wrapped in polythene
paper again and rested
for at least a few weeks
until ready for use.
Fig. 3.3 The Keyo method
Whichever method is used, the important things to remember are:
• The clay must have no stones or lumps in it.
• The clay must be very well mixed.
• The clay must be rested enough for it to be plastic. This may be days, weeks or even months.
Resting allows several important changes to take place in the clay structure. In addition, it makes
the clay plastic and workable.
• The clay should have a high sand content (or other non-clay particles) but must still be workable.
• The clay mixture must be consistent. You must ensure that you use the same amounts of clay,
sand, and other additives every time.
Other additives
There are other ingredients that potters sometimes add to their clay. These fall into two main categories:
Non-clay particles that serve the same purpose as sand. Examples of non-clay additives that "open
up" the clay and reduce shrinkage include:
• termite soil
• volcanic ash
• grog. This is finely ground fired but broken pottery, which is hard to grind by hand. Fine sand,
if available, is often a better choice. Alternatively, you can manufacture grog by grinding and
sieving dried clay then putting it in a pot in the fire or kiln.
Fine biomass particles that bum up during firing, leaving small spaces in the pottery, thus making
it lighter and more porous. Examples of biomass additives that bum out during firing, and open up
the clay are:
• rice husks, wheat chaff, coffee husks
• sawdust
• finely chopped grass
• charcoal dust
• cow dung. This is mainly composed of biomass. (The bacteria help to mature the clay.)