How to prepare clay for a molding?
the Dried clay should be shattered small the wooden hammer and to fill up in the low plastic capacity filled to a half with water so that the sheet of water over clay made 5 - 10 centimeters. Next day carefully to stir mix a wooden oar. The clay suspension having density of cream is formed.
Now it is necessary to remove large mechanical inclusions. Suspension should be filtered through a sieve with a size of cells 36 - ti openings on square centimeter or is thinner. To leave the filtered clay to stand on two - three days. During this time clay will accumulate on a tub bottom that will allow to remove excess water by means of a siphon.
In the industry from liquid masses use to removal of excess moisture various the filter - the press, but we will try to do without them. It is possible to evaporate, of course, excess of moisture, but clay to clay discord, and in some them them can remain too many the dissolved salts. At a molding of salt do not disturb, but at further operations, for example, at glass glazing, can significantly do much harm.
The primitive filter can be built from a linen bag. It is filled with liquid suspension and suspended. Further bags are removed and stacked on well dried up plaster boards. If bag fabric not really dense, together with water is washed away many clay particles and if too dense, then process of a filtration is strongly dragged out. In this case from above put oppression on a bag. Here to you and the filter - a press.
If clay nevertheless remains damp, it can be dried before some hardening in the warm place, for example, at heating radiators, and it is better just in the dry room as the overdried clay badly razmokat and forms difficult dismissed pieces.
It is necessary to leave freshly cooked clay for some time on air, under the canopy protecting it from dust. For such vylezhivaniye it is better to use winter months of year. The most optimum is considered to stay in bed clay on tables with a zinc covering.
In what here a secret? In the course of a vylezhivaniye clay is affected by microorganisms which do it more plastic. And so, zinc serves as the catalyst for such activity of bacteria, promotes improvement of quality of clay.
For the same reason the clay dried to standard should be stored in densely closed boxes zinced from within. There it is left for ripening for the term of not less than a month. The longer clay dough matures, the it becomes better, more plastic.
The dough placed in a box should be protected from drying, having covered it with damp fabric. Not to care for frequent moistening, fabrics should be made so: on a bottom of a zinc box to deliver to a ditch with water, over it to lay boards so that they were in 7 - 8 centimeters from a water surface, to lay clay on boards, and to ship the ends of the fabric covering clay in water in a ditch.
Too soft clay is very pliable, is easily formed, but it sticks to fingers and can be deformed under the influence of a body weight. In the course of drying of a product from such clay strongly contract.
Normally prepared clay has to take easily the necessary form under the influence of insignificant efforts too, and its separate pieces can stick together with each other, but it should not stick to hands any more. Such clay allows to form from it quite big products, and they are not deformed under the influence of a body weight in the course of formation.
However it should be added to it literally a water drop as it becomes excessively sticky again. It is also criterion of optimum extent of drying of clay. From such clay it is the best of all to form big vessels and to mold sculptures.
And now - let`s get down to work!