Clay Treatment Effecting Plasticity?

[Mc Clue]

Total newbie question... is it possible for clay preparation processes to increase a clays plasticity? (ie. plastic bucket, power drill stirer) Have gathered clay from the same site twice, one batch lacking plasticity if anything, the next far too plastic.

[oldlady]

if you provide more information on what you call "preparation" someone can probably give a reasonable answer.  there is not enough info in your question.

[flowerdry]

I can tell you that natural materials from the ground like soil, clay, etc. can change composition in a surprisingly discrete (abrupt) manner. I don't mean time, but location.  What I'm saying is some natural factors in the area where you are harvesting the clay  could have caused pockets or whole areas of a variation in the clay composition.  What may look uniform to you might not be.

[Don Kopyscinski]

I can tell you what not to do.

Years ago, I was doing all kinds of experiments in the studio. I though that I may be able to increase the plasticity of the clay I was using. I tried several additives to my clay body. I had read that the addition of organic material to the clay could help it to age better. I read somewhere that if one adds "compost starter to the clay, it will promote the aging process. So I mixed it with water and sprinkled it evenly throughout a 10 gallon bucket of clay. I covered it, and left it alone to brew for about a month in the summer. When I decided to try it out one day, I was in for a surprise. On opening the bucket, I was struck by the most foul smelling, pungent, "bucket of vomit" type smell that I'll never forget it. I imagine that the plasticity of that clay was greatly improved. I had grown something in the clay, and I swear it had a heartbeat. The smell was unbearable, and the whole pail had to be disposed of in the great outdoors, as I held my breath. It seems that my experiment worked a little "too well". It was a valuable learning experience.

[Don Kopyscinski]

In reality, the plasticity of clay may be improved by mixing it to a slurry under continuous, vitreous, agitation first. The clay can then be allowed to stiffen to a working consistently, ( "filter pressed" in industry). This not only will this thoroughly blend the clay you are testing, it will fully wet the clay particles, yielding greater lubricity, thus maximizing the clay's plasticity. It may turn out that the clay is not fully workable as it stands, but it maximizes that particular clay's forming potential.