[Cob] Earth floors

[Amanda Peck]

I've run it through the--half-inch--screen as dry as possible--not very, 
given that the clay pile is outside--which means that we basically extruded 
bits through the screen, letting the easy stuff go on down (into a garbage 
can) and sometimes putting the bigger pieces away for later consideration

But I'm using galvanized wire mesh, the kind you use for rabbit cages.  Not 
all that likely to break, in the two-foot square we were using, in other 
words.

And there's plenty left in the garbage can after we did a 100sf floor at 
about an inch and a quarter deep in one step.  The mixture WAS less than a 
quarter clay.  We were able to use one clay, three sand, and maybe a bucket 
of wood shavings, no idea what you're having to use.

But seems like some people are getting themselves SOME powder/dry clay, and 
mixing the rest into a slip, pouring that through their screen, drying it 
out in the final floor mixture with sand and their clay powder, and wood 
chips or sawdust or whatever.  I guess you'd want to add a lot of water, mix 
a lot, let it stand maybe overnight and take off the nearly pure water that 
accumulates on top, pour the next layer through that or even a finer screen, 
with or without the stones that have accumulated on the bottom.  Using the 
ubiquitous 5-gallon buckets--3-gallon if I can find them and they're not too 
much more than the 5  (they sell fewer of them).

A third way, (if you've got one of those concrete mixing tubs or a shallow 
rubber-like tub and enough wire mesh to make a basket to fit it,)  might be 
to lay the mesh basket in the tub, put as dry as possible clay in there. 
pound with a mallet, then lift the basket, shake out all the small stuff, 
pour the now sifted contents of the tub into something else, repeat.  (I 
really have pounded very dry clay in a tub, poured out what will go through 
the mesh, and repeated)

But take care of your hands!  Pure clay is pretty sterile, but just dirt 
isn't, and the particular composition of the soil bacteria varies wildly, 
from stuff that pediatricians wish that more toddlers were exposed to, to 
mildly stimulate their immune system, on.

Ed wrote:

     I am having a problem processing enough clay for a floor finish.
     The first step is to wet it and mix it with a power mixer then I push 
it
through 1/2 inch screen. This gives me a tapioca-like mixture of clay 
tapioca
balls mixed with a few very sharp quarts rocks.
     The next step is add more water, mix it again and push it through a
window screen. This is where the problem occurs. When I place an aluminum or 
nylon
screen on top of the 1/2 inch screen and try pushing the clay through it is 
a
very slow process. I cut up my right hand Tuesday, my left hand Wednesday 
just
making one batch a day, and I am not looking forward to five more batches
needed to finish. I can wear dishwashing gloves or a wooden block taped to 
my
hand to protect it from the sharp rocks, but if I use more force to speed up 
the
process it tears the window screen.
     Today I am going to try 1/4 inch screen and then two layers of 1/4 inch
screen set at a 45 degree angle with a power mix between steps to get rid of
the tapiocas. This stuff is tough enough to take lots of force. Then I when 
I
get to the window screen it is my hope that most of the sharp rocks will be 
gone
and I can use a little more force.
     If this does not work I am not sure what to do. I am slated to help 
Chris
do his floor next. He wants the same nice red clay as I am using for my 
floor
and his floor is twice the size of mine.
     I tried finding a supplier for stainless steel screen but cannot seem 
to
find anyone who wants to sell small quantities.
     Does anyone have ideas? Someone must have had this problem before me.
Ed