Cob jar test for soil

[Otherfish at aol.com]

uwe
the clay will settle out last & so will be on top
-it takes awhile to settle out
-so shake it up & come back when the water is pretty much clear

the best way I've found to gauge the clay content is to stick a stiff straw
into the top layers after its all settled - push the straw down till you hit
resistance
-that means you're at the sand / silt or clay / silt boundary
- pull the straw out & feel what part of it is stickey
-thats the area that is setteled out clay
-simple, easy.   & there's usually lots of straw around

I've foumd the jar test to be close to useless
-there's nothing quite so informative as learning about your soil's properties
by making a series of test bricks using equal component measureing
- mix one or two measures of your soil with just enough water to make a
plastic mixture
if its stickey  - add sand
if its sandy   -  add clay
(work with a consistent measure unit so you can keep track of your
proportions)

push it till its too sandy & falls apart or is mongo stickey 
-use the ball drop test(toss & flat palm catch) to see if it fractures on
impact = too sandy
or 
the squeeze & palm hang test & if its messy sticky goo = to much clay  
-then back up a bit from the sand or clay adding direction you were going
and there you have it
-the last step is to mix a batch with these determine proportions & build with
it and do a final adjustment to make it easy to work with & still staying
intact 

-developing this tactile / kenetic relationship with the mix will tell you
about a million times more about your materials than the jar test can

cob on
john fordice
TCCP
otherfish at aol.com