mixing cob in sandy soil

[goshawk at gnat.net]

I came up with a way of making cob with my soil that seems to work 
fairly well. I think it's geared toward the sandy soil though.  
Basically I have this old electric cement mixer I picked up for $50. 
My soil has very little clay or organic matter in it. I must get clay 
from the local sand pit (Kaolin clay mainly) I put this in the cement 
mixer with water and let it run creating a clay slip that's a bit 
like thick chocolate milk.  Once the slip is made I take the slip and 
add about 6 to 7 large coffee can's full into a wheel barrel full of 
sand.  I mix this till the the moisture is about uniform and then add 
some straw, mixing again.  The mixture is a bit drier than cob 
because using the  super adobe bags you are working more like rammed 
earth. I have made some bricks with this (I had to add a bit 
more water to make the bricks) it seems to work good.  Getting the 
slip mixed uniformly in the sand is easier (relatively speaking) than 
using a screen to break the clay up and mix it dry with with the 
sand. 
When  I make cob to for building without bags, I will add a couple 
more cans of slip to increase the moisture content so it will be more 
workable.

Pat 
Mauk Georgia

"Any sufficiently advanced technology is indistinguishable from magic" Arther C Clark