Cob Do I really need sand in my clay?

[FROG]

>In answer to your question about the cracks, I think it has more to do 
>with the rate of drying than the ration of materials.  That is to say if 
>you let the clay dry too quickly the wall will crack.  In Germany where 
>I worked building houses out of a straw and clay mixture, and plastering 
>them with a sand/clay plaster we wet the walls down with a brush and a 
>slip coat to stop the cracking.  Good Luck.

     Adam:
     
     Do you do this after the earth plaster has completely dried?  The slip 
     coat sounds primarily like a crack filler.  Yes?  Do you add sand to 
     your clay slip coat?
     
     Thanks
     
     sam
     
                                               
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 Sam Droege  FROG at NBS.GOV                      
 w 301-497-5840 h 410-798-6759 fax 301-497-5784
Dodon Farm

All nature wears one universal grin.
      -Fielding - Tom Thumb the Great.