Cob: we need experimentation

[Bob]

Dear Tami and Judi,

While you are gathering information from others you might do a real service
to all of us by becoming good back yard scientists.  Make some good sized
blocks, perhaps two foot long by a foot high by a foot thick with different
mixtures and see how strong they are.  After they dry out for a week,
assuming you have hot sun at this time of  year, test them in different
ways: check the size of the cracks, hit them with a hammer, drive a screw
driver into to them.  Then get two short pieces of wood approximately 4
inches round or 4x4 square and put one under each end.  Then stand on the
middle to see if they break.  This tests their tensile strength.  You might
even put the lawn sprinkler on them to see how well they would stand up to
rain that blew under the eves in windy rainy weather.  If either or both of
 you do this please report your findings to the cob list to benefit all of us.

If your pine needles are long enough they should be good reinforcers,
reducing the size of the cracks but since they will not compact as much as
straw they may not work as well.  Palm leaves and rice straw would be good
to try, as might narrow strips of corrugate carton. If anyone on the cob
list has tried any of these please share your result with us.  
Bamboo is a reenforce better then steel.  Split it in half or smaller
strips.  It might grow well in your area but be careful.  It can take over
and be hard to control.  It could become a little income producer it has so
many uses.

Finding free clay. Since you don't need good quality potter's clay it
should not be too difficult.
1. Dig deeper.  You may be surprised.  You might be able to turn the hole
you make into a well, root cellar or for something else useful if you line
it and cap it well. .
2. Phone the geology department of your nearest college.  They should be
able to tell you where to look.  
3.. Go to the nearest potter.  Perhaps she or he has done some local
exploring and can tell you where there is clay too inferior for pottery but
fine for your use.  Better get permission from the owner of the land before
you take too much..
Hope these ideas are useful.  
Bob Luitweiler