Cob: RE: Which straw?

[Rosemary Lyndall Wemm]

Eduardo,

Are there any reeds along the rivers in this forest?  These may work.  Or
you could try strong, fibrous [=woody], flexible stalks, if you can find a
plant with lots of them.  Some sorts of grasses might work.

Make some sample bricks using various long fibred things you find nearby.
Dry them for a few weeks.  Then support them at both ends and stand on them.
If they break then either your fibre is the wrong kind or the brick has the
wrong clay to sand ratio, or the wrong type of clay.  Too little clay and
the brick will crumble; too much clay and the brick will crack.  Some clays
are better and stronger than others.  This is just luck, because it depends
entirely on the type of soil in your area.   If you are lucky enough to have
the right kind of clay, and it has just the right amount of sand mixed with
it, then you can get away without using any straw or binding material at all
... but then you are not building in "cob".

Another idea worth considering is using manure from grass-eating animals as
a binder in the bricks.  It's rather smelly, but it's used quite
successfully in this way in some Middle Eastern countries.

- Rosemary

 ---------------------------------------------------------------------
 Rosemary LYNDALL WEMM,
 B.Mus.(Inst.), T.S.T.C., B.A.(Hons), M.A.(Neuropsych.), etc.  _--_|\
 Clinical Neuro-psychologist                             Perth/      \
 Perth, Western Australia    lyndall at neurognostics.com.au  -->\_.--._/
 ------------------- http://www.neurognostics.com.au ---------------v-