Cob: RE: RE: CEBs

[Lance Collins]

Michael Fitzgerald wrote:

>Which brings me to some musings on machine mixing cob. Has anybody tried
>mixing straw and dried screened soil and then just adding water? The BASIN
>publications suggest that soil could be prepared on a large scale with
>impact mills and pulverizers. The idea is to get the lumps of clay as small
>as possible so that they bind well with the straw and sand in the mix. It
>just seems to me that bringing clay and straw together would be easier when
>they are both dry. I might try it this weekend if nobody writes to say
>they've tried it and it doesn't work.

This works for making a mix to place in moulds either for blocks or pouring 
in place (poured earth).   But for cob the mix needs to be stiff enough to 
sit in place on top of the wall without formwork.   You can't achieve this 
amount of stiffness with a cement mixer.  You just get stuff stuck in the 
base of the mixer bowl with balls of mix rolling around on top.  You can 
scrape the mix out of the mixer a couple of times before you decide there 
are better ways to spend your time.

There might be soils out there which work but certainly not mine.

Lance




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