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Kiko Denzer on Art

[Cob] Q re: Clay-to-sand ratios?

Ocean Liff-Anderson ocean at
Sat Mar 15 11:14:27 CDT 2008

(Muddy Toenails - Thanks for writing.  I am posting my response to  
the list, because I think others need to comment on this as well.)

Sand-to-clay ratio is highly subjective, dependent on quality of clay  
being used.  I cannot offer any suggestion without being able to see/ 
feel/mix your cob.  Kiko Denzer's book "Build Your Own Earth Oven"  
describes how to test samples of cob with various clay/sand ratios,  
as does Cob Cottage's "The Hand Sculpted House".

Although cob construction seems simple and elegant, this example  
underscores the importance of receiving adequate instruction in cob  
mixing to be able to make a strong, consistent mix.  In your case  
failure of the cob is frustrating, but not dangerous.  There are  
examples of cob structures collapsing with fatal consequences.

Ocean Liff-Anderson
Ahimsa Sanctuary
FireWorks Restaurant

On Mar 15, 2008, at 9:00 AM, Muddy Toenails wrote:
> Thanks for your posts.
> So what ratio of sand to clay do you reccomend?
> With much appreciation,
> h.