[Cob] Cob: Paper clay

[Raduazo at aol.com]

In a message dated 5/21/2005 8:38:37 PM Eastern Standard Time,  
ap615 at hotmail.com writes:

The  person who developed the stuff being sold does have a patent.  That may, 
 
mostly, cover the process by which she made it not turn sour in the vat  and 
make it salable.  There's been an awful lot of   paper-whatever (padobe, for 
one) or even whatever-crete, not all of which  has con-crete in it, IIRC.




The patent relates to a composition suitable for firing, and if you made  
roofing tiles with paper cob and fired them you would be infringing the patent.  
The stuff that I make is not suitable for firing. I do not go to great length 
to  break up the paper into individual fibers. I do not go to great lengths to 
 remove all clumps of paper from the mix, and my waterproofing is done by  
applying boiled linseed oil and then possibly urethane if you want a real hard  
nonporous finish. (Possibly not a good idea for a wall that must breath.) I  
think that I use a lot more paper than the patent. I have a picture of my  
batching plant with all the material that went into one batch. The batches seem  
to bond well when boning wet plaster to dry cob or to dry plaster. 
    The children's playhouse at Green Spring Gardens  Park has had about 80 
inches of rain with no roof. The paper plaster appears to  be out performing 
lime plaster.
    I have not done any research on the optimal mixes.  If there is anyone 
who wants to do another science fair project this would be a  good one to try. 
    By the way: In the earth floor science fair  project Abby found that 
boiled linseed oil out performed all other  materials tested under impact. 
Probably because it penetrated deeper into the  earth floor material. (She tested 
impact resistance by dropping the  head of a ball-peen hammer 5 1/2 feet through 
a plastic tube on the test  surfaces.)
    More sand was better for impact resistance and  there was no measurable 
difference between paper and shredded straw as the  reinforcing material.
    All paper (no sand in mix) tended to get  moldy. All straw (also no sand) 
did not. 
    There was no structural reason to put lots of paper  in a floor as small 
amounts of fiber and lots of sand seemed to give the best  results.
Ed