Making of a Cob Bench



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History of the Bench




Soil Analysis



Strength of the Cob


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The Materials






There are three main materials that you need to make cob: sand, clay, and fiber (in my case, straw).  So, for my project, I had to make sure to have all these materials, plus a few others.  This page will walk you through each material.  First... 







The sand that I used to for the bench came from Granite Construction which is only a 5-10 minute drive from HSU.  At the site, a dump truck poured a large quantity o sand into my friend's pickup truck.  A whole truck load came to only $20.  It should also be noted that one shouldn't use beach sand for cob construction; it is better to use river sand.  This is because beach sand is too smooth.  The sand used in cob construction should be rough.  Rougher sand allows for the sand to interlock  and hold together, which adds to structural strength.   Below are pictures of Granite Construction.     

















Some of the clay that was used came from the CCAT grounds.  However, most of the clay that I used came from Kiva, an HSU student who also used the clay to build a green house in her ENGR 305 class in Spring 2004.  The clay that came from the CCAT ground had to be checked to see if the soil had a good enough clay content.  We determine this by using the "E-Z" soil analysis test



The straw that was used came from "The Farm Store," off the 101 just north of Eureka.  The straw was kept at CCAT in a push cart with a tarp over it.  This tarp would keep the straw dry so rain wouldn't be constantly soaking it.  This would prevent the straw from rotting and thus becoming unfit to use for making cob, and starting to smell.



 Lastly, I went to Arcata Recycling and bought glass that I would use to decorate the bench.  The Center donated beautifully colored dark and light blues bottles, and I bought 3 clear textured dishes which cost $5.  Below are pictures of the recycling facility.




Below you can see pictures of some of the glass that was incorporated into the bench, as well as seashells that were donated by the Oceanography Department. 






Natalie, a class mate and natural building group member, was also kind enough to give me piece of broken mirror which will also be very beautiful for decorating the bench.



Not only do you need materials, but you also need other supplies.  Supplies include graters, sifters, tarps, shovels, spades, wheelbarrows, buckets, and a cobber's thumb.  Don't forget an enthusiastic attitude, and maybe a few friends to help out. 


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