08-16-2017, 10:32 PM
papercrete seminar report
Papercrete is a construction material which consists of re-pulped paper fiber with Portland cement or clay and/or other soil added. First patented in 1928, it was revived during the 1980s. Although perceived as an environmentally friendly material due to the significant recycled content, this is offset by the presence of cement. The material lacks standardisation, and proper use therefore requires care and experience. Eric Patterson and Mike McCain, who have been credited with independently "inventing" papercrete (they called it "padobe" and "fibrous cement"), have both contributed considerably to research into machinery to make it and ways of using it for building
Papercrete is a fairly new ingredient in the natural building world. It is basically re-pulped paper fiber with portland cement or clay and/or other dirt added. When cement is added, this material is not as "green" as would be ideal, but the relatively small amount of cement is perhaps a reasonable tradeoff for what papercrete can offer. I have had a fair amount of experience with this stuff, and I would say that is has some remarkable properties. Care must be taken to utilize it properly, or you could be courting disaster. I am acquainted with both Eric Patterson and Mike McCain, who independently "invented" papercrete (they called it "padobe" and "fibrous cement") and they have both contributed considerably to the machinery to make it and the ways of using it for building.
The paper to be used can come from a variety of sources and is usually free. I've used newspaper, junk mail, magazines, books, etc., which I get from our local dump or from the waste bin at our post office. Depending on the type of mixer that is used to make pulp out of it, the paper might be soaked in water beforehand or not. My first mixer used a small electric motor mounted directly to a shaft with a couple of four inch square blades on it, rather like a milk shake maker. This shaft was suspended in a plastic 55 gallon drum where the mixing took place. After a year of making small batches with this, I graduated to a "tow mixer" designed by Mike McCain. I consider this to be the Cadillac of mixers because using it is so easy and fast.
It is basically a trailer made from the rear end of a car, with the part that would attach to the drive shaft sticking upward and a lawn mower blade attached to it. The blade is surrounded by a large stock watering tank where the mixing occurs. There is a baffle on the side of the tank to force the slurry back into the blade as it circulates. With this mixer (which I tow behind my Volvo station wagon) I can make three or four wheel barrows full of thick papercrete in about twenty minutes. I simply fill the tank nearly full of water, add about one wheel barrow full of dry paper, one sack of portland cement, and perhaps some sand, depending on how I plan to use the mix. Then I drive slowly around the block, back over a drain box with 1/8 inch mesh on the bottom, and dump the slurry into the box via a drain hole in the bottom of the tank. After about a half hour of draining the excess water from the slurry, the papercrete is like soft, workable clay, but not nearly as messy. This is the material that I used to plaster both the inside and outside of my earthbag house.