I have been curious about papercrete and paper adobe, so I decided to experiment. First I needed a method of making pulp out of scrap paper. I made a blade out of the lid of a tomato sauce can and bolted it on a length of all-thread which I can spin with a drill. This is far from ideal, but works as a first approximation. I am still looking for a sturdier blade, and ideally I will get a more powerful engine than the drill I have.
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Next up, time to pulp some paper. So I gathered up some scrap junk mail and newspaper ads and ripped them a bit and put them in a 5 gallon bucket to soak. After a few hours I pulped them with the drill mixer. This was a bit slow at first until the bigger chunks had been ripped (they kept wrapping around the all-thread and slowly climbing up it and then spinning around and flying off. The mix was getting pretty thick, so I added more water. So far I have been surprised by how much water is required to mix this stuff up. I bet with a more powerful and bigger blade you could make it a bit thicker though. After turning it to pulp, I added a number of little clay clods dug from the ground. I fear it may be rather expansive clay, judging from the cracks where I dug it. After about an hour of soaking, I mixed it all up with a hoe.
I poured some into a cut off section of bucket to mold it, and quickly realized that it was too soupy. So I drained some through a piece of cloth, and then molded some bricks. I also threw some on a tree to test it's plastering abilities. (potential future use). It might be thick enough to drain through screen, which would speed things up a little bit. So far I have determined that the stuff dries very very slowly. After a full day, mostly in the sun, the bricks were dried enough to move, but were still soft on the surface. I stuck a little dried chip into the stove burner, and it did burn, but went out as soon as I removed it from the flame. This was good enough to inspire me to try a project...
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I decided that a cat house would be a suitable small project, so I made a wire frame out of chicken wire (sort of a mini quonset hut). Then I mixed up another batch and drained it somewhat and started splatting it onto and through the wire. My goal is to imbed the mesh completely within the adobe. One bucket appears to be enough to cover about 2 square feet about an inch thick (wet). I am guessing my cat house will require at least 3 buckets worth of goop. So any serious construction would inspire one to make a much bigger mixer. I think I'll do just one batch a day in the hopes that it will dry enough to move the structure in between applications. I also want to test out applying the stuff to horizontal mesh. (It works ok on vertical mesh, at least up a few inches).
It appears the goop is too heavy to support itself with just the chicken wire, but once it is dry, it is quite hard and strong. Also I think I was adding too much clay to some of my earlier batches so that they shrank too much and cracked a lot. (this wasn't a problem with blocks, but is when I was putting it on the mesh. the front of the structure sagged a bit possibly due to getting caught out in a thunderstorm. oops. There were a number of shrinkage cracks, but I just kept adding layers until they were covered up. I also used less clay in later mixes. I managed to make a better blade out of a piece of metal I found. It still is only a small batch process. Something more substantial would be required for serious construction work.
I made one small block with the paper slurry and some sand-mortar mix. This dried very slowly, but didn't shrink much at all. It is very light, but feels fairly weak (like I could squish my fingers into it if I really tried). I haven't tried though, so it might be stronger than it feels.
It is stronger than it appears, but not that strong, and it sucks water up like a sponge, but doesn't fall apart when it gets wet. I made another block with a bit more sand in it. It is heavier and seems to be a bit stronger.
Lately I have been messing around sculpting various small things. This seems to work ok, but the material has very little strength until it dries a bit, so legs or that sort of thing need to be molded separately and attached later or else supported while drying. If you leave a spot too low (not enough material), it can be easily added later, especially when it is 1/2 dry. Small bumps can be smoothed down while it is still wet or wetted and smoothed later. They can also be filed off, although the resulting surface is somewhat fuzzy and needs to be wetted and smoothed to make it look like adjacent areas. I haven't tried painting anything yet, although I presume it would work as long as the paint wasn't too wet. It might be best to paint the entire thing white and then paint over that with other colors. I need to experiment with some sort of waterproofing, although I suppose paint would supply some water resistance.
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