I've just started using my shop press to make blocks, don't have any photos yet but the set up looks very hopefull. the first block I made I used:
- 4 gals of just slightly wet office paper/cardboard pulp,
- 2 gal of dry cement and
- 2 gal dry sand (just local stuff)
After pressing all the water out and removing the form, I went to pick up the 8"hx16"lx12"w block and could hardly lift it. It took four days to completely dry and the finish weight was 68 lbs. Whyyyyy too heavy to work with, so I cut the batch in half:
- 2 gal sighlty wet office paper/cardboard pulp
- 1 gal dry cement, and
- 1 gal dry local sand.
After pressing out the water from the 3.5"hx12"wx16"l block , it dried in about 3 days and the finish weight was 28 lbs. Still heaver than I wanted but workable, I'm going to increase the:
- cardboard/paper pulp to about: 4 gals and
- cut the cement to 1/2 gal and
- the sand to 1/2 gal and see what that turns out.
I really think that pressing them is the quick way to go if you want to start laying right away. The out put is a lot less that the super wet slurry but the working time is considerably less, even if they are not completely dry, in two days you can handle them and probably lay them and they can dry in the wall. The first two had such a small amount of shrinkage that I could not even tell that it shrunk at all.
Bob
--- In papercreters@yahoogroups.com, "donald1miller" <donald1miller@...> wrote:
Having made blocks out of both newspaper and heavy cardboard, I fail to see the aversion most people have to using cardboard as pulp. If soaked thoroughly it pulps well in a McCain style tow mixer, just takes longer than newprint. The fibers are very strong in cardboard and the pieces are somewhat bigger than pulp made with newspapers. This seems to me that they would bind the blocks better than smaller pieces of the newspaper pulp. It is analagous to the difference between particle board and OSB board, or waferwood panels as they are called in some quarters. Particle board being made of small pieces of wood fiber is not nearly as strong as OSB which is made from bigger chunks of wood. Maybe this doesn't translate over to PC the same way, but I think it would. I made a batch of blocks with just cardboard pulp and they are very strong even without any clay or cement to act as binder.
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