You're right, the water runs out rapidly if your form has drainage, and the mix amount does not affect the dry time. If you mix without enough water then you get chopped paper instead of pulp. If you mix with too much water, you get a lot of runoff and have to move all that water weight. Dry time after draining is a function of temperature, humidity, and air flow. In the summer when it is 105 with 15% humidity and the wind is blowing 35mph, 4" panels dry in a couple of days. In the winter it takes much longer. Our winter in the desert southwest is probably similar to your summer : )
Lately after the mix is ready I sometimes dump it on the ground and let it drain for a few minutes before transferring it into a form. Drained pc is a lot lighter than the stuff right out of the mixer, and if you are making enough for a house it makes a huge difference in labor. In the past I made a table from 1/2" hardware cloth on a 2x4 framework, with half barrels underneath to catch the runoff for reuse. A while back I put half barrels on a stand next to my no-tow mixer and drilled many drain holes in them. I transfer the pulp from the mixer to the drain barrels and let it sit a while. This is a bit stronger than the hardware cloth table, but doesn't drain as fast.
I sometimes pump pc, and that takes a fairly watery mix which drains a lot. It still seems to dry in about the same time as any other pc of the same dimensions.
spaceman
Viglietta, Ben wrote:
Re: Drying Time for Papercrete Blocks Thanks to all for the responses.
Please note that the wood ash is only .5 pounds in the overall 12.5 pounds. We put it in after reading about pozzolanic ash. This ash may have only a small proportion which is pozzolanic but we have observed that the fully dried block is harder and I think somewhat more impervious with the small amount of ash.
As far as water goes, we watched the videos and read stuff by Mike McCord and got the idea that the water is not a measured ingredient. When the papercrete mix is put in place, clear water runs out rapidly and the material settles. So the water in it was excessive to start. Is that how others do it?
We put the material into a form and stood two 2-liter bottles in it to make that block. I am not sure this is an efficient enough process to make enough blocks for a building. But we were trying to get a good result even if it was a small batch. The block looks quite good.
Ben V
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