Here is a link to Paul's photos. As usual, you will need to be logged in with your YahooID you registered on Papercreters to be able to view the photos. (That's Yahoo's rules, not mine.)
http://groups.yahoo.com/group/papercreters/photos/album/701148754/pic/list
The length of wait time required before removing a mold from papercrete depends on the type of mold used, and the papercrete recipe.
If someone built a mold that has no bottom, and just set the mold on the ground, or sand, or screen, then you can remove that mold as soon as the papercrete has finished draining. Once gravity has pulled away whatever excess runoff water was in the papercrete mix, you can carefully remove the mold, as long as you can do it without disturbing the damp papercrete. With most papercrete recipes this can be done within 15-30 minutes of the initial pour. Your mileage may vary. Bottomless molds are typical for making papercrete construction blocks. This appears to be the type of mold Paul has used.
If the mold has a bottom, requiring you to invert the mold, or break the mold apart, or something like that to get the papercrete out, you'll need to wait until the papercrete is nearly completely set before removing the mold. This type of mold is more common with artistic papercrete projects, where the mold has some kind of relief or design that someone wants the papercrete assume the shape of. Usually it will be best to simply wait for the papercrete to dry sufficiently that it shrinks away on its own from a mold with a bottom.
The amount of time required before you can move, turn, or otherwise handle a papercrete block varies dramatically depending on weather conditions and recipe. The "real world practical" answer is, "USE YOUR JUDGMENT." Think of this as baking a cake and you're testing for doneness. Gently tap on the papercrete. Is the upper surface getting hard yet? If it is still soft, leave the papercrete to dry some more. Poke your finger on the side of the block near the ground. Does the papercrete dent easily, or crumble? If so, let it dry longer before moving or turning.
Keep in mind that the bigger the size of the blocks, the longer it takes them to dry.
Paul has made some extremely long blocks. From the photos, they appear at least 10 long. Blocks that are that long will need to be nearly completely dry before turning if you want them to hold together in once piece, especially if you want to avoid a lot of cracking.
In 108 degree Mojave Desert conditions, Paul's papercrete will dry a lot faster than most people experience elsewhere. In the end, there is only one way to find out if someone's papercrete is ready to be moved or turned. They just have to bite the bullet and try to move one of their blocks and see what happens. If it falls apart, they didn't wait long enough or their recipe was so weak that even after it dried, the papercrete wouldn't hold together. Make appropriate changes for your next try. Keep trying, and you'll find what works in your situation.
--- In papercreters@yahoogroups.com, "paul_vanderwerf" <paul_vanderwerf@...> wrote:
>
> Hi,
>
> Well, I've got plenty of shredded paper, so I've mixed up my first batch of papercrete.
>
> I attached a group of pictures in the photos (the group is called Mojave Desert Trials).
>
> Please let me know how I can do this better...
>
> (1) 55 gallon drum of shredded paper soaked in water for 24 hours.
> (2) Mix with drill.
> (2) Remove 15 gallons paper and add 15 gallons sand dune sand.
> (3) Mix with drill.
> (4) Fill 5 gallon bucket with mixture and add 0.5 gallon portland cement
> (5) Mix with drill.
> (6) Place in 12' metal mold. (Takes four 5 gallon buckets.
>
> I included the first 30" mold I made.
>
> The papecrete is drying in 108 degree temperatures.
>
> Q1: How long should I wait before removing from the mold.
>
> NOTE: The 30 inch prototype was removed a little after an hour.
> The first 12' mold was removed a little longer than a day.
>
> Q2: How long should I let dry before moving?
>
>
> Thanks!
>
> - Papercrete Paul
>
> Mojave Desert near Trona, CA
>
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Sunday, July 7, 2013
[papercreters] Re: Papercrete - Mojave Desert Trials
