[papercreters] Re: Papercrete as growing medium

As far as how long they last, I can't help you with anything difinitive there.

They sell "mushroom logs" that are compressed sawdust logs inoculated with mycelium. The shrooms usually cause those to crumble. I suspect one time use is a reasonable expectation.


Since you are looking for extreme low cost, I encourage you to consider square pillars instead of round. That would allow you to use things like scrap wooden pallets as a source of material to make a form. It won't be nearly as strong as a metal pipe, but with an appropriately strong design, perhaps strong enough. Then try to come up with a wooden lever arm to thrust a wooden piston inside that square column form. Playing around with the lever arm might give you enough mechanical advantage to put a few hundred lbs of pressure anyway. Perhaps as much as a 1000 if built extremely strong, but it would need to be build like the U.S.S. Constitution. (A very old and extremely strong wooden naval ship... nicknamed "old ironsides" because of it's strength, but the ship never had iron sides, only wood.)
http://www.history.navy.mil/ussconstitution/history.html


If you built a square wooden form using pallet wood slats laid flat in layers, cross bracing them with each successive layer (predrilling nail holes just enough to keep the wood from splitting) and nailing them down to the previous layer, it should become extremely strong. The trick is to keep everything aligned with other boards standing vertically inside it as guides as you build up the layers. Think along the lines of building a square log cabin using flat boards instead of logs.

With careful disassembly of pallets, and a lot of tedious effort, it's possible to build a very strong form reusing the pallet wood and the nails from the pallet. Zero expense other than time invested.

The tricky part would be to build the piston mechanism and have it all hold together while putting lots of force on it.

I still encourage you to experiment with small scale testing, just to be sure you want to go in this direction. Try a small bucket of paper slurry, drain it, and compress a generous handful in a workshop bench vise. You'll be amazed at how the pulp will transform almost like magic. Just be sure to dry off the vise and wipe it down with oil afterwards to avoid rusting the vise, especially if you borrow a friend's vise and you want to keep them as a friend. :)




--- In papercreters@yahoogroups.com, "prrr.t21@..." <prrr@...> wrote:
>
> 10" x 5' would weigh excessively when saturated, so it will just be kept damp. But one has to allow for misuse, getting caught in torrential rain etc, so its got to survive saturation.
>
> Re the costs of a hydraulic press & high pressure pipe... the aim is for these to be makeable by people that cant come anywhere near affording a bottle jack or pipe. Hence the choice of scrap paper. A wood stick lever is within that budget, but not a pipe mould. This is why I've been looking at a minimum amount of cement. If this goal is truly unachievable, switching to bottle jack & pressure pipe is possible, but it would be a plus to avoid that.
>
> Plant roots will try to break the stuff up. Somehow it needs to survive that - I'm hoping a plastic wrap will handle that. Whatever's chosen will get tested of course.
>
> I was thinking cement could bypass the upfront cost of equipment problem, if the amount used is small & thus cheap. The papercrete could simply be moulded in the plastic film wrap without pressure.
>
> Initial figures suggest the material cost is similar for weak papercrete with scrap plastic wrap versus pulp with proper stretch wrap. The latter also requires equipment, the cost of which is a) prohobitive for most, and b) would increase product price due to amortisation of the equipment cost.
>
> A small scale sample would be a lot easier to make, but would dry out relatively fast creating a watering issue.
>
> Does paper pulp moulder? If so I'm not sure how to stop that.
>
> I've assumed so far that these poles would only be good for one season. Perhaps they could last longer somehow?
>
> thanks for all the input so far.
>
>
>
> --- In papercreters@yahoogroups.com, "JayH" <slurryguy@> wrote:
> >
> > Thanks for the additional info. Your goal is much more clear now.
> >
> > You talk about the need for light weight. I don't see how a 10" diameter 5' high pole will be lightweight when it gets saturated or wicks up hydroponic fluid. The water weight will be far greater than the weight of the paper.
> >
> > I would encourage you to consider not using cement at all. Just make a paper only slurry, drain it on a screen, and COMPRESS it with as much pressure as you can muster into your pole shape. You'll be surprised how strong highly compressed paper pulp will become.
> >
> > Just to be clear, I'm not talking about just pushing on the pulp with your hands to squeeze it with a few pounds of pressure. I'm suggesting using something like a 10 ton hydraulic bottle jack. (They are extremely inexpensive. You may already own one.) If you created a form that could withstand that kind of pressure and compressed damp paper pulp with a few tons of pressure, it may be strong enough for your needs.
> >
> > Almost all of your expense would be in building your high pressure reusable form that will still allow water to drain out of the paper as it gets compressed. I would suggest checking at your local junkyard for steel pipe that is 10" diameter or so, and they trying to build a cap on one end, and a "piston" that can get compressed by a bottle jack into that pipe to squish the paper pulp. The piston need not be a perfect fit, since you'll need to allow water to drain away as the pulp gets compressed.
> >
> > You should almost be able to turn scrap paper back into logs of wood with such a device.
> >
> > Of course, without anything added to the paper, those logs will mold easily and have practically zero tensile strength, particularly when damp.
> >
> > Before investing time and money in the big fancy pipe and piston, I suggest experimenting in a small scale using whatever scraps you have laying around and with whatever jack or other compression device you already have. Then you'll start to get a feel for what compression can really do to damp paper pulp.
> >
> >
> > You may or may not find these thoughts helpful, but perhaps there are some ideas in there that will inspire you to find a solution you like that works for your situation. Feel free to try whatever variations make sense to you.
> >
> > Please post updates and photos as your project progresses.
> >
>




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