Thanks for that great response!
I've just worked with cement making artwork for outside mostly. I'd seen bowls that my cement mentor had made from paper pulp and had gotten him to show me how to make paper pulp. All my stuff is fairly small. I just bought a trash can and tore some newspaper up in it and covered it with water - enough water so that I could periodically stir it easily with a broom handle. I covered it and added water as needed to be able to stir it easily. I also added clorox periodically to keep the smell down. Then when it had turned to pulp I just took out handfuls and began squeezing the water out and patted it around the bowl that I'd placed face down, to use as a form, on a piece of wood. And I just let it sit out in the sun and dry for days. So I get that part about getting the paper to pulp. -glad to hear about thinking of it as a wood product.
Anyway, I'd like to move on to making a papercrete piece and have a mold that I'm thinking of using. It's about 2'x3'. So the water would have to evaporate and wouldn't be able to drain off. BTW, I did have clumping with the bowl and would like to avoid that. Also, I usually make hanging pieces and have usually placed eye hooks attached to chicken wire or wire mesh in my cement pieces. I don't know how that will work with PC. - just kind of thinking out loud. Let me know if anyone has made anything besides houses and bricks.
Oh, the other thing is that when I make bricks they're usually decorative so I'm thinking I'd want to do a similar PC thing -- not bricks though. If I made a wall hanging I might want to put glass or other objects in the bottom of the mold or if I did a face up piece I might want to put different objects - tile or whatever - into the piece. I'm all ears if anyone has experience to share. And I'll experiment myself actually. I think that's very good advice.
Thanks, Carrol
slurryguy <slurryguy@yahoo.com> wrote:
A.J.
Several factors to consider here. Some of them you may already know:
Papercrete is a wood product, not a masonry product. Trying to apply
the rules we all take for granted about concrete to wood products
simply won't work.
The reasons this is the case are not completely understood, but
overwheling subjective experience related by every experienced
papercrete builder I know of indicates that it takes a HUGE amount of
water to get a papercrete mix too wet. The key to understanding this
is to think about the microscopic structure of papercrete and how it
is radically different from mortar or concrete. Papercrete is a
tangled web of matted fibers, while concrete is a solid mass of
various particles bonded together.
The ideal concrete mix will contain exactly the correct amount of
water to hydrate every cement particle with no extra water to hang
around as tiny droplets encased inside. When concrete is poured, it
never really "dries" it "cures". That curing is a chemical process
that utilizes the water in the mix in that chemical reaction. Water
does not drain out of concrete or evaporate out, it remains bonded
inside the material. If too much water is used in concrete it still
gets trapped inside the material and weakens it.
This contrasts radically with papercrete.
Papercrete is inherintly porous. Water drains out, then evaporates
out. The vast majority of water used in making papercrete goes
away. Some water does bond with the cement (or other chemically
active ingredients that might get used). Another interesting
characteristic of papercrete is that the moisture level inside fully
cured and dried papercrete varies over time and weather. Just like
wood! Wood expands and contracts with moisture levels. So does
papercrete. A previous post discusses the various forms of water in
papercrete in detail:
http://groups.yahoo.com/ group/papercrete rs/message/ 115
Anyone with experience with concrete will NEED to have a fundemental
shift in thinking when they start working with papercrete. At first
it will seem illogical. It may seem like it can't possibly work.
MAKE SOME ANYWAY. See it all the way through to the end and see what
DRY papercrete is like. That is the single most important thing to
help someone understand it. MAKE IT. You simply must see it to
start to understand. You don't have to try to build a house. Just
mix up ONE BUCKET of papercrete and it will help you tremendously in
understanding what is going on.
Most concrete workers are used to seeing concrete firmly setup after
a day. They realize that the full strength won't occur for 28 days,
but work can progress because concrete will have significant (but not
full) strength after only 1 day. Papercrete will have almost no
strength after 1 day. Papercrete gains strength gradually as it
dries over time not as the cement in it chemcially cures. That which
seems like a grey spongy ooze after 1 day will dramatically change in
a few weeks into a light and remarkably durable material.
Now that I've discussed the background..... on to answering your
questions:
Most people don't discuss the amount of water they use, and I wish
they would include that in their discussions more often. Let me toss
out a reasonable example. A typical 200 gallon tow mixer may use
around 100 lbs of paper and 100 lbs of cement. The mixer usually
isn't filled to the very brim with water, so it's likely that about
150 gallons of water might be used. Since a pint is a pound the
world around (a very good but not exact approximation, let's not
start THAT discussion again) that works out to about 1200 lbs of
water.
12 times as much water as cement or paper? Have Papercreters lost
their minds????????? That's an insane FLOOD in concrete circles.
In actuality it is very resonable in working with papercrete. That
amount of water is REQUIRED to adequeatly pulp the paper. That is
KEY. Papercrete works best when the fibers are pulped down
completely. It is important to remember that ALMOST ALL of that
water will disappear from the final product. A smart and thrifty
Papercreter will capture the water that drains off the wet slurry
recycle that runoff water into the next batch of papercrete.
How can this work? It's all in the fibers. What is a coffee filter
made from? (Paper). The paper fibers in the papercrete act like an
internal filter and filter the runoff water. The water that drains
out of papercrete drains mostly clear, leaving almost all of the
cement particles in the papercrete.
The large quntity of water also seems to have an effect in how well
the slurry matts down as it gets poured. If a dry slurry is poured
it will come out lumpy and have lots of gaps and air pockets. This
weakens the product. A very wet slurry will pour out nice and smooth
and dense when drained.
All of this said, you raise many important points, A.J.
How do we all measure?
When making large amounts of papercrete and trying to get a lot
built, we proably will all measure by eye. It's the most efficient
way to go. However, HOPEFULLY, each of us will take the time ONE
TIME for ONE BATCH to carefully measure precisely how much of various
ingredients for each different recipe we use so that we can
accurately tell everyone else what we are doing. This is especially
important for entering data into the recipe database.
While I'm confident that a nice soupy slurry produces the best
papercrete, we should endeavor to PROVE that this is the case
EMPERICALLY. Ideally we will be conducting our own informal testing
to demonstrate exactly the case. Official standardized testing of
the important key recipies will then follow.
--- In papercreters@yahoogroups. , "a.j. welmers" <pcmixdb@...com >
wrote:
>
> In the discussions and recipes I am researching I do not see a lot
of
> information about the water that is used. Without any experience in
> using PC, I know in my daily constructionwork with concrete that the
> amount of water and the impurities in water are important factors
for
> the quality of the mix and I suppose that that also counts for PC.
> Is there somebody in the PC community that can shed some light on
this
> topics?
> How do you measure the amount of water in a mix
> [eyeball / by volume / by weight / just guessing / ....]
> When do you add water?
> [start with water and add all the components / start with wetting
the
> paper and later add more water / have no particular following
order / ...]
> What water do you use?
> [Drinking water / water from a pond / ....]
>
> In the article Concrete Basics that you can find at
> http://www.cement.org/basics/ concretebasics_ concretebasics. asp
> I read=>
>
> A properly designed concrete mixture will possess the desired
> workability for the fresh concrete and the required durability and
> strength for the hardened concrete. Typically, a mix is about 10 to
15
> percent cement, 60 to 75 percent aggregate and 15 to 20 percent
water.
>
> The water-cement ratio is the weight of the mixing water divided by
> the weight of the cement. High-quality concrete is produced by
> lowering the water-cement ratio as much as possible without
> sacrificing the workability of fresh concrete. Generally, using less
> water produces a higher quality concrete provided the concrete is
> properly placed, consolidated, and cured.
>
> Excessive impurities in mixing water not only may affect setting
time
> and concrete strength, but also may cause efflorescence, staining,
> corrosion of reinforcement, volume instability, and reduced
> durability. Specifications usually set limits on chlorides,
sulfates,
> alkalis, and solids in mixing water unless tests can be performed to
> determine the effect the impurity has on various properties.
>
> Besides the water content it states=>
> A continuous gradation of particle sizes is desirable for efficient
> use of the paste.
>
> => Should we use other materials besides paper and sand with a
bigger
> particle size in a PC mix?
> => What would be usefull = light / strong / cheap / easy to get.
>
> grtn
> recipe researcher
>
Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news, photos & more. __._,_.___
Your email settings: Individual Email|Traditional
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___
