Interesting.
I've never tried to measure absorption or the drying time after
papercrete gets rewetted.
Your post reminded me of some anecdotal incidents where I've
accidentally rewetted papercrete or rewetted it for strength testing
of wet papercrete. My subjective memory parallels your experience.
My subjective experience also suggests that the higher the paper
content in a recipe the more water it will tend to absorb and the
longer it will take to redry. This seems logical and inline with
your analysis.
Great observations. Thanks.
--- In papercreters@yahoogroups.com, "mdumiller" <mdmiller1@...>
wrote:
>
> My absorption tests of simple fully-cured papercrete sample show a
> 166% weight gain with a 60 minute submersion in water. All of this
> absorbed water evaporated within 8 hours (while sitting in front of
a
> fan), and the papercrete is back to its original weight. Now, this
> was a big surprise to me, I figured it would take days again for the
> papercrete dry out. What this tells me, I think, is that the paper
is
> fairly well encapsulated, and the fibers are not absorbing much
water,
> that the water has wicked into the pores -- not the paper fiber
itself
> (which is the fuel source for the glow). Thus, the paper fiber
> doesn't absorb much post-manufacture. So you might be able to skip
> the glycol, PC sucks up pretty good on its own, different from a
solid
> piece of wood that needs a carrier vehicle, organic or inorganic, to
> promote absorption.
>
> BUT, the problem with surface post-manuf. applications is that the
> core of the material might remain untreated (depending upon its
> thickness). Nasty stuff like electrical short circuiting occurs in
> the core, where you need fire glow-suppressant the most. Well,
maybe
> not the most, the surface is important, too. I guess they're both
> crucial. The ideal IMHO is to get the PC prepared properly at the
mix
> stage, then you're certain it will be successful. Scraping away the
> char from the sample test I showed pictures of, I was amazed that
1/8"
> down there was good solid papercrete that seemed totally unfazed by
> the 2000 degree torch. A perfect circle 1 1/2" in diameter and
1/8" deep.
>
> I have a simple-papercrete sample, fully-cured, that has been
> saturated with a given amount of boric acid/water mix. I made this
> yesterday. Within a few seconds the sample totally absorbed the
> liquid mix, to about 3/4" deep on the sample. I'll find some time
to
> check it out and share the find. Now, let's say you already have a
PC
> structure and want to post-treat for fire, at least on the
surface .
> Then spraying with the mix might be the only solution and better
than
> nothing.
>
> What's the hitch? Finding a cheap source of boric acid.
>
>
>
> --- In papercreters@yahoogroups.com, "Ernie Phelps" <eepjr24@>
wrote:
> >
> > --- In papercreters@yahoogroups.com, "mdumiller" <mdmiller1@>
wrote:
> > > This proof of concept is important for the code portion of this
> > > work, since PC can't be used in a many construction situations
if
> > > there is no simple (cheap) way to totally fireproof it.
> >
> > Very interesting. I am wondering if the same would hold true if
you
> > were to form the block normally, then soak it afterward in a Bora-
core
> > type mixture (boric acid, borac and anti-freeze, properly
dissolved).
> > This is know to penetrate several inches into dry wood, even, so
it
> > should work.
> >
> > - Ernie
> >
>
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