Cob Off Topic: A Little About FC

[Mary S. Miller]

Well, I've been playing with fibrous cement for a little over a month now.
It's interesting stuff.

My "recipe" is:

2lbs dry weight paper (mostly newspaper)
6lbs dry builders sand (any sand will do, even sifted road base)
1lb cement (approx)
Water, lots of it
Add the paper first into a big bucket or tub with enough water to cover 3-4
inches, chop it up until it looks like a gray mass not paper and then add
the rest continueing to mix

Actually, I've been using volume on the sand and cement. A small plastic
bowl that I have weighed only one time with the ingrediants in it. The paper
is weighed on a small digital scale and soaked as long as possible.  But
after making a "wall" of fibrous cement bricks, 2' x 8" x 8' (yep, feet), I
would say that if you're not real exact with your measurments, it won't
matter. In the long run with a home or building, the cost of the cement will
make a difference though in the bottom line.

The molds that I've used are made from 1 x 3 treated pine. Just box forms.
Nothing fancy.  Before I make any building though, I'll make some new forms
using 1 x 6's.  The 2lb paper batch will make 3.33 of the 3" x 8" x 12"
bricks. The mixture settles quite a bit so if you want a full form when it's
dry, you gotta keep adding as it settles/drains down.

The strength on this stuff is pretty good. It does tend to "crumble" a
little but when it's put up into a wall, it's real stable. I've walked and
climbed on it a lot.

There's a book you can order and a quarterly magazine that has much more
information about fibrous cement.  If you're interested in these, there is a
web site for the magazine, "Earth Quarterly."  The web browsers found it w/o
a problem. I would very highly suggest getting the magazine anyway.  The
book has lots of photos and more information in it. And that guy, Mike
McCain has built complete houses with this stuff. No guessing for him!

Anyway, the number one problem I've run up against is mixing the stuff.  At
first I used a gasoline weed-eater with the guard removed. But now I'm
working with a small machine shop to make an electric mixer using a 2hp
electric motor on top of a decapitated plastic barrel. My poor weed-eater is
almost dead and I didn't even build one whole wall.

Don't know if this well help any but good luck.

Take care everyone,
Mary