[Cob] natural building purism, practicality & appropriate technology

[Kristen Davenport Katz]

Interesting.  However, I can say with some certainty that the "consistency"
with a cement mixer is excellent, and it was a well-known cob builder who
studied with even more well-known cob builders who taught me that a cement
mixer is a really good alternative for someone without the time or strength
to mix by hand. We have built two cob structures so far with this, and plan
on more. They are perfect. They are beautiful. I'll send pictures soon. One
of them has been up four years or so and shows zero sign of wear and we
haven't even bothered to plaster it. If I had more time and was 10-20 years
younger, and didn't have twelve jobs, I'd build by hand and use my feet for
mixing. But since I do have 12 jobs , two kids, 10 goats, 5 acres of organic
vegetables, 6 beehives, a mother-in-law who relies on my care, and a husband
who wants some attention periodically, I'm really delighted with the outcome
of mixing cob in a cement mixer. If that makes my cob less authentic, so be
it. Fine with me! I can say that it was EASY to build those structures. I
could have done it by myself, except my brain had a little trouble with the
reciprocal roof.

Kristen

-----Original Message-----
From: coblist-bounces at deatech.com [mailto:coblist-bounces at deatech.com] On
Behalf Of Ivan
Sent: Monday, March 04, 2013 2:12 PM
To: coblist at deatech.com
Subject: Re: [Cob] natural building purism, practicality & appropriate
technology

Hello everyone...

I seldom stay on top of the coblist messages anymore but I happened to check
lately and appreciate the philosophical discussion taking place here in the
last few threads concerning purism and practicality. I feel that many of us
deal with this issue on a daily basis and not just in building
alternatively. I believe a happy medium can be struck but it concerns more
our idea of what constitutes technology than a compromise of values.

Let me explain...even cob uses some basic tools - the tarp, the shovel,
buckets... however we never hear anyone condemning such technologies. We all
draw our lines of purism differently but on the whole, from what I have
experienced I would guess that the majority draw the line of purism when oil
and gas machinery and/or chemical industry supplies come into use and some
draw it at electricity. This is a complicated mix of technologies which has
evolved over 300 years and thus is not as easily distinct as the difference
between modern agriculture and organic foods which really has a pre-chemical
divide to it - pre 1920's (only nearly
100 years ago!!). So, outside of this divide of modern supplies and
techniques there is still an enormous experience for us to draw from
pre-dating modernism. Just as important is our ingenuity and progress made
since that time... and we can pick and choose tools, supplies and techniques
which we feel fit our global sense of purism without having to build
everything with our bare hands!

Today, are we still not pioneers? Currently I am in no position nor have I
the time to investigate further (surviving!) but I want us to remember that
we can use man powered gadgets that will enable us to ease our backs and
also build faster with only the smallest imprint on the web of life.
Technologies such as the waterwheel and windmill have done this for us, it
is what pulleys do (without harnessing the power of animals or dead plant
matter in all its forms), horse drawn threshing machines etc... . There are
many examples but one that I like that that gives greater perspective into
the vision I am having are the cranes that the romans built 2000 years ago;
cranes operated by 2 people (in a wheel not unlike a mouse wheel!) using
counterwieghts to manouever supplies and build with.

These are not technologies that harm us in the short or long term. They make
our lives easier and sometimes even improve with finishing a project faster.
This perhaps would be a happy medium that the masses could adopt? Anyone out
there have experience with such technologies or techniques?

It is evident that such technologies are more complicated than a shovel and
tarp but definitely within our reach! The knowledge of use and how to build
them are small obstacles we as an alternative building community should be
able to master quickly...created and adapted for our needs (in this case cob
mixing) and built locally with very cheap and accessible materials.

Some years ago when planning on building a home I remember trying to find
such existing alternatives (an appropriate mixer) but did not come across
any and read (back then in a book) that cement mixers and rototillers did
not come close to perfecting a mix such as is needed, so I started doodling
a sketch for a new machine to do the job. Before I went much farther with it
we had opted for hempcrete on 3 sides (for speed and insolation in the cold
Quebec winters) and ended up doing cob with windows only on the South facing
first floor (and second floor using strawbale), so building the machine
would have helped us only a little and it would have taken more time overall
for such a small portion of the house (as any new gadget does to iron out
the bugs). So we did the cob portion the old fashioned way... with sweat,
smiles and patience but for any larger project I would reconsider building a
'human assisted cob mixer'.

I will build with cob again - this time in my new unfound home in the
South... but although I am not ready now, if anyone has links to such trials
or real human assisted technology please let me know.

I will also share a bit about the plans I had in case it sparks ingenuity in
any of you. The main principle I had went something like this...

It had two different parts / purposes.
The first was to mix the dry goods... the second to add the water and
eventually the straw.

The first was similar to a hand driven concrete mixer and there were several
methods... the one I prefered was: A frame, hip high with a swivelled head
plate attached and a container to take the dry materials attached to that -
a metal drum from a dryer was the recycled material of choice, with 2 ropes
wrapped around it - one pulled one way... the other the opposite... so one
man could walk one way, then the other spinning and mixing the contents
easily...

This was then supposed to be dumped into the second contraption... 
either a shallow narrow pit dug into the ground or made with straw bales and
a tarp.
This had a frame above it with a pulley attached to wieghts (some medium
sized rocks), that would be pulled by a rope and left to drop onto the
narrow channel pounding the cob together. I pictured this more like the
kneading of bread... the pounding weights would bind the clay, sand and
straw tightly...I can't recall how I thought about scooping it out to turn
over though? Perhaps it was just that the tarp could be flipped as in the
common fashion of cob making...hmm.

Another method for the second contraption (again better with two people) was
a type of double rolling pin design... where the contents would be squeezed
through them (not sure at this point about the straw?) - loaded from the top
and reloaded until the perfect consistency. The idea to turn the pins was a
bicycle frame... where if needed the the body of the rider could force
weight on the gears... but I think that as long as there was someone filling
and refilling (throwing globs with their
hands) that the weight of the material would help force itself through the
pins when turned.

Of course... one could take all these ideas or other design and attach it to
a waterwheel and you have mechanization!

Well - just some food for thought.

Have a wonderful week!

In solidarity
Ivan Tattoli


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