[Cob] How warm must it be to work?

[Joseph R Dupont]

What is the deal with kitty litter. Is it clay or not?
If it is could you mix it with paperpulp and  make some kind of adobe?

On Mon, 25 Oct 2004 11:02:38 -0700 (PDT) "Shannon C. Dealy"
<dealy at deatech.com> writes:
> On Sat, 23 Oct 2004, Amanda Peck wrote:
> 
> [snip]
> > I don't think that cob, or pure clay/sand or even 
> clay/sand/perlite mixtures
> > "set" the way that lime or concrete does.  So the problem is 
> freezing while
> > it's still too wet not to get ice crystals extruding an inch up 
> from the
> > clay the way I vividly remember from my red clay childhood.
> 
> This is essentially correct, when a cob type mix freezes while 
> still
> significantly wet, it puffs up like popcorn from the expansion of 
> the
> ice crystals and loses integrity.  I don't know the specifics of 
> your
> design or mixes, but for many ovens, the simplest thing is to build 
> a
> small fire in them to dry them out, this can however have a down 
> side if
> your mix shrinks to much the oven will crack (potentially in many 
> places).
> Kiko once made an miniature oven in two hours  for me to use in a 
> display
> at a local festival (dried it by firing it) it did crack, but was 
> still
> good enough for our needs.  Of course doing it this fast is not the 
> best
> approach (we were both to busy to spend any real time on the oven), 
> but
> for a larger oven and a smaller fire, you may find the results to be 
> a
> reasonable trade off.  Another (safer) way to dry it faster is to 
> just put
> one or two fans near it, but even this can crack a drying mix if it 
> dries
> to quickly.  Cracking is caused in part by uneven drying -- one 
> section
> dries and gets hard while an adjoining area is still soft and 
> shrinking,
> results in them pulling apart, since the hard area can't move with 
> the
> section that is still drying/shrinking.
> 
> >
> > Or it's too cold to mix barefoot.
> [snip]
> 
> As one of the few people dumb enough to build with cob in winter in 
> a
> moderately cold and very wet climate, it's only to cold to mix if 
> the
> mud cracks when you stomp on it :-)
> 
> 
> Shannon C. Dealy      |               DeaTech Research Inc.
> dealy at deatech.com     |          - Custom Software Development -
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