Ron Roy on tue 2 nov 04
Hi Steve,
I have noticed the lack of plasticity in Red Art - is this the result of
the low PH? That would seem to make sense to me.
This is great info on one of our basic North American clays - you must have
more on other clays - I for one would like to know more.
I have done dilatometer tests on Gold Art, Salt Lick and Roseville - very
strange - no cristobalite at cone 10 - every other raw clay I have measured
has at least some - and most have a lot. Got any idea why?
Thanks - RR
>Since your red clay is probably made with Cedar Heights Redart clay, and I
>am intimately familiar with that clay from working there many years, let
>me just elaborate a bit on what has already been written.
>
>First, there is nothing exotic at all about Redart. 100% natural.
>Deposit is a sedimentary compacted siltstone/clay of about 300 million
>years plus. Simply dried and pulverized. Practically a rock in its
>natural state, and pretty much biologically and chemically inert. But
>compared to a lot of clays that don't, it has a pH approaching neutral,
>somewhere in the low sevens usually. This is probably the key to your
>problem, and those who have suggested a mold problem are probably right on
>the money. A stockpile of Redart clay will grow grass and weeds. A
>stockpile of practically any Ohio fireclay will not grow a single weed.
>Not a one. pH is much too low due to decomposing pyrites producing acid.
>That is why old coal/clay pits in Ohio look like a disaster site because
>the acid keeps anything from growing. Just like a mushroom is rather
>particular about its growth environment, I assume other spore type animals
>may be as well. But my guess is that your particluar clay body is
>
> a very fertile environment for a specific mold you are allergic to.
>Whether you could change the pH with vinegar or another acid I don't know,
>but possibly. May be some other inert mold growth inhibitors that could
>be added.
>
>Good luck.
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
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