Bob,
Thank you for a very interesting explanation for stuccoing a vessel. The
Native pottery makers in the Peninsular Mountains of Alta and Baja California
do not apply stucco to any vessels, cooking or otherwise. We find the
stucco coatings on vessels associated with extinct Lake Cahuilla, which stood
from A.D. 900-1600 and could have been present when Hernan de Alarcon sailed
a Spanish ship up the Lower Colorado River. The stucco coated pottery is
quite rare, based on a collection of 12,000 sherds recovered from around the
lake. Stucco coated pottery is also found at locations along the Lower
Colorado River, but I am not familiar with the details. Of course, an exterior
stucco could have disintegrated off the residual clay pottery of the
mountains and there might be some properties of the sedimentary clays that
caused the stucco to survive longer out in the deserts. I greatly appreciate
your comments.
Ron May
Legacy 106, Inc.
In a message dated 7/3/2009 4:01:02 P.M. Pacific Daylight Time,
[log in to unmask] writes:
Ron,
Roughening of the surface, whether by stuccoing, indenting, brushing or
any
other method, increases the amount of surface area available to serve as a
"heat exchanger" ... additionally, a roughened surface causes turbulent
currents (in the heated air streaming by the exterior) on the surface,
which
do not necessarily increase the coefficient of heat transfer (efficiency)
of
the surface, but does tend to "regulate" it (slows down abrupt changes in
temperature) within a more moderate amd predictable range (that is, the
pot
is not so sensistive to its alingment over the heat source/fire ...
consequeently, doing away with hot and cold spots ... that, incidentally
gives another decided advantage, making the pot less susceptible to
breakage
from the shocks of localized hot & cold spots ... "chunky" temper of the
right kind and size also conferring these advantages).
Consequently, as a general rule (across all cultures that I am familiar
with
in Northern America), the cooking pots almost always have roughened (or at
least non-smoothed, non-polished) exterior surfaces.
Bob Skiles
----- Original Message -----
From: "Ron May" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, July 03, 2009 4:12 PM
Subject: Re: Temper
> In addition to mica to control heat, some potters "stuccoed" the exterior
> of pots with clay to control heat. I have examined stuccoed pottery, but
> really do not understand how this helps in heating. Any ideas?
>
> Ron May
> Legacy 106, Inc.
>
>
> In a message dated 7/3/2009 3:14:07 A.M. Pacific Daylight Time,
> [log in to unmask] writes:
>
> Mica could enter the pot as temper (with quartz sand) as micaceous
> sandstones are not uncommon at least in Europe.
>
> I came across an interesting example recently from a kiln in Swansea, S
> Wales. it produced pots which appear t be late C15/early c16 in date
> paralleling similar vessels from the Cotswolds (Minety area) suggesting
> a source for the potter. The Cotswold pots are tempered with oolitic
> limestone but the Swansea pots appear to have been tempered with an
> oolitic sand probably from a beach along the nearby Gower peninsula. The
> pots re unknown from consumer deposits so it looks as if the kiln was
> short-lived- possibly not much pot being used in this period which
seems
> to be dominated by English and Continental imports.
>
> paul
>
>
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