pdp1@EARTHLINK.NET on sun 28 may 06
Hi Vince,
I wonder why manufacturers of Pug Mills do not
make the main box out of Gunmetal or some kin of
Bronze?
The relative ease of the foundry's efforts, the
lower melting point than Cast Iron, and the
tendency to fill the mould more nicely, would all
offset the insignificant increse in cost of the
material itself, with savings and then some, for
the cost of making the Castings and machining them
and so on...
As well, there would be none of these kinds of
problems...
Whatchathink...?
Phil
Las Vegas
----- Original Message -----
From: "Vince Pitelka"
> Jennifer -
> Porcelain is fine with aluminum and stainless
steel pugmill barrels.
> Porcelain and whiteware bodies don't work with
mild steel pugmill barrels,
> and the older bluebirds (like the one that Kelly
so brilliantly resurrected)
> are mild steel - that refers to the standard
ordinary steel used in
> fabrication - the stuff that rusts.
>
> I have a mild steel Harry Davis pugmill that I
built 20 years ago, and when
> I was making pots full-time in Northern
California I tried to do porcelain
> in the pugmill. If I was reprocessing a batch
of scrap and then cleaning
> out the mill right away it was no problem, but
if I left the porcelain in
> the mill for any duration of the time, the
porcelain that was in direct
> contact with the mild steel barrel, shaft,
blades, and helixes would go some
> sort of chemical reaction with the steel and
would turn blue-gray and become
> rock-hard. Chunks of this material would come
loose, contaminating the
> clay enough to make it unuseable. Also, the
hard layer inside the barrel
> would eliminate the blade clearance that is
necessary to make the mill work
> properly, so the whole thing would start to bog
down. At the time I didn't
> really have a strong commitment to porcelain -
most of my work was done with
> the venerable Rod's Bod, originally a Westwood
body, now sold by Laguna. I
> replaced the porcelain with Westwood Danish
White with sand, and didn't have
> any further problems.
>
> If you just make sure that the barrel is
aluminum or stainless steel and all
> the other clay-contact parts are stainless
steel, you will have no problem.
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft, Tennessee
Technological University
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