Roger Graham on sun 13 oct 02
For Primalmommy, and any others who'd like to try it: Yes, spin casting on
the wheel head works for me. Only using hot lead, mind you, not aluminium or
brass.
How this all began: I had an interest in sandblasted designs on pots. Throw
a pot in white clay. Coat it with coloured slip, say iron oxide brown or
cobalt blue. Let it dry completely. Clip on a suitable stencil, then gently
sandblast the green unfired pot to remove the coloured slip around the
stencil. Very pleasing... but a bit ho-hum with simple stencil shapes. Much
more interesting if the stencils have a bit more detail.
What to make the stencils out of ? Paper isn't a big success. Lifts off in
the blast of air. Sheet lead is excellent. Cut it with scissors. Clip it on
somehow. Being easily bent and malleable, lead holds its shape when pressed
against the curved pot. Very detailed shapes needed lots of care with
scissors, or assembly piece by piece with copper wire and solder. Which
brings me to the centrifugal casting idea.
In brief, the detailed design is carved into the flat surface of a plaster
slab. Clamped face-down against a smooth bat on the wheel head, with a
suitable hole at the centre where hot lead is to be poured in. Spin fast,
pour in lead.
There's a LOT more detail if anybody's interested. Needs pictures, so make
contact off list if you feel adventurous. I'd enjoy putting together a
picture essay and a page or two of description.
Roger Graham, near Gerringong, Australia
rogergraham@optusnet.com.au
http://members.optusnet.com.au/~rogergraham
iandol on mon 14 oct 02
Anyone wishing to start doing this style of craft process might care to =
have a look at:
Philip Romanoff, "The Complete Handbook of Centrifugal Casting...". =
1981.ISBN-8306-1153-3.
There is a phase diagram for Common Salt and Water. There are errors in =
this diagram. But the explanation of the Lead Tin diagram seems =
adequate.
The practical details are well covered but this is not the same process =
as that used by jewellers and dental technicians for high temperature =
alloys.
Best regards,
Ivor Lewis.
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