Snail Scott on sat 9 dec 00
At 01:38 PM 12/9/00 -0600, you wrote:
>Fact: Plaster mixed with water and then added to clay does not work.( It
>will lime pop)
>Fact: Plaster dry mixed as a fine powder (sieved) with a dry powdered clay
>"body" (10-20-30% plaster per 100% clay) does work.
>Fact: Bronze casters have used this for investment casting for years! Metal
>casters actually increase the percentage of plaster and decrease the
>percentage of clay!
I also work in bronze as well as clay. This clay/plaster mix is mentioned
(I think) by Cellini, who wrote in the 16th century. Remember, the originals
for most bronze sculpture in this era were made of clay, and plaster gesso
was widely used by artists for all sorts of stuff. These materials were both
readily to hand. I don't know why it works, or how long it lasts, but for
molds, it's got a time-honored track record.
Cellini also has (I believe) the first mention of paperclay, which he
describes as his secret personal invention. Actually, he took old rags
and rotted them down to fragments (cotton linters, anyone? Rag paper?)
when mixed with clay. He describes the result as having many useful
properties, including strength, flexibility, plasticity, and resistance
to cracking, far superior to regular clay. Sound familiar?
-Snail
Roger Korn on sun 10 dec 00
These folks are talking about making investment from 50/50
Plaster/silica to create a mold that will work for glass casting
temperatures: http://www.warmglass.com/ . LOTS of good info here.
Roger Korn
McKay Creek Ceramics
| |
|
