Vince Pitelka on thu 27 jun 96
Ginger -
I have had only mixed luck applying terra sig to bisqueware. It can only be
applied as a very thin layer or it will flake of. If it is a very pure,
thoroughly refined terra sig, you can still get good coverage and shine with a
very thin layer. This is the only kind of application to bisqueware which has
worked for me. Such an application would not be appropriate for a painted
design. If your design flaked off it is most likely because the terra sig was
applied too thick to the bisqueware.
Regarding the temperature of bisque and the clay's receptiveness to smoke
effects, that is a harder call. Were these wares also coated with terra sig
after the bisque? A proper terra sig finish is very dense, and you can expect
more subtle smoke effects than with a plain porous clay surface. How fast did
the sawdust burn away? As has been discussed recently on Clayart, sawdust
smoking is not a true firing process, and relies on a slow smoldering fire to
impregnate the wares with smoke effects. If it burns too fast and too hot you
won't get much in the way of smoke effects. Many sawdust firers dampen the
sawdust slightly, often in layers, in order to encourage more smoke and
varigated effects. What was the texture/grade of your sawdust? If it is too
fine it burns too slow and sometimes goes out. If it is too coarse (as in
planer shavings) it will burn too fast.
So, you need to do some more experiments to determine the best sawdust
firing equation to achieve the effects you desire.
- Vince
Vince Pitelka - wkp0067@tntech.edu
Appalachian Center for Crafts, Smithville, TN
Claudia O Driscoll on mon 1 jul 96
re:sawdust fires
I have worked with potters who add up to 50% peat moss to their
sawdust for darker tones.
I have had good luck with very fine sawdust, but make sure to have a
good fire going before I cover it. In more than 10 years, only one has
gone out....and that was when my mother asked, "Has one ever quit on
you?" "No"..I said. Gotcha!
claudia (claudiao@clackamas.cc.or.us)
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