Keiko Suga & Noel Oard Mapstead on thu 21 sep 00
hi martin
would you consider your pet bone ash analysis to be similar to human bone ash?
would there still be a higher CaO to P205 percentage?
besides the pet bone ash being an opacifier, have use experienced getting a blue
opal effect? either at raku temp or stoneware temp?
i have gotten some beautiful opal effects, but never everytime, hit and miss
i teach a workshop in feb 2001, using human bone ash for glazing. currently doing
alot of research and experiments
thanks, noel oard mapstead
Hank Murrow on thu 21 sep 00
Noel Mapstead wrote;
>besides the pet bone ash being an opacifier, have use experienced getting
>a blue
>opal effect? either at raku temp or stoneware temp?
>i have gotten some beautiful opal effects, but never everytime, hit and miss
>i teach a workshop in feb 2001, using human bone ash for glazing.
>currently doing
>alot of research and experiments
Dear Noel;
I would argue the point about bone ash being an opacifier. Perhaps at
lower-than-stoneware temperatures this is true; and I have little recent
experience in that realm. At, and above C/10 however, I feel confident in
claiming that the phosphorus content in bone ash is acting as a
network(glass)former. In fact, I have done several Currie Tiles to
demonstrate this behavior; and am currently using a glaze which contains
50% bone ash, and is lovely as a ware glaze, being both durable and
beautiful, yielding rich tomato colors from Fe and Ru. Opalescence appears
at C/12 with this glaze. I recommend you try some Currie assessment tiles
to find out what your ash will do_____Let's compare notes, Hank in Eugene
Martin Howard on fri 22 sep 00
would you consider your pet bone ash analysis to be similar to human bone
ash?
Yes, I don't see why not.
would there still be a higher CaO to P205 percentage?
Can't see why there should be, but surely someone somewhere has tested human
ashes. If not, it could be done.
besides the pet bone ash being an opacifier, have use experienced getting a
blue
opal effect? either at raku temp or stoneware temp?
Not got into raku or opal effects, yet.
I have gotten some beautiful opal effects, but never everytime, hit and miss
I teach a workshop in Feb. 2001, using human bone ash for glazing. currently
doing alot of research and experiments
We all look forward to reading your results, noel.
It is an interesting line of research, but we must give a thought to the
problems of passing on BSE particles and the sulphuric acid problem.
Martin Howard
Webb's Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
England
martin@webbscottage.co.uk
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