Tom's E-mail on mon 29 apr 02
Thanks to everyone who responded to my question about the bone ash. =
Perhaps I was unclear but I have in my possession both the bi-calcium =
and tri-calcium forms. In the digital fire reference book, Tony Hansen =
lists bone ash as the tri-calcium form [CALCIUM PHOSPHATE - Ca 3 (PO 4 =
)2] and in Insight lists the fired breakdown product [I assume the =
tri-calcium] as 1.000 P2O5 and 2.993 for CaO. Since my fake pine ash =
formula calls for a relative large amount of CaO and small amount of =
P2O5, I believe I will be okay if I use bone ash to supply the needed =
P2O5 and make up the CaO difference with whiting. I still haven't found =
anything meaningful for the breakdown product of the bi-calcium form. =
Other reading since I first posted indicates that the tri-calcium form =
is preferred in glazes - no reason given, however. Is there a use for =
the bi-calcium form? And if so what is it?
Thanks again
Tom Sawyer
tsawyer@cfl.rr.com
| |
|
