The queen was invested in a 16 inch diameter (40.6 cm) X 28 inch tall (71 cm) cylinder. I burned it out at 1000 F (538 C) for about 80 hours. It was not enough. I am going to burn her out this time for six days at 900 F.
The little crown piece was invested in a cylinder 12 inches diameter (30.5 cm) and 12 inches tall. I burned it out at 900 F. (482 C) for 48 hours. That was plenty.
There are a lot of conflicting opinions in the sculpture world about burnouts. It seems every book I read says something different. I have found that many, if not most, book writers tend to let other books do a lot of their research, the writers of which let yet other books do their research. It's kind of circular. So I finally found a man who knows what he is talking about. B.P. Fink is a professional. He has poured hundreds of both ceramic shell and plaster investment molds. He much prefers plaster investment. You can find his wisdom on the http://www.artmetal.com/
forum. He burns out at 900 F. for six or seven days. That's a great forum. Not much chit chat, but some real knowledgeable people who are right there when I need them.