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alumina question

updated mon 13 feb 06

 

Weiland, Jeff on fri 10 feb 06


Glaze question: I am mixing a bunch of test batches of ravenscrag glazes
and ordered alumina. The recipes call for calcined alumina and received
alumina hydrate. What is the difference and can I easily convert the
percentages without a lot of hassle or do I need to reorder the calcined
alumina?

Jeff Weiland
Greenfield-Central High School
810 North Broadway
Greenfield, Indiana 46140
317-462-9211
jweiland@gcsc.k12.in.us

Hank Murrow on fri 10 feb 06


On Feb 10, 2006, at 1:06 PM, Weiland, Jeff wrote:

> Glaze question: I am mixing a bunch of test batches of ravenscrag
> glazes
> and ordered alumina. The recipes call for calcined alumina and received
> alumina hydrate. What is the difference and can I easily convert the
> percentages without a lot of hassle or do I need to reorder the
> calcined
> alumina?

Why not just calcine the alumina hydrate in a bisque bowl in your
normal bisque firing?

Cheers, Hank
www.murrow.biz/hank

Ron Roy on sun 12 feb 06


Hi Jeff,

You will need about 1.5 times the amount of alumina hydrate to take the
place of the calcined alumina.

The suggestion to calcine some of the hydrate should prove this out - I'm
not sure what temperature you need to take the hydrate to but I assume
bisque temp will be more than enough.

RR



>Glaze question: I am mixing a bunch of test batches of ravenscrag glazes
>and ordered alumina. The recipes call for calcined alumina and received
>alumina hydrate. What is the difference and can I easily convert the
>percentages without a lot of hassle or do I need to reorder the calcined
>alumina?
>
>Jeff Weiland

Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513