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Re: Re: Casting Blanks

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Posted by Stephen Campbell on January 29, 2001 08:43:26 UTC

Thanks for the link,look up sundance art glass center on the web,they have a fusing/annealing kiln for a little under $500 with a 14" x 9" firing chamber,it gets up to 2200F with side elements running on 120vac,has optional top elements/pyrometer/and other accessories,this might be a good starting point,just to have something to experiment with, im thinking about buying one,a problem with this for annealing could be that the temp controller shuts off automatically when it reaches a certain temperature, i have to call this company and find out if this is the case.
Master optician Bob Goff recently told me to use armstrong A25 or better firebrick,and Kanthal silica nitride heating elements,he also mentioned that avoiding straia is very important,i have an old corning blank which has alot of straia,probably was made back in the 40's or 50's.
The annealing process will be the most difficult part, the heat has to be reduced by a fraction of a degree per minute over several hours
so this pretty much rules out manual control.
Would you know of a source of firebrick at a reasonable price? i found a company with 2600F rated for $4 a brick(9"x4.5"x2").

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