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fwd: saggar firing question

updated thu 18 oct 01


mel jacobson on wed 17 oct 01

>Hi Mel,
>I hate to do this to you, but I still can't figure out how to post (I
>read posts through yahoo groups and when I try to pot the "To" screen
>remains blank and regardless of what I type in there, it seems to get
>sent back to me.) So I was wondering if you could post this for me so
>I could see what people have to say.
>Here it is:
>Hi, I have a question about saggar firings. I've been saggar firing
>for a while now but have recently decided to lower the firing
>temperature I usually use in order to best preserve my burnish on the
>earthenware pots I make. I fire in a small gas kiln with a built in
>brick and silicon carbide saggar box. I usually only use copper
>oxides in my firing with rock salt. I fire to an external temperature
>of cone 06, the internal temperature of the saggar varies from cone
>08 to a low of cone 012.
>Anyway, I decided to start firing lower, to probably an external
>temperature of cone 010 or even 012, but have noticed that the rock
>salt isn't burning away completely even at cone 06. Then I fliped
>through Hamer's book and saw that Sodium Bicarbonate has a melting
>point way lower than NaCl by almost 1000 degrees F. Was wondering if
>it would be horribly detrimental to the kiln or my pieces if I
>started to use sodium bicarbonate in my saggar instead of regular
>household salts. Will it even make a difference? will it turn into a
>glaze inside the saggar?
>_jeff Tsai

Minnetonka, Minnesota, U.S.A.
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