Bisque firing at cone 05?

Ceramics
1

Hi Kiln Team,

I have a couple pieces thrown using clay that I was told should be bisque fired at cone 05 instead of cone 04, would that be ok? Or would it have to be part of a special firing?

Thanks,
Ken

2

I have 2 questions. What is the clay? And who told you that Cone 05 was necessary or desirable? Typically clay isn’t so finicky for the bisque fire. We tend to fire to Cone 04 to solve some other clay finickiness, mostly outgassing for the darker clay bodies.

3

I see, I’m not sure what kind of clay it is because I got it from a shop in Mexico, and a worker there wrote “bisque 05” and “glaze 6.” I’ll leave a note on the pieces. Thanks!

4

Ah. So bisque at 05 is more of a recommendation, not something absolutely required. It will probably be fine fired at 04. The bisque fire is rarely important to the overall effect on the piece. We are usually concerned more with the glaze fire recommendations, rather than the bisque recommendations.

5

Oh great, thanks!

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6

I would highly suggest that you test fire a small piece of this clay through bisque and glaze to make sure you know how it does in our firings. If by any chance it was mis labeled this could be an issue for your piece and/or the kiln. Both could be damaged.

Test firing should happen in a lipped tray so that if there is an issue it can be contained to the tray.

Thanks!

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