DLB Posted November 27, 2019 Report Share Posted November 27, 2019 I recently ran a cone 04 bisque firing. After glazing the pieces and firing, many of the pieces were ruined with pinholes. Ruling out the myriad of reasons for this, I called Skutt to talk to someone about the firing. It was recommended that I bisque on slow and hold for 5 minutes. He was guessing that all of the carbonates etc did not burn out of the pieces during the bisque firing. Here’s the question. I still have some unglazed pieces from the under fired bisque. Can I run them thru another bisque? Link to comment Share on other sites More sharing options...
liambesaw Posted November 27, 2019 Report Share Posted November 27, 2019 Yes, you certainly can! Link to comment Share on other sites More sharing options...
Bill Kielb Posted November 27, 2019 Report Share Posted November 27, 2019 Yes you can. A typical bisque schedule is 10-12 hours and generally does not exceed 200 degrees per hour. If you have an automatic controller then slow bisque would be the one to try. This May work and you may have to reconfirm it with some actual greenware at some point just to be sure. There are many reasons for pinholes. Link to comment Share on other sites More sharing options...
Hulk Posted November 27, 2019 Report Share Posted November 27, 2019 Hi DLB! The thread below has links to firing schedules (thanks again to glazenerd) - my recollection is there are three (four if you count drying out the pieces, water) critical temperature ranges for bisque; I have them written out in my notebook. Once dry (water) I go full blast when between the critical ranges, and slow down considerable within the critical temps, particularly for red and brown clays. https://community.ceramicartsdaily.org/topic/20132-slow-bisque-kiln-help/ There's some good reading in there about why, what, and how... The other practice that seems to help (for microbubbles in my cases) is to hold for about an hour at 100F below peak temp the glaze firing: hit peak/target, allow to drop about 100F, then twiddle the switches to hold there for about an hour, then all off. Link to comment Share on other sites More sharing options...
Seth A Posted November 28, 2019 Report Share Posted November 28, 2019 For sure. I have a new kiln and am new to firing in general, so as I've learned more about its characteristics I have gone back and re-bisqued some pieces from questionable firings. FWIW on my bartlett controller I now do a slow bisque to 04 with a 20 minute hold and a pre-heat if I'm feeling nervous. My kiln is small, 18" x 18", and without the hold fires fairly unevenly. Link to comment Share on other sites More sharing options...
DLB Posted December 4, 2019 Author Report Share Posted December 4, 2019 Thank you all! I did re fire the bisque load and feel confident about the glaze fire now. Link to comment Share on other sites More sharing options...
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