Bisque fired to cone 04, can it be fired to cone 6 for glaze?

[Just J]

Hi, I'm trying to reglaze pieces that I've done that didn't exactly turn out the greatest. They've all be bisqued to cone 04 and have gone through one fired to cone 06. I was wondering, if I were to glaze it again with a cone 6 glaze, would it melt after already being fired? It's a low-fire whiteware clay. 

[Bill Kielb]

If it’s lowfire clay you likely could try  lowfire glaze and fire to 04. Cone 6 is too hot for your clay anyway so that would likely turn out poorly. In general clay and glaze should mature at the same cone and refires generally don’t succeed.  Downfiring, that is to say using a lowfire glaze on a midfired piece can be more successful than just refiring midfire stuff. Some folks layer their decorations this way.

[neilestrick]

Low fire white clay will begin to melt around cone 1 or 2, a puddle by cone 6. You can only fire to the temp that your clay will mature. You can add more low fire glaze to your pieces and fire them again at the same temp and see what happens. You can also try going a little hotter, like cone 05 or 04. A little more glaze melt can make the surface more interesting.