Refiring

[Mossyrock]

I have a quick question. I checked the archives, but couldn't find a 'standard' answer, if there is such a thing. If you've glaze-fired a kiln load and it reached the correct temperature, but the glaze on a couple of pieces needed to be reapplied in places and the pieces refired, do you fire to the same cone, a cone higher or a cone lower? Would the answer apply to both low-fire and mid-range fired pieces? If the pieces are 'passable', but not what they should be, would you refire? Isn't there a risk of cracking in a refire? Thank you for your help.

[neilestrick]

Pots can be refired. We often refire pieces here if there is a small glaze flaw that can be touched up. Most clay bodies don't mind, but some will crack. Some forms like to crack more than others, too, like platters and big pieces. Go ahead and refire at the same temperature, unless the problem was temperature related. If the flaw is only noticeable by me, I don't bother refiring.

[perkolator]

ceramics can technically be fired over and over - think of the kiln furniture - but the reaction depends on the clay body. it is also not uncommon for multiple-fired work to have their glaze's melting point lowered after a repeated firings - as in a glaze that runs at ^6 may start running earlier at ^5, etc. for a one-time re-fire, I wouldn't worry about this and you're most likely good to go with the original firing temp - but if you're planning to work this way just keep that in mind.

 

getting glaze to easily stick to an already glaze-fired object is a different story.....some tricks are: warm up the piece first, use heat/fan to evap water faster, thicker glaze, add CMC, add corn syrup, etc.