I once heard an elderly potter say “if I don’t like what I’m getting, I just fire it again.” That was not easy before potters began to fire pottery in electric kilns. In fact, those extra firings often resulted in pots for the yard, if not the garbage can.
Firing pottery at Cone 6 in an electric kiln (in oxidation) wasn’t exciting in the past either. Potters often frowned upon the results, and those with gas or wood-fired kilns which make use of oxygen reduction to bring out the beauty of their glazes swore they would never switch to oxidation. You just could not get a lot of great color development unless you were using commercial glazes–or so it was believed. How could you get that great variation in glazes on your pots if you didn’t have the magic of the reduction fired atmosphere which helped add variety and depth and interest on just a single pot?
But potters love to invent, whether it’s a new tool for their use in the studio, or a new glaze to put on their beloved pots. It seems much of the fun comes from experimenting. While there are still lots of potters quickly dipping their ware in buckets of glaze (and it’s admittedly much less expensive with so little waste), many of us are also using spray booths. This requires a good safe space to work with phenomenal ventilation. It also results in lots of waste of glaze chemicals. The upside, however, is that it enables a very even coating of glaze without the dreaded unintended drips marring the final surface finish.
Not that drips aren’t sometimes desired. But for a potter to be truly happy or excited, those drips need to be placed in such a way as to enhance the work. And since we’re firing in oxidation, and we’re spraying the glazes, well then why not look for ways to enhance color and texture by spraying different glazes onto a pot.
Yes, there’s a lot of experimenting, and not just a few disappointments to contend with along the way. Each glaze causes reactions within the heat of that kiln, and some of those reactions aren’t just to the heat, but to the different glazes introduced.
But back to the original statement, about firing again; it is now not just to salvage failure, we re-fire with intent. We increase the number of firings in order to bring about results we could not otherwise have with the typical bisque followed by one glaze fire. We don’t just add the exciting variety that potters formerly achieved with gas or wood-fired kilns: we have taken that to brand new heights. We don’t have to spray a pot evenly with just one color, we can use bits here and there, spraying gently, choosing a heavier application here and lighter one there.
After our initial bisque firing, we fire glazed pots at lower temperatures to ensure that the glazes adhere or you might say that they are baked on, usually at cone 04 somewhere in the neighborhood of 1900 ° F. Sometimes we add more glazes and again fire at that low temperature before finally firing our pots to maturity (or to a stoneware state) at Cone 6, approximately 2200 ° F. Some pots may have 3, 4, or even 5 firings before we decide they’re finished and ready to sell.
For a final finish, some of our pots are treated to a crawl glaze application, and this, too, is comical when we think about the former “taboo” of having a glaze crawl on our pottery.
With electric oxidation firing, we can play to our heart’s content. We can introduce and generally control the crawl so that it enhances our work. And that’s true for our ash glaze applications as well. Ash glazes tend to run, but instead of worrying about the runs, we carefully introduce them just where we know they are likely to bring about some incredible beauty. The pots that in ages past relied on wood ash to create their glazes, well, I guess we’ve experimented and found ways of using them in an electric oxidation atmosphere.
And just like that elderly potter, we’re happy to believe that we can even re-fire a pot that had previously reached stoneware maturity.