Electric Mid&Hi Fired Ceramics
Fire It Once
Glaze Application for Single Firing
For just about any question in ceramics there are two good basic answers.
- "It depends."
- "Try it!"
How to glaze ware for single firing is one of those questions that seem to lack cut and dried answers. Simon Leach glazes his pots by dipping and pouring in a short time frame on pots about leather hard.
Steven Hill pours interiors and sprays the exteriors and layers without a lot of concern for time between coats, but he starts with near bone dry pots.
The timing and techniques are going to be very dependent on the clay body, the glaze composition and viscosity, and the method of application to name a few variables.
A number of authorities insist that a single fire glaze have a high clay content to allow it to shrink like the clay body it is applied to.
Please use this forum to exchange info on how you glaze your work for single firing.
This forum is in response to a Kathy Ransom query
Comment by Kathy Ransom 4/13/2011
I just watched the Simon Leach video about using wax resists and didn't realize he does single firing. He dipped a bowl, then poured glaze into it and said that both inside and outside need to be done at the same time. Revelation!! I've been carefully brushing my glaze on and letting it dry before carefully brushing more on, thinking that this would keep the piece from absorbing too much moisture. I've had a few pieces just come apart though as they dried. Is his method a solution to this and has anyone else tried dipping and pouring in one go and had success doing it this way?
Anne Cunningham
Just joined so am replying "late" - I am interested in advice regarding application, too. I ordered some Ravenscrag slip - and made up a clear for porcelain, that worked well over Cone 6 "Frost" - a golden rather than ice tinge. but I am thinking it will be interesting to test on a few pieces of stoneware for single firing. Any advice? I am a dipper rather than a brusher.
By the way, Happy New Year, all!
Jan 1, 2012
George Lewter
It's kind of unpredictable. Especially with commercial clays where you don't know the makeup. If your glaze has 20-30% clay in it you can try dipping leather hard and see if it stays adhered. Glazes with less clay may need to be put on bone dry clay which may react by cracking or bloating, or be perfectly fine. I think its best to glaze bone dry ware quickly or let it dry for several hours between coats. I had good luck with Laguna #80 which is a medium brown stoneware. It seemed to tolerate dipping very well.
Jan 1, 2012
Anne Cunningham
Thanks, George, I will give it a try - my local supplier doesn't carry that particular Laguna clay but she will add a box to an order (I won't be buying lots) - I like a darker body in general. I noticed the shrinkage is about 14%, so I can use that as a guide. I am going to throw some bowls and cylinders in the bodies I do use (Highwater's's Speckled Brownstone, Earthen Red and Standard's Chocolate Brown #266). My interest is kind of a romantic one (harking back to the single firing days) as well as ecological and tactile - I like the feel of leather hard, dislike the feel of bisque, so more towards leather hard dipping, but some of my favorite glazes have a lower clay content than 20%. I guess I just have to jump off the diving board. I don't have a lot of time in my studio, and while I love to experiment, I would rather not have to reinvent the wheel, jealous as I am of my time and energy. I am intrigued by the idea of using dipping tongs and the actual marks they may leave o leather hard clay, as well as the challenge of designs that give one natural dipping finger holds. Of course bone dry dipping might not work with tongs ;-) - and if I can get my hands on some Laguna #80, would try the bone dry route. Heck, I'll try bone and leather on all of them. Thanks for your quick reply.
Jan 2, 2012