Bisque at Cone 10 and then Glaze at Cone 6

[Shine Chisholm]

Is firing at a higher temperature for bisque than for glaze really that unheard of?

It's the way I was taught and have been firing. I've been working out of my home studio for the past three years, and the ceramists and potters in this area are often downright rude about how I am "doing it wrong."

I like the work I make and people buy and use it. In that sense, I'm not doing it wrong.

It seems like there should be at least some school of thought that coincides with what I was taught. Where is it hiding?

NOTE: Replies are posted from oldest to newest, so the most recent posts will be at the bottom of the last page.

[Shine Chisholm]

My stuff stands the test of oven, microwave, freezer, and-- for the stoneware-- dishwasher.

[Shine Chisholm]

I will be honest, in going back through my pictures, I'm very aware of my less-than-stellar feet. regardless, here are some dipped or poured pieces:

I also do a lot of mixed pouring and brush-work. I especially like filling the vessel and pouring out the glaze with an intricate glazed design on the outside.

[Donna Ferrara]

then it's all good ; )

[Shine Chisholm]

Thanks, Donna. I like my process. I was feeling a bit lonely, though. The more I interact with other ceramists, the more I am told that I'm wrong. It's wearying.

[Patricia Bridges]

Thanks, If I didn't know anything about your firing, (based strictly on a technical perspective) I would say there is a problem with your clay and glaze fit and firing temps. On many pieces there are weird textures that are tell tale of that as well as a lot of crawling (glaze not sticking to clay body). If it were non-functional ware I would not be bothered but for functional ware I find it distracting. Just my opinion.

[Shine Chisholm]

Good to know. I guess since this is the way I've always done it, it's what I've come to expect.

I will have to try reversing my process to see if I like it.

[Donna Ferrara]

i'm not sure it's a wrong or right issue, just make sure the fit is good

because you are making functional ware

it's a complicated issue, because there are a lot of things to consider

most people start with glazes that are engineered to fit their clay body, theoretically so there will be less problems.  but as we all know, once you add in the application of glazes, or the firing and firing cycles into the mix you can have lots of issues.  familiarize yourself with what crazing, blistering etc looks like, and examine your ware....

you might have to add additives to your glazes to make them adhere better while glazing

Often after extended use, fit issues can come out....but if you're not experiencing this, then you should be ok

I don't see any difference in what you are doing from the cone 6 potter who accidentally overfires a bisque, and then glazes with cone 6 glazes. or someone who refires their work.  it seems to be the same thing. ; )

[Shine Chisholm]

I have no plans to stop firing my porcelain to cone 10. I am just now reaching a point where it would be beneficial to separate stoneware and porcelain firings, and then I can vary my temperatures more widely.

One of the reasons that this whole issue is so surprising to me is that I am reasonably educated in the area. I am familiar with crazing and blistering-- although apparently not to the degree that I thought I was. I studied studio art, with a focus on ceramics, at the University of Iowa. When I first moved to Detroit, I figured that people in this area just used a different method. After three years doing this professionally, however, I would have expected to find more people who are at least familiar with the process I was taught.

Thanks for the feedback Donna and everyone else. I do appreciate it.

[Victoria Cochran]

Firing higher for bisque, than for glaze, is more common with earthenware glazes and not typical in high fire, because of the vitrification issues already mentioned. Many who've worked in earthenware are surprised to find it's done "the opposite way" with midrange and high fire clay bodies.

However, while it's unconventional that you do this for a single color application on a high fire body, in principle, your process (firing high to low) is not "wrong" -- in fact, it's been essential to some pretty snazzy historical pieces and modern ceramics.

Highly decorative work, involving multiple firings, starts with the highest firing, and then progressively adds glazes, overglazes, enamels, china paints and/or lustres in firings that are each incrementally lower, to accommodate the lower temperature of maturity required at each step. An appropriate clay body, and glazes, will tolerate the multiple submaturity firings to successively lower cones.

So yes, if you want to keep the brilliance of those lower maturing glazes, your method is spot on & some pretty smart people have gotten a lot of mileage out of the method.

http://overglaze.demaine.org/?page_id=201

http://allhandmade.net/2010/11/22/lubna-chowdhary-ceramic-artist/

[Shine Chisholm]

Thank you. Thank you very much.

[Victoria Cochran]

The allhandmade link seems to have expired. The information is now here: http://craftedbydesign.wordpress.com/2010/11/22/lubna-chowdhary-cer...

[Kathy Ransom]

I was given some low fire glazes so I've tried firing to cone 6, often with a cone 6 liner glaze on the inside of mugs, etc, applied the glaze and refired to cone 06.  This works really well but the odd cone 6 glaze has come out pitted and changed by the refire, so now I try refiring the glaze on a test tile just to make sure I like the change if there is one.