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Ray Bright

Glazing Greenware

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What you want to do is called 'once firing' .... You can click on the Ceramic arts daily link above and search the term for more info or Google it.

Basically it depends on your glaze and whether you want to glaze both inside and out. What happens if you do it wrong is your pot collapses right before your eyes.

WUVIE likes this

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I occasionally once fire/single fire. As Chris said you do have to be careful in application of the glazes, but since you said you want to spray the glazes, in my opinion, you are one step ahead for exterior glazing. In my instance, if I am glazing a relatively closed vessel like a vase, I pour the inside glaze in and out, wait a bit (not too hard if you are glazing several pieces), then spray the outside. For open vessels I spray the bottom first then finish with the inside top side. Some folks like to glaze at leatherhard, buit for me bone dry is when I choose. You have to watch the rims and bottoms and they are vulnerable, but it is managable if you keep your wits about you.

 

The other important part is the glaze formulation. Since the pot and the glaze are drying together, then being fire together, the glaze likes to have a good bit of clay in it. Formulating your own glazes tends to help when single firing, although I have successfully used commercial glazes with my homemade glazes.

 

As Jim (Offcenter) mentioned Steven Hill is well known for the technique. There is also an online group I am a member of you can join to benefit from discussions, recipe sharing, etc. There is no reason to go it alone. http://cone6pots.nin...roup/fireitonce and http://cone6pots.nin...in-the-cone-5-7

 

Pots were fired once for a very long time before the convenience of a bisque firing became common. Steven Hill says his reason for single firing is to reduce the lag between forming and glazing. He feels that he loses the spontaneity (sp?) with a bisque cycle in between.

 

I have attached some examples of my pots glazed with Steven Hill glazing techniques. With a little diligence you can find his glaze recipes, or you could buy the DVD for a lot of information.

 

 

John

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Dinah likes this

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Thanks everyone. I thought I was going to hear "don't do it" 10 to 1. But once-glazing seems common. My pieces are small, but very thick, 6" discs. I'll glaze the 'top' and spot glaze the bottom. A few tests, and I think I'm good.

 

Thanks again,

Ray

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Industry uses long tunnel car kilns and the heating up is real slow.

Single fire works fine if you have the time to glaze the green ware (a bit slower as one must be extra careful) and fire slow at first.

Mark

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Industry uses long tunnel car kilns and the heating up is real slow.

 

Here's a good example.

 

 

Actually there are some types of industrial priduction that are made and fired VERY fast.

 

 

 

And as you watch the above (love the music choice :lol: )........ you get a good idea of why OUR pricing structure should be WAY higher than commercial funstional wares. Go to a place (other than Walmart) that sells "fine china" anmd look at the pricing.

 

best,

 

................john

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Good advice from several sources regarding single firing.

 

One of the best books written on the subject aside from magazine articles is Single Firing -- the Pros and Cons, by Fran Tristram. You will not be saving any money with a single firing schedule because frankly you're tacking on a bisque to a gloss firing whether electric or gas or wood. Some may chip in with a quibble here, but the savings are quite marginal. The effects which you can achieve from single firing and spraying/dipping/brushing oxidation will be somewhat different from those you would achieve on bisque ware. Please do make an effort to look at Steven Hill's very accessible and generously shared once firing techniques at ^6 oxidation.

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According to the story I was told, single firing used to be the norm ... then, in large production facilities they introduced bisque firing to cut down on losses in the glaze application area. Is this true?

 

 

 

In the ceramics industry there was a 'sub' industry. It was the decorating aspects of the work. Many of the large manufacturers hired outside of the company for the decorating of their wares.

 

The greenware was shipped off to other companies or individuals for decorating (ladies at home mostly) and when completed it was shipped back to the factories for the final firing.

 

Much of the greenware was lost to bad roads, and being shipped in horse drawn wagons, and in poor packaging conditions in barrels of hay and saw dust.

 

By giving the ware a pre-firing or hardening called a ‘biscuit’ enabled the factories to have fewer losses in this particular aspect of the business. But creating better roadways and waterways in addition to the biscuit fire proved to incur fewer losses overall.

 

 

 

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