The ceramic bisque firing is the first firing in the ceramic process. It’s the transformation from clay into ceramics. It’s the essential intermediate step. Between hand-shaped clay and glazed work. After this firing, there is no turning back to the clay bin.

I hear people lyrically talking about their last raku firing. Tears of joy when digging for a pot from a pit fire. Trembling hands of anticipation when opening the kiln door after a glaze firing. But never exciting stories about the first firing. No cheers when the lid of a bisque kiln is lifted.

The bisque firing is the step child of ceramics. But the firing process is magical– even a bisque.

Why skip the ceramic bisque firing?

In short, no one gets excited about a bisque firing. At most, an expletive under one’s breath when an S crack is detected in the bottom of a bowl. And sometimes not even under one’s breath…. Some potters just skip this firing completely.

“Single fire glazing” or “raw glazing” this is called. And there are good reasons for doing so. It saves:

• Time: throwing, drying and glazing, all in one go.
• Energy: fire just once; directly at glaze temperature. Not twice. Not first at a low temperature, waiting for the ware to cool, glazing and then fire it again to a high (er) glaze temperature.
• Money: Less time and less energy = less cost.

In short, it saves. In ceramics industry, the single fire glazing is certainly popular.

Why do a ceramic bisque firing?

You might wonder why I still bisque fire my work. Why this waste of my time and effort before I glaze my work and finally fire it again at much higher temperature.

I do it because there are benefits. Bisque-fired work is:

• Stronger. Bisque-fired ware is much less fragile than when it is leather hard or even bone dry.
• Porous. Bisque-fired work sucks the water from the glaze much better then unfired clay (greenware). It is therefore easier to apply.
• Stress test. Uncover errors before glazing.

For me, the main reason is the “stress test”. If my work can get through a low firing at about a 1000 ⁰C (1830 F), then it can also survive a glaze firing at about 1280 ⁰C (2330 F or cone 10 in pottery speak).

Only when it’s very very dry

If something goes wrong during the bisque firing, it would certainly happen in the glaze firing. And anything can and will go wrong when ceramics are fired. Such as:

• Explosions
• Breakage
• S cracks in the bottom
• Etc, etc

That’s why, as with banks, it is important to always carry out a stress test. And only fire when you are sure your work is dry. And I mean as dry as a martini, so very, very dry, before switching on the kiln.

A little moisture in clay can lead to a disaster in the kiln. Just as sure as money-drunk CEO’s will lead to a banking crisis.

A kiln full of promises

So as far as I’m concerned, the first firing is an (almost) indispensable step in the firing process. A control step and an operation that makes glazing easier.

But it’s more than that. It is the chemical conversion of soft clay into a stone-hard material. From shapeless clay to design. It’s an exciting test of your clay skills.

In short, a kiln full of promises. The promises of beautiful handmade glazed ceramics … or not..

Okay, I’m going to stop writing now, the kiln has cooled down. I’m about to unload. No hurry. After all, it’s just the bisque firing 🙂

BOL stoneware cup

Robust stoneware cup, hand-thrown on the wheel, for daily enjoyment!

€35,00

Shop now

About Post Author

Daniel Bende

Designs and creates under the trade name DFB-ceramics hand-thrown stoneware figurative ceramics.

See author's posts