Finishing your Pottery: Glaze Fire

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Firing Your Pottery: Step 2

Once glaze has been applied to a pot and allowed to dry it needs to be fired again to get the glassy surface most people think of when talking about pottery, so back to the kiln! The pottery is placed on shelves again, just like with the bisque firing, but with glaze firing you can’t stack pots one on top of another because they’d fuse into one when the glaze melts so no touching! Not pot to pot, pot to shelf, or anything else.

When I fire my medium-sized kiln to it takes about 8 hours to reach maximum temperature (2192°F; ~1200°C) and I let it cool down overnight. The pots are still warm to the touch when I open the kiln the next morning.  But don’t sneak a peek! Opening the kiln while it’s firing or cooling can let in a draft of cold air which can lead to cracking, which would be a shame given all the hours you’ve already put into making that pot.

Glazed pottery before firing.

And the same pieces of pottery after firing. For the giraffe plate, I hand painted the giraffe with black underglaze prior to adding the translucent brown glaze on top.

As you can see the color of the applied glazes frequently don't resemble the final fired glazes. This is why potters like to use test tiles, to give us a better idea of what the glaze looks like once fired.

So now you know, pottery making is a laborious process that involves several steps and many, many hours (even if it’s just waiting for a pot to dry or be fired). People often ask artists why a piece of pottery costs so much, it’s not so much the cost of the clay or glazes, or the electricity/gas to fire the kiln, or even the capital investment of the kiln, it’s really the experience that potter has gained over the years of practice and the time it takes to create each piece of pottery by hand. 

And you ask what about the ceramic dinnerware set I can buy for $25 at the local big-box store? The difference comes down to volume, when ceramic pieces can be made by the hundreds using a mold, glazed in en masse, and fired in gigantic kilns, we’re talking a whole different ballgame. Artisans you see at craft fairs, on Etsy, and in galleries have hand crafted individual pieces of art for your enjoyment.

I hope you’ve enjoyed this overview of pottery making. If you want to learn more there are hundreds or books and probably even more websites dedicated to the art of pottery making. And if this has whetted your interest and you want to give pottery a try, check your local art centers, schools or community colleges, they typically offer pottery classes for all ages and skill levels.

Next time I will tell you about raku, a unique firing process that produces beautiful metallic glazes.

Firing Your Pottery: Step 1, Bisque Fire

To get to the point where you have a shiny, maybe colored, piece of pottery in your hands takes two firings in the kiln. Bisque firing is the first firing. 

Once you’ve make your ceramic piece by whichever technique you prefer (hand built, thrown, etc.) and its dried sufficiently, it can be bisque fired, which leads to a hardening of the clay. How dry is dry enough? Good question. That depends on the environment since weather can effect drying times hugely. If it’s humid, pots will take longer to dry. But be careful, if that pot is not completely dry it can explode in the kiln. I've been there and done that and it's quite a mess to clean up and not good for the kiln’s heating elements.

This is my medium-sized kiln

This is what the pottery looks like when stacked in the kiln. 

This will be the bisque firing (pottery can be stacked during the first firing). This side view stack of pottery is actually sitting on top of my big kiln (I’m 5’5” and the big kiln comes up to my waist!).

Here's a top view as I'm loading the kiln.

Once the firing is done you have to wait several hours for the pieces to cool down so you don't burn your hands touching them.

Next post it’s time to glaze!