Working With Porcelain: Why It Isn’t Difficult—Just Different
Porcelain is often regarded as a challenging clay body to work with.  Potters who attempted it often like the medium, however some give up not understanding how to handle the medium. They perceive it as fragile, finicky, and tedious. However, my challenging personality and years of experience have led me to a different perspective. Today, I advocate for working with porcelain clay. While it is demanding,  the rewards and benefits make it all worthwhile. ​
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My Early Journey With Porcelain Clay
My first experiences working with porcelain, was unsuccessful. To make it worse, more experienced potters and instructors  intimidated me. In my early days of pottery I created simple forms, fired to cone 8.  
Much of my early porcelain work ended up in pit firings. I created incredibly thin porcelain pieces that were fired in pits. These works eventually helped me secure permanent residency for my family and me in the United States.  
Those early works evolved into sculptural pit-fired pieces that carried my emotions during a time that I was still griefing the loss of leaving my home country,  South Africa.
​Eventually, the heaviness lifted. I began seeing light, movement, and ballerinas in sheer dresses in my mind’s eye. Southern Ice porcelain became my medium of joy. Translucency, color, and light became symbols of the future.

​Porcelain isn’t difficult. It’s different.
Unlike stoneware or earthenware, porcelain is worked as clay but becomes something closer to glass when fired.
Understanding that single truth changes everything about how you handle, design, and fire it.

Why Porcelain Cracks: Understanding the Real Causes 
Cracking in porcelain isn’t random—it’s usually caused by handling, design, firing, or glazing mistakes, to name a few.  Over the years, I’ve seen every kind of crack imaginable, both in my own studio and in work sent to me by students from around the world through TeachinArt.com.
Let’s break them down.

​Why Porcelain Handles Crack (And How to Fix It)
Many potters struggle with porcelain handles. The real culprit in most cases is particle orientation.
Clay shrinks in unison only when its particles are aligned and compacted evenly. A handle, unconditionally of the way it is formed,  has its own direction of particles, and when you attach it to a mug, it’s like two traffic flows meeting head-on.
You need an off-ramp.
How to Attach Porcelain Handles Successfully

• Score and wet thoroughly. (remember slip particles are diluted and in disarray!)
• Attach when both parts are equally moist
• Compress and blend the joint well
• Think about handles as foreign objects that must become unified with the form

If cracks still appear, look at possible mistakes in your design and firing schedule, not just the joint.

Preventing Design Cracks in Porcelain Work 
Porcelain must be formed evenly. Uneven thickness leads to slumping, tearing, and cracking.
At high temperatures, porcelain becomes  pyro plastic — it softens like glass. 

Design Tips for Porcelain

• Keep walls consistent in thickness
• Avoid heavy areas attached to thin ones. 
• Heavy clay will be drawn towards the kiln shelf and will drag thinner clay along with it. 

Firing Cracks and Dunting in Porcelain
Dunting happens when the kiln heats or cools too fast. It can occur in bisque or glaze firing.
If a piece comes out of the kiln split cleanly in two, or cracks days later with sharp, glassy edges—the cooling cycle is usually to blame.  
Dunts in bisque ware is not   common in porcelain clay, but glaze cracking happens often.  
How to Prevent Firing Cracks

• Slow down your firing and especially the cooling schedule
• Pay special attention to cooling around quartz inversion
• Don’t rush porcelain through temperature changes

Antoinette Badenhorst, a renowned potter, presents online classes and hands-on workshops worldwide. In 2014, she and her husband, Koos, founded TeachingArt Online School of Art. Together with other experienced and renown teachers, they provide comprehensive online courses for potters and artists globally. These comprehensive learning experiences are meticulously designed to enhance skills, boost confidence, and foster a deeper understanding of pottery, rather than offering mere demonstrations. 

If you enjoyed and gained something from this blog post, please share it with your friends. Unfortunately, I won’t be traveling abroad this year because I need to catch up on my studio work and am also writing a book. 
Details of my next ​porcelain workshop is available  on the Workshop page

It was very visible in the light colored porcelain mug. (Image above) Many mugs will not show this kind of defect and as you all know, it is the perfect place for dirt and bacteria to gather. Any well vitrified clay object can be subject to too thick layers of glaze and it can be disastrous in any clay body if the problem is not addressed. 
I took the mug outside and knocked it on the cement to break it.( Yes I protected my eyes with safety glasses) and I have to tell you, it took me about 5 really hard knocks, before it broke. Did I mention that porcelain is a really strong ceramic medium?
Anyway, the way it broke shows clearly a too thick layer of liner glaze inside the mug (see image below).

Even walls and an even application of glaze on any functional clay object is crucial. In this case the glaze layer was too strong for the clay body. Since it is a clear glaze, it is possible that I double glazed it without realizing the mistake.
Prevent thermal shocking during the firing process. A kiln that is fired too fast or that fires unevenly may cause trouble, not only with dunting, but possibly with warping too.
Obtain knowledge of silica and its behavior in pottery clay and glazes and especially how it will behave during firing of a pottery kiln. ( Silica, often a culprit in the studio,  is an interesting topic for potters to review.) See: Kilns suitable for porcelain in the near future.
Potters must make sure their glaze and clay body is a good fit for each other. There are glazes that are simply too strong for the clay body in use and instead of just shivering, it may tear and crumble a pot up into pieces.
Glazing on just one side of a piece, may cause dunting, when the stress of expansion and shrinkage on one side is stronger than the other side.
Large plates, platters and trays often tends to dunt when it is not properly set up in the kiln Learn how to fire plates.

When a crack is long and ongoing with a sharp edge, it is most certainly a dunt. This type of cracking can appear in the clay or the glaze or in both. They may appear vertical, horizontal, spiral or with a ragged edge all over the object. 
If the crack is soft and rounded, it means that glaze moved and melted into the crack. The obvious observation is that the crack was there before the glaze melted. This type of crack is unrelated to dunting.

It is important that pottery users realize that they are working with a glass-like product that can break and chip if it is abused in the kitchen.

Here are a few tips to be aware of when you buy pottery.
Always inspect your pottery directly after you received it from any ceramic artist; especially when it is shipped to you. 
Make sure it does not have hidden cracks, by tapping with a wooden spoon on the rim. A cracked piece will have a dull sound.
If you are about to subject your pottery to heat or cold, ALWAYS avoid sudden temperature changes. NEVER take a bowl or casserole dish straight from the refrigerator to the oven or vise versa. Not only is it a dangerous practice in which you can get hurt, but you will most certainly loose your precious bowl.
If you observe a crack, understand when it is a dunt and when it is a flaw in the making process. A crack that was formed in the making will have rounded corners, whereas a dunt is sharp.
Be aware that there is such a thing as delayed dunting. By discussing it with the potter, you may help him/her to solve a issue that they may be unaware of.

Links
TeachinArt - Online School of Art
Wheel thrown porcelain dinnerware
Handbuilding porcelain dinnerware
AIC_IAC - International Ceramics Academy of Ceramics
MAC - Mississippi Arts Commission

Antoinette appreciate any comments. Also visit her Porcelain shopping gallery if you are interested in collecting one or more of her ceramic art pieces.