Understanding Pottery Chapter 19 Glaze Defects

Welcome to Understanding Pottery, Chapter 19: Glaze Defects.
There seem to be so many ways that bad things can happen to good pots. Defects in fired ceramics can originate with the clay, the glaze, as well as the actual firing process. This episode we’ll discuss glaze defects that occur during the firing.
The next topic in the series is Pottery Myths, Errors and Misconceptions.
Understanding Pottery is a series in production by Washington Street Studios. The video series is a digital textbook that will take you through the entire ceramic process from the raw material through the finished ceramic pieces. There are five sections and twenty-six chapters planned in the series and they are:
Section I: The Pottery Making Sequence
Chapter 1: What is Clay?
Chapter 2: Clay Properties and Drying
Chapter 3: Bisque Firing
Chapter 4: Tips for Successful Glazing
Chapter 5: Pyrometric Cones
Chapter 6: Glaze Firing
Section II: Use of Raw Materials
Chapter 7: Chemistry for Potters
Chapter 8: Glaze Chemistry
Chapter 9: Oxides, Washes, Underglazes and Stains
Chapter 10: Geology for Potters
Chapter 11: Use of Local Materials
Section III: Kilns and Firings
Chapter 12: Atmospheric Firings
Chapter 13: Wood-Fired Kilns
Chapter 14: Gas-Fired Kilns
Chapter 15: Electric Kilns
Chapter 16: Raku Kilns
Section IV: Solving Problems
Chapter 17: Kiln Performance Problems
Chapter 18: Clay Body Defects
Chapter 19: Glaze Defects
Section V: Practical Applications
Chapter 20: Pottery Myths, Errors and Misconceptions
Chapter 21: Thixotropy, Quartz Inversions and Other Pottery Mysteries
Chapter 22: Pottery and Physics
Chapter 23: Pottery Figurin’ (Math)
Chapter 24: Personal Safety with Pottery
Chapter 25: Critiquing Your Own Pottery: Design Principles You Can Use
Chapter 26: Tips for Buying Used Pottery Equipment

At Washington Street Studios, we believe the sharing of creative energy and knowledge will improve the quality of our art and increase the appreciation of art within our community. We are striving to create an environment where the arts are shared and appreciated. We want to grow as a family of artists and contribute to our community. This podcast is one of our steps to share our passion for the ceramic arts, creative energy and knowledge with other artists and art lovers.

We also created an audio version to expand our audience. If you are looking for the podcast of our show search for the ‘The Potters Round Table’ on your podcast platform of choice.

[mjcomiskey]

This is by far the best tutorial I have ever seen on glaze defects. My thanks! I am very sorry to learn that Mr. Berneburg has passed away. What a great loss for the pottery community. I am hoping that someone in his circle could help me. I am wondering a substitution of Frit 3134 for Gerstley Borate is a 1:1 substitution. Thanks in advance.

[octaviaengres]

I really love his sense of humor and teaching skills. God bless you, Mr. Phil.

[ACUPOINTKAT]

I am still in deep dark forest but I lern a lot here. Thank you. Sending love, Kat.

[miniarora]

Very new to ceramics and finding this so useful. Sad to know Mr Berneburg is no longer with you us. If anyone can help me understand why one of my items with clear glaze crazed and yet others in the same firing with same clay didn’t. It was a large flat piece so bit different in shape.

[kadensmike]

A treasure box of useful advice! Thanks.

[creepycuteceramic]

I don't understand why there are not so many likes but many views. Mr Phill deserves all the love♥️

[wendythompson]

Thanks very much Phil for sharing all of your years of knowledge. You explain things so clearly.

[christinecook]

such a thorough, brilliant tutorial. Thank you so much!

[ryangreene]

Fantastic content. First time watching. You’ve got yourself an avid fan instantly.

[pollyannwhite]

Thank you so much. You answered at least three of my queries regarding glaze problems. Hope all is well over there. Very best wishes from the East Riding of Yorkshire, England.

[raineboots]

I watched this after picking up my failed glaze fired pieces. Thank you so much for sharing this information. I’ve learned so much!

[plantspresents]

Best resource I found 🙌🏻 thank you! 🙏🏻

[michellestarnes]

Thank you for taking time to explain everything! I'm a newbie that kinda just jumped in lol. I'm loving your videos!

[eucalyptustrees]

This series is really helpful. Thank you to all involved in making these videos!

[stuhaysman]

Brilliant and hugely helpful - having just tested a new clear glaze recipe and ended up with a milky bubbly mess!

[weedayna]

I am a polymer clay artist who is considering switching to ceramic. The amount of challenges with ceramics is so daunting. I make detailed sculptures and I cannot imagine even one of them getting ruined beyond repair. I would be so heartbroken. It makes me not want to bother with ceramics at all. Thanks for the informative video. I got a lot to consider

[JulianaSilvaCamargo]

This video is so good, i na from brazil and it helps me a lot, thank you

[sofiabernardo]

very useful video so well explain! the best to be aware of every thing so defects can be reduce but i wish there was another with how to fix the defects after they ocurred😂. like if there was a overfired is it possible to refire and remend the default?

[piipottery]

Excellent video!!! Phil, What possible solutions do you find for delayed crazing? I work with earthenware clay

[deepashtray]

In my limited experience crazing is a great deal more prevalent in clear glazes. I'm hypothesizing that this is due to the glaze shrinking as its ingredients are cooked off. In my last firing one glaze did fine totally opaque at cone 6, but as the temp increased (I have a very hot bottom shelf) to the point where it becomes clear glossy glaze it crazes... a lot. Did this on 2 separate glaze recipes in this same firing.