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For Flux Sake

Kathy King, Rose Katz, Matt Katz

Matt and Rose Katz of the Ceramics Materials Workshop and Kathy King of the Ceramics Program at Harvard University discuss listener questions about clay and glaze. This show will have you laughing and learning about the chemistry behind ceramics in no time.

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25 episodes
Avg 37 min
English

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S6 · E138
Yesterday · 34 min
Does it matter how fast my kiln cools?
We start today's episode with a trip to Materials Corner to talk about #1 Pottery Plaster. The gang also answer listener questions about converting celsius to fahrenheit and the cooling rates of kilns. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, Kiln Fire, Sheffield Pottery, Speed Ball, and Ceramic Materials Workshop's Ware Glazes. This week's episode features the following topics: #1 Pottery plaster, K-59 Georgia Pacific plaster, celsius, fahrenheit, cooling rate, kiln
S6 · E137
September 9 · 39 min
Can there be too much boron in a glaze?
This week's show starts with a discussion of a recent viral ceramic video and the merits of a potter dipping pots in water immediately after glazing. The gang also answer listener questions about the amount of boron glazes, melting in cone 6 mattes, and a safety concern from drinking out of a crazed mug. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Ware Glazes. This week's episode features the following topics: Boron, cone 6 matte, crazing, glaze safety
S6 · E136
September 2 · 36 min
How do I reassure customers that I don't use lead?
We start off season six of the podcast with a great question about customer service around ceramics. The gang answer a question from a paint-you-own pottery studio about reassuring customers that they don't use lead and using the full range of cobalt and copper sources that are available on the market. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, Kiln Fire, Sheffield Pottery, Speed Ball, and Ceramic Materials Workshop's Ware Glazes. This week's episode features the following topics: Season 6, paint-your-own pottery, lead, cadmium, cobalt, copper
S5 · E135
August 12 · 41 min
Why do cone 10 reduction glazes all look similar?
We start the episode with a quick trip to Materials Corner to hear good news about the mining of Red Art. The gang also answer listener questions about firing cone 6 clays to cone 10, finding vitrified commercial clays, and the aesthetic origins of cone 10 glazes in the United States. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Rhode Kilns, Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Ware Glazes. This week's episode features the following topics: Cone 10, Red Art, vitrified commercial clay, Materials Corner
S5 · E134
August 5 · 56 min
For Flux Sake Live in Boston!
For the first time ever the whole gang gathered in Boston for a live show at Harvard Ceramics. In this episode they answer listener questions about finding inspiration, altering glazes to fire hotter, dunting in plates, and the decomposition of iron in glazes. A very special thank you to Harvard Ceramics and the Harvard Ed Portal for hosting, and to the excellent questions the audience brought that evening. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Rhode Kilns, Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Ware Glazes. This week's episode features the following topics: Hard panning, epsom salts, inspiration, reclaim, plate, dunting, iron decomposition
S5 · E133
July 8 · 33 min
Do things ever explode in a glaze firing?
Today we have a special NCECA focused episode featuring questions recorded in person at this year's conference in Detroit. The gang answer questions about explosions in a glaze firing, sanding bisque ware, and wheel cleaning. They also start the episode taking a trip to Materials Corner to talk about changes in the Red Art supply. Thanks to everyone who stopped by the booth to record with us at NCECA. We can't wait to see you again next year. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Rhode Kilns, Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Explosions, sanding, cleaning, NCECA, materials corner, Red Art
S5 · E132
July 1 · 43 min
Do all glazes need Bentonite?
Today we have a special NCECA focused episode featuring questions recorded in person at this year's conference in Detroit. The gang answer questions about using hot wax, refiring in a community studio, particle packing for brushing glazes, and best practices for using Bentonite in glazes. Thanks to everyone who stopped by the booth to record with us. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Rhode Kilns, Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Wax, refiring, brushing glazes, particle packing, bentonite, NCECA
S5 · E131
June 10 · 40 min
The Cost versus Reliability episode
Today the gang compares cost versus reliability when buying kilns and kiln shelves. The episode starts with a question about purchasing S-type thermocouples for new kilns and a discussion about preventing warping in cordierite kiln shelves. On a related but strange note, they also talk about how a popular outdoor grill helped lead the U.S. into our current talc shortage. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Rohde Kilns, Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: S-type, K-type, thermocouple, cordierite, advancer, kiln shelf, Big Green Egg, talc
S5 · E130
June 3 · 36 min
Can I add something to a commercial glaze to change its temperature?
To start today's episode the gang talk about their upcoming live show in Boston. We hope you will join us June 5th at the Harvard Ed Portal, where Kathy, Matt, Rose, and Producer Ben will be ready to answer your burning questions about clay and glaze. They also answer listener questions about what to do when all your glazes mature at a different temperature, and how to identify a mystery white spot in the surface of your fired glaze. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Rhode Kilns, Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Live show, glaze temperature, Cone 5, Cone 5 ½, Cone 6, crystal formation
S5 · E129
May 13 · 38 min
Why do layered glazes look different every time?
Today we have a special Flux U episode where the gang dive deep into glaze application to answer a listener's question about the chemical and physical limitations of glaze layering. What seems like a simple topic turns out to be quite complex. They also talk about helpful tips for buying and installing your first home kiln. Have you ever wanted to be on a For Flux Sake episode? Join the gang in person for a live taping June 5th at the Harvard Ed Portal! Kathy, Matt, Rose, and Producer Ben will be in Boston to answer your burning questions about clay and glaze. Do you secretly need even more live shows? June 6th you can join a special Flux U taping at Harvard Ceramics. It's going to be a whole wonderful weekend of clay and glaze mania. Flux U, is an exclusive perk for Patreon members. If you'd like to have access to additional episodes like this one and special merch head on over to Patreon and join the For Flux Sake community. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Glaze application, kiln, electrician, particle packing, layering
S5 · E128
May 6 · 29 min
Can I use ash from a volcano in my glaze?
To start today's explosive episode a listener writes in wondering about using ash from Mt. St. Helens in a glaze. The gang also talk about best cleaning practices for keeping pets and children safe in a home studio, and methods for reducing pinholing. Would you like to ask your burning questions about clay and glaze to Kathy, Matt, and Rose in person? June 5th the whole gang heads to Boston for a live show. It's going to be a blast! Tickets are available now through the Harvard Ed Portal. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Ash Glaze, home studio, silica, silicosis, pinholing
S5 · E127
April 8 · 30 min
What materials should I buy to start mixing glazes?
We love questions from our educator friends. Today's episode starts with a question from a high school teacher who wondered what the best materials are for starting a glaze lab. The gang also answer a question about cleaning up clay with soap and take a trip to Materials Corner to report on the recent bankruptcy of a major ceramic materials supplier. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Glaze lab, beginner glazes, soap, Materials Corner
S5 · E126
April 1 · 34 min
Is it best to use the medium or fast fire setting on my kiln?
Have you ever wondered what the firing rates are for the pre-programmed kiln schedules in modern kilns? In today's episode the gang talk about the differences between slow, medium, and fast on Bartlett controllers, and how the rates affect glaze outcomes. They also answer a listener question from Sweden about Boron sources and why some of them were recently banned. To start the episode Rose and Matt also announce their exciting new adventure into the world of commercial glaze - Ware Glaze. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Firing speed, Bartlett controller, borax, boron, Sweden
S5 · E125
March 11 · 37 min
Why are my plates cracking?
Unloading a kiln can be an emotional rollercoaster, especially if it's filled with a new ceramic form that gives you trouble. Today the gang answer a listener question about how to keep plates from cracking, the best temperature for firing terracotta, and if there is a vegan alternative for shellac. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featured on an upcoming show. Are you coming to NCECA? Look for Matt and Rose at the Ceramic Materials Workshop booth and Kathy at the Harvard Ceramic booth in the expo hall. Hope to see you there. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Compression, particle packing, terracotta, low fire, shellac
S5 · E124
March 4 · 36 min
What causes carbon coring in clays?
What is carbon coring, and should we care about it? The term is actually a misnomer, with the real culprit being iron, a common ingredient in reduction fired clays. Today the gang talk about the phenomenon along with questions about kiln safety, and best studio practices for kids and pets. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featured on an upcoming show. Are you coming to NCECA? Look for Matt and Rose at the Ceramic Materials Workshop booth and Kathy at the Harvard Ceramic booth in the expo hall. Hope to see you there. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Carbon coring, red iron oxide, black iron oxide, reduction, stoneware clay
S5 · E123
February 11 · 33 min
Do I really need to sieve my glazes?
Glaze preparation is a necessary part of the ceramic process, but have you ever wondered why sieving glazes is important? Today the gang talk about various ways to prepare a glaze and why you might not need to sieve as much as you think. They also break down the idea of glazes that fire at multiple temperature ranges, and answer a listener's question about bubbling in a clear glaze. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featured on an upcoming show. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Sieving, bubbling, clear glaze, low fire, mid range, high fire
S5 · E122
February 4 · 38 min
Should I make my own clay?
To start today's episode we take a ride to Materials Corner to talk about the situation with EPK, as well as, if there is an easy substitute to use in clay and glazes. The gang also answers a listener's questions about the feasibility of making your own clay. What equipment do you need? Does doing it yourself save money? Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featured on an upcoming show. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: EPK, Materials Corner, clay mixing, pug mill, Pioneer Kaolin, Georgia Kaolin
S5 · E121
January 15 · 33 min
Do kilns really need peep holes?
Have you ever wondered why kilns have peep holes? Today Matt, Rose, and Kathy debate the function and necessity of peep holes, while also tackling a question about glazing only the interior of a pot. They also start the episode talking about the research Kathy is doing at Harvard Ceramics into the historic use of graphite as a ceramic sealer. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featured on an upcoming show. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Peep hole, kiln venting, glaze tension, glaze compression, dunting, vitrification
S5 · E120
January 8 · 39 min
Is there a difference between real and fake ash glazes?
Happy New Year! To start 2026 the gang answer listener questions about ash glazes, mixing brushing and dipping glazes, and how the particle size of colorants affects glaze outcomes. They also begin the episode sharing stories about the highs and lows of art center holiday sales. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featured on an upcoming show. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Ash, Fake Ash, colorant, particle size, holiday sale, brushing glaze, dipping glaze
S5 · E119
Dec 11, 2025 · 43 min
Gabriel Kline and Bill Collins on food safe glazes
Have you wondered what makes a glaze food safe? Today we are happy to welcome Gabriel Kline and Bill Collins to the show to talk about the topic, and their new book Amazing Glaze: Food Safe Recipes. They discuss the definition of food safety, how to test glazes, and what they learned after testing dozens of popular cone 6 and cone 10 recipes. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted merch, live hangouts, and extra episodes. Head over to Patreon and sign up today. Today's episode is brought to you by Monkey Stuff, The Rosenfield Collection, Cornell Studio Supply, and Ceramic Materials Workshop's Making Glaze Make Sense. This week's episode features the following topics: Food safety, leaching, crazing, cone 6, cone 10, shino, phase separation

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