For Flux Sake
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.
Episodes
What happens when I rebisque my pots?
We love when our international friends call in and today we have a great question from Colombia. The gang talk about making vitrified clay with South American ingredients, the logistics of changing firing temperatures, and the effect of rebisquing a pot. CMW has a brand spanking new website, including a great new way to check out For Flux Sake episodes. You can also submit your questions for th
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
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
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
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
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 tha
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 NC
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 Pa
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
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 sp
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 p
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
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 P
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 Ma
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 an
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 cou
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
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 ForFluxS
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
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
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?
Why is the last 200 degrees of the firing the most important?
Do you fire your kiln fast or slow? And does it really matter? Today the gang answer a few listener questions about the relationship between temperature, glaze melt, and vitrification. They also discuss a class of clays out of the UK that vitrify at low fire temperatures. Have you checked out the new For Flux Sake Patreon? This is a great way to show your support and have access to discounted m
Why is my casting slip hard-panning?
Commercial casting slips are great for their convenience, but what do you do when your recipe hard-pans in the bucket? Today the gang talk about why hard-panning happens and how you can fix it. They also discuss making temp checks, the best bisque temp for commercial glazes, and the controversy around the sale of fake ceramic pigments. Have you checked out the new For Flux Sake Patreon? This is
Help my clay is plucking!
Have you ever had small pieces of an unglazed foot ring stick to a kiln shelf? This bummer of a phenomenon is called plucking, and today the gang talk about how and why it happens. They also answer a listener's question about increasing plasticity in halloysite porcelains and take a trip to Materials Corner to discuss the rumors swirling around EPK production. Do you have questions or need advice
Halloween Extravaganza with Lord Celsius, Wizard of Clays, and Copper Carb
Halloween is our favorite holiday at For Flux Sake. We can't get enough of the costumes, candy, and science! Join the gang this week as they answer listener questions about using wild clays in a community studio, washing dirty clay laundry, and the proper way to open a bag of dry ceramic material. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and yo
What are the do's and dont's of working in a community studio?
Joining a new community studio can be exciting, but also a little scary. Today the gang talk about how to be a good community member. They also answer listener questions about clay color changes, using tar paper in the studio, and where to start when you get your first potter's wheel. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be fe
How do you convert glazes to European materials?
Have you ever moved and had to convert your glazes to materials from a different continent? Today the gang talk about how you might do that along with why 'S' type thermocouples are the best for accurate firings. They also answer listener questions about upcycling large amounts of casting slip and solutions for handles that keep popping off. Do you have questions or need advice on glazes? Drop us
What's the history behind Orton cones' unusual numbering system?
Today's episode starts with a trip to Materials Corner where the gang talk about the likely end of a favorite Kaolin for soda firing. They also answer listener questions about the logic behind Orton cone's numbering system, the cause of scumming in clay, and the lowest temperature that it's ok to store clay. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail
Is the bacteria in reclaimed clay a problem?
To start the show Kathy shares about the research being conducted into vanishing historic lusters at the Harvard Art Museum. The gang also answer listener questions about material supply chains, the cleanliness of reclaimed clay, and why Matt and Rose went solar. 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
What makes a glaze have a wide firing range?
Have you ever wondered why some glazes have a wide firing range? Today the gang talk about this phenomenon, answer listener questions about adding stains to clay bodies, and discuss underglaze application. This episode also starts with a trip to Materials Corner along with a check in from a listener about the porosity of flower pots. Do you have questions or need advice on glazes? Drop us a line a
What defines low-fire ceramics?
We are back for season 5 of the show with a low-fire themed episode. Today the gang talk about a few parameters that define low-fire ceramics, as well as how de-airing pug mills work. They also start the show talking about the brand 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 si
How does a kiln sitter work?
Do you remember the joys of using a kiln sitter? Those mini cones were so cute until you dropped one in the bottom of a fully loaded kiln. Even though manufacturers have shifted to computer controlled models, sitters were a key part of electric kilns for decades. Today on the show the gang answer listener questions about firing a kiln with a kiln sitter and making your own decals. Rose also reads
How can you tell if a glaze is fully melted?
Today your favorite glaze experts answer a listener's question about judging the melt of an ash glaze, methods for wet mixing bentonite, and whether or not it's safe to use industrial dinnerware made before lead was regulated. They also open the show talking about why you should never crush encapsulated stains. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gm
Are metallic glazes similar to melted metal?
Have you ever wondered what makes a bronze glaze work? This week on the show the gang answer a listener's question about metallic oxides in glazes, and discuss the finer points of what makes a pinhole a pinhole. 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. Today's episode is brought to you by Cornell
Can you adjust a cone 6 glaze up to cone 10?
Have you ever found the perfect glaze, but it is formulated for a different temperature? Today the gang talk about adjusting glazes from cone 6 up to cone 10, and how you might tell if your kiln can handle going to cone 10. They also start the episode checking in about their summer plans. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could b
Does how tight a kiln is packed affect its final temperature?
Have you noticed how a tight kiln pack can slightly change your cones? In this week's episode the gang talk about why this happens, as well as answer a listener's question about firing a balloon inside of a ceramic sculpture. 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. This episode is made in memory
What does vinegar do to clay?
Have you ever wondered why vinegar is added to joining slip? This week on the show the gang talk about the use of vinegar in the studio and the absorption rates of blending reclaimed clays. They also answer a listener's question about glazing terracotta flower pots. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featured on an upcomi
Fluxed Up with Steven Young Lee
Get ready for a wild ride in the studio with ceramic artist Steve Lee! In this episode of our Fluxed Up series, we dive into the precarious world of ceramics filled with personal stories, studio mishaps, and the ever-elusive perfect glaze. Join us as Steven shares about his path to harnessing failure to create his beautiful porcelain forms, as well as his time as director of the Archie Bray Founda
Are ceramic sealers safe to use on functional ceramics?
Today we return to the much loved topic of glaze durability on For Flux Sake. Kathy, Matt, and Rose start by talking about the long term durability of Bristol glazes. Then they delve into listener questions about ceramic sealers and substituting for Gerstley Borate in Raku glazes. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featur
Episode 100!
Today we are celebrating the 100th episode of For Flux Sake! We'd like to thank the listeners for their excellent questions and for following along as the show has evolved over the last four years. To start this episode Kathy, Matt, and Rose share a few things they have learned making the show. They also answer listener questions about aging your glazes and single firing. Do you have questions or
Fluxed Up with Susan Feagin
Get ready for a wild ride in the studio with ceramic artist Susan Feagin! In this episode of our Fluxed Up series, we dive into the precarious world of ceramics filled with personal stories, studio mishaps, and the ever-elusive perfect glaze. Join us as Susan shares funny stories about working at the Penland School of Craft, as well as how she creates brightly colored slips for soda firing. Tune i
When do glazes actually melt during the firing?
Have you ever wondered when the magic happens during the firing? This week on the show the gang talk about the last 100 degrees C of the firing when glazes generally do their melting. They also answer a listener's question about thermocouples placement, and take a trip to Materials Corner to talk about Frit 3110. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@
Who are we?
This show has been going on for so long that the gang thought they should reintroduce themselves. Kathy, Matt, and Rose start the show talking about the experiences that lead them into a life of clay. They also answer a listener's question about calcining clay. 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 sh
Fluxed Up with Meredith Host
Get ready for a wild ride in the studio with ceramic artist Meredith Host! In this episode of our Fluxed Up series, we dive into the precarious world of ceramics filled with personal stories, studio mishaps, and the ever-elusive perfect glaze. Join us as Meredith shares about working with decals and layered underglaze, as well as how she had to pivot away from her favorite glaze in the middle of a
What should we know about cristobalite and quartz inversion?
Cristobalite and quartz inversion are the great boogie men of ceramics, often being used to explain cracking clay, glaze fit issues, and general ceramic mayhem. In this episode the gang sort fact from fiction and explain the changes that silica goes through during firing. They also start the episode talking about Matt's amazing new computer keyboard, which has beautiful celadon-glazed porcelain ke
Fluxed Up with Paul Andrew Wandless
Get ready for a wild ride in the studio with ceramic artist Paul Andrew Wandless! In this episode of our Fluxed Up series, we dive into the precarious world of ceramics filled with personal stories, studio mishaps, and the ever-elusive perfect glaze. Join us as Paul shares about making casting slips out of dark clay bodies, as well as how he builds with cast slabs for extra strength and durability
Are there budget-friendly black and purple glazes?
Have you ever tried to create budget-friendly glazes? It can be hard, especially when you want rich purples and blacks. This week the gang talk about ways to save money in your glaze lab, and how tariffs might affect the supply chain. They also start the episode commiserating on how cold it is this time of year in New England, and what to do if your clay freezes. Do you have questions or need advi
How can I measure thermal expansion?
Have you noticed thermal expansion measurements on your clay or glaze recipes? If so you might be wondering what those measurements mean, and how you use them to predict glaze fit on a clay body. This week the gang discuss thermal expansion and why those numeric values aren't always so helpful. They also answer a listener question about glazes with rare earth elements. Do you have questions or nee
How can I get the best firing out of my new kiln?
New kilns bring lots of excitement to the studio, but also a few questions. Should I calibrate my thermocouple? And, Do I need to adjust my firing rate to my new elements? This episode the gang talk about new kilns, ASTM standards for ware, and the difference between K23 and K26 soft bricks. They also start the show discussing testing methods for glaze durability. Do you have questions or need adv
Fluxed Up with Pattie Chalmers
Get ready for a wild ride in the studio with ceramic artist Pattie Chalmers! In this episode of our Fluxed Up series, we dive into the precarious world of ceramics filled with personal stories, studio mishaps, and the ever-elusive perfect glaze. Join us as Pattie shares a mishap with clay formulation, as well as how she teaches her students at Southern Illinois University Carbondale to be resource
What's up with all those pinholes?
Pin holes are a pesky issue in ceramics, largely because multiple glaze defects are often called pinholes. The gang talk about the myriad issues with pinholes, and if you can fix them on an already fired pot. They also discuss why commercial glazes have wide firing ranges. They start the show laughing and questioning the existence of removable ceramic stickers. Do you have questions or need advice
How can I make a speckled clay body?
Speckled clay bodies have come roaring back in popularity and in this episode our intrepid clay experts talk about what you can add to your clay body to create this phenomenon. They also talk about plucking and why potassium fluxes are best for clay bodies. To start the show the gang introduce the mysterious case of the A.I. glaze book. Do you have questions or need advice on glazes? Drop us a lin
Do I have to glaze my pieces?
Today's episode features a simple question. Do I have to glaze my pieces? The FFS gang talk about unglazed surfaces, and also discuss what triggers vitrification during firing. To start the episode, they also gab about Producer Ben's new book on low-fire glazes for potters and sculptors. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could
How do you make ceramic bakeware?
Have you ever wanted to bake bread in one of your pots? Today the gang answer a listener's question about the best way to make ceramic bakeware. They also discuss a new trend in environmental design and why using sodium fluxes in clay bodies can cause trouble when reclaiming clay. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featur
Fluxed Up with Osa Atoe
Get ready for a wild ride in the studio with ceramic artist Osa Atoe! In this episode of our Fluxed Up series, we dive into the precarious world of ceramics filled with personal stories, studio mishaps, and the ever-elusive perfect glaze. Join us as Osa shares her experience with letting go of a favorite glaze combo, and how this encouraged her to explore wild clay terra sigs. Tune in for a dose o
Bentonite versus Epsom Salts?
Do you have the hard pan blues when your glazes settle like a rock to the bottom of the bucket? The gang talk about how bentonite and Epsom Salts might solve hard panning, as well as when and how much you should use. They also talk about how to calcine a substance, and why you shouldn't calcine egg shells as a calcium source. This week's episode features the following topics: Bentonite, Epsom Sa
Why is this glaze so gloopy?
Have you ever mixed a glaze with the correct amount of water, but it still seems gloopy and thick? If you have then you might need to add a dispersant to help solve this issue. The gang talk about using dispersants, and they answer a listener's question about the robustness of cone six versus cone ten. They also return to Materials Corner to talk about the discontinuation of a popular luster brand
Why do pots get hot in the microwave?
Have you ever noticed how some pots get really hot in the microwave? The gang talk about why this happens, and answer a listener question about coloring reclaimed slop glaze. They also talk about glow in the dark glazes and Rose's recent video about them on the CMW YouTube channel. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be featu
Fluxed Up with Brett Kern-Happy Halloween!
Welcome to a very spooky edition of Fluxed Up with Brett Kern. Today we dive into the precarious world of ceramics filled with funny stories, studio mishaps, and the quest for the ever-elusive perfect glaze. Join us as Brett shares his journey with slip casting inflatable dinosaurs, using commercial glazes, and dealing with dunting after material changes. Tune in for a dose of humor, technical tip
How can we help North Carolina?
Have you wondered how you can help support artists affected by Hurricane Helene? This week's show is dedicated to sharing information and resources to assist the North Carolina clay community in rebuilding. The gang talks about assessing damage after a natural disaster, what supply chain issues we expect, and organizations needing support. If you'd like to contribute to disaster relief, please don
Are cone 6 soda fired pots durable?
Atmospheric firing is so much fun! What's not to like about a process where you get to spray soda into a flaming hot kiln. This week the gang talk about the durability of cone 6 soda fired pots, and the process for identifying mystery materials. They also take us behind the scenes to talk about what goes into making videos for the CMW YouTube channel. This week's episode features the following
What's so special about a Bristol glaze?
Have you heard of a Bristol glaze? This week on For Flux Sake the gang talk about the chemistry that makes these glazes work. They also discuss the crackle vs. crazing nomenclature, as well as the definition of porcelain. 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. This week's episode features the f
Fluxed Up with Lisa Orr
Get ready for the wonderful and hilarious ceramic artist Lisa Orr! In this episode of our new For Flux Sake segment Fluxed Up, we dive into the precarious world of ceramics filled with personal stories, studio mishaps, and the ever-elusive perfect glaze. Join us as Lisa shares her journey with making low fired white wares, the influence red iron oxide has on aventurine glazes, and her recent resea
Is that an Oolite?
Have you ever heard of an Oolite? Find out more about this rare and interesting glaze precipitate on this week's episode. The gang also take a trip to materials corner to discuss new potassium feldspars that could replace Custer Feldspar, and answer a question about kiln venting. Do you have questions or need advice on glazes? Drop us a line at ForFluxSakePodcast@gmail.com and you could be feature
The agony and ecstasy of Gillespie Borate
Join us as the For Flux Sake gang dive into layering glazes. Have you ever noticed some glazes look better below others, but not on top? Find out why the order you apply them matters and more on this week's episode. We also have a surprise visit and a great question about Gillespie Borate from their #1 superfan Kookie Kane. Do you have questions or need advice on glazes? Drop us a line at ForFluxS
Fluxed Up with Nick Sevigney
Get ready for a wild ride in the studio with ceramic artist Nick Sevigney! In this episode of our new For Flux Sake segment Fluxed Up, we dive into the precarious world of ceramics filled with personal stories, studio mishaps, and the ever-elusive perfect glaze. Join us as Nick shares his journey from porcelain skepticism to newfound appreciation, the impact of the Custer Feldspar shortage, and re
Shivering Sucks
We're kicking off Season 4 of For Flux Sake with a bang—or should we say a "ping"? Matt, Rose, and Kathy are joined by producer Ben to unveil some exciting surprises awaiting you in the new season. We're firing up a conversation about shivering, crazing, and all the unpredictable quirks that come with ceramics. Why is your glaze flaking off? Could your firing cycle or even hand sanitizer be the cu
Recommended
Conspiracy Files with Paige Carter
Bad Friends
Learn 50 English Phrases While You Sleep | Everyday English Phrases & Vocabulary
This Past Weekend w/ Theo Von
Dateline NBC
Back to the 80s Radio
Crime Stories with Nancy Grace
Bible Tea
این نقطه
TED Business
Dark Night Tales with Brian King
Fantasy Flex
