Click here for information about DIGITALFIRE Corporation

Monthly Tech-Tip from Tony Hansen

I will send practical posts like these (from thousands I maintain). No ads or tracking. We are troubleshooting the confirm email, for now you will be subscribed immediately (the first monthly email will provide one-click unsubscribe).


Blog

Danny Downsized: He's Being Outsourced.

He should have seen this coming!

Management now thinks they can outsource his technical work. Danny was good, but he didn’t build a centralized, searchable record of material testing, shipment histories, specs, production problems, and solutions. Instead, his knowledge is buried in thousands of Excel and Word docs and PDFs. He should have used Insight-Live.com to organize, interlink, and preserve this critical data. Sadly, the company does not even realize what they face without Danny:

  • Slower problem-solving and loss of institutional memory.
  • Greater dependency on outsiders who lack long-term investment.
  • Inability to verify product claims.
  • Quality drift leading to recalls, rework, and higher warranty costs.
  • Innovation slowdown.
  • Eroding customer trust and ballooning consultant costs.

Had Danny been not just a watchdog but a technical innovator, suppliers and consultants would have been secured to support—not replace—his in-house expertise.

Context: Protect your reputation as.., 2 Skids of Material.., Tommy Turnback Ignored AI..

Sunday 31st August 2025

Tommy Turnback Ignored AI

By not adapting he wrote his own layoff notice

Tommy Turnback Is being laid off

Management says AI can do most of the technical work now. Tommy had no automation, no models, no data pipelines. Just “the way we’ve always done it,” trapped in spreadsheets and sticky notes. When the new AI system went live, his expertise didn’t plug in. It got left behind!

  • The AI could really have used his seasoned human oversight.
  • Years of hard-won knowledge lost in a digital junk drawer.
  • Outside consultants are charging a premium to relearn what he already knew.
  • Errors slip through because no one taught the machines better.
  • Innovation stalls while the company rebuilds what he could have bridged.

Technicians aren’t just there to keep things running—they should teach the future how to work. Refusing to adapt doesn’t protect your job. It writes your own pink slip.

Context: Danny Downsized He's Being..

Sunday 31st August 2025

Picasso’s Transparent Glaze

Micro-bubble free and crystal clear

Picasso low fire plate clear glaze

This plate, by Pablo Picasso, is on display in the art gallery on our Princess cruise ship. While others notice the underglaze designs, and the $40,000 price, I notice the absolutely crystal clear and bubble free transparent over glaze. How did he do that? At the Madoura studio they used leaded glaze, so Picasso himself doesn’t get the full credit. By his time, European low-fire traditions already had a well-matched clay/glaze system based. Glazes were made from mostly lead bisilicate frit with enough kaolin or ball clay to suspend the slurry. The lead melted so well that significant silica could be tolerated (20–30%) to reduce the COE. They didn’t use talc in the body, rather it would have contained 50-70% ball clay/kaolin, some feldspar as a filler (since it does not flux at low fire) and enough quartz to raise the thermal expansion within the range of the glaze.

Most potters struggling with borosilicate glazes would envy what leaded transparents can do. Any hope of even approaching them using boron glazes lies in keeping temperatures at or below cone 06, a thin glaze application, a low carbon body and ceramic stains rather than metal oxide colors.

Context: Lead bisilicate with his.., UK Slipware A Tradition.., Transparent Glazes

Thursday 21st August 2025

Glazing For the Photo Instead of the Pot.

Is it a “science project” or a functional glaze?

A runny reactive pottery glaze

This is a reactive pottery glaze, Jen’s Juicy Fruit. It runs. And crystallizes. That can look great on a test tile but for food surfaces there are strings attached. Behind the magic a tangle of headaches can be lurking: Leaching, crazing, poor durability. And even expense (this kind of melt fluidity usually requires wallet-busting lithium). But hey, why not go for it! Stuff it with metal oxides and get some real sparkle brewing. Then push it even harder, with slow cooling, for those big crystals. Congrats, now you’re brewing a science project. And flirting with leaching and toxicity. And there is more. These effects most often depend on high sodium or potassium (aka high feldspar), that’s a recipe for off-the-charts thermal expansion - and thus crazing. Is this glaze something you would want on a food surface? Suddenly that “wow” glaze starts to look… not so wow.

Hey, why not just fix it? Reduce that high KNaO, increase the SiO2 and Al2O3. Congrats. Now it looks totally different. And boring! With these types of glazes it is common that no matter what you do, you cannot maintain the character while fixing the problem. Why? The visual character depends on the problems! So use this. But not on functional ware.

Context: Reactive Glazes

Wednesday 20th August 2025

“Retail Rick” Has it Figured Out

He’s got a much better way to glaze

Rick doesn’t dig clay, crush rocks, or make glazes. Ew, messy. He buys commercial glazes in cute little jars, each the price of a steak dinner. Sure, back in the dark ages, potters used actual dirt and rocks. And, around here you can even get a ton of gravel or clay, for $20. But today, potters shell out twice that for one box and say, “Totally worth it!” OK, fine. But glaze is where it gets magical. A ton of local gravel is packed with feldspar, silica, calcium carbonate, dolomite — a whole cone-10 party (that can be moved to a cone 6 neighborhood with a little frit). Grind it, add clay, dip, done. How is it possible that an overloaded pickup truck full costs half the price of a single 500ml jar Rick uses? Something’s upside down here! Rick says: “Why mess with base recipes or spend all that effort learning and testing DIY dipping glazes when I can spend minutes multi-layering these commercial paints”! Of course, he has to brush up the price to pay for them! And sure, some customers might question how glazes that have such intense metallic colors and run like mascara in the rain are not silica-starved metal-oxide sludge. Rick answers: “They have safety labels, with fancy symbols, so I don’t have to think about that”. The icing on the cake it how well they photograph and how good they look on Rick’s social. He really has this thing figured out. Tradition is overrated anyway, right?

Context: Are drippy glazes what.., Commercial hobby brushing glazes..

Sunday 17th August 2025

Somehow the Gerstley Borate 50:30:20 glaze worked.

But does it work using Gillespie Borate?

Gerstley Borate glaze is jelly

This recipe, G2826A, a base transparent recipe having 50% Gerstley Borate plus 20% kaolin, is "jelly city". Although a low temperature base, this was much more commonly used at cone 5-6. This recipe, G2826A, was at the limit of how melt fluid a glaze could be. And at the limit of the slurry properties that could be tolerated with this material. In this test, even with 2.5g of Darvan deflocculant in this jar, it was still thick enough to require pushing this tile down into it! It still needed 5 seconds to build up enough thickness. And did not cover the recesses properly. Yet people have used this popular fluid-melt recipe for 50+ years to get the surface variegation it produces (because of boron blue) and the fluid melt (because it is so high in boron). They added all manner of colorants and opacifiers and it generally performed without blistering. The melt fluidity required careful control of thickness (to avoid it running onto shelves). This was a "Dr. Jekyll and Mr. Hyde" of ceramic materials!

Potters are using Gillespie Borate in this recipe (with issues), see the G2826A2 recipe. Other approaches are to source the boron (B2O3) from a frit (or mix of frits). An example is G2826A1, it does not variegate as much but added titanium or rutile can emulate that. Another hybrid option is the G2826A3 that employs both Gillespie Borate, nepheline and talc.

Context: Gerstley Borate, Gerstley Borate 5 3.., Gillespie Borate is doing.., Cone 6 transparent way.., Replacing the Gerstley Borate..

Sunday 10th August 2025

A Super Plastic Stoneware Made With Two Materials

This mix showcases stoneware's advantages over porcelain

Feldspar/ball clay stoneware fits glazes, porcelain does not

Left: 65% #6Tile kaolin and 35% nepheline syenite. Although it has great plasticity and fires white, it crazes the glaze and has 1% fired porosity (using the SHAB test).
Right: 65% M23 Old Hickory ball clay (similar to OM#4) and 35% nepheline syenite (feldspar would also work). The glaze fits, the body fires very dense (zero porosity) and plasticity is fantastic!
The body on the left needs a 20% silica addition (to stop the crazing) and more nepheline (to reduce porosity to porcelain levels). The remaining 40% kaolin will not be nearly enough for a workable plasticity (so bentonite will be needed). The body on the right does not need fixing; it works as is. Many feel that stoneware body recipes must be built on a feldspar-containing base clay having pottery plasticity (adding ball clay, kaolin, feldspar and silica and ending up with needlessly complicated recipes). But, ball clay is a base, all it needs is a non-plastic filler (to cut plasticity and therefore drying shrinkage) and a flux to vitrify it - feldspar or nepheline fills both roles.

Of course, this stoneware does not fire as white. But do you need white? Glazes will fire brightly colored on this surface. And, cleaner ball clays are available in many areas (even ball clays intended for casting will be plastic enough). It is also worth considering the use of a white engobe.

Context: Ball Clay, Formulating a body using.., Stoneware, Porcelaineous Stoneware

Thursday 31st July 2025

v2 Digitalfire Mold Natches in OnShape

These are even better than before

Available on the Downloads page

3d printed mold natch system

Until now, I have done these in Fusion 360. But in OnShape and my new dimensioning method they are even better. If you are a hobby maker like me, then OnShape is free. This updated design only has three parameters: ID (inside diameter), OD (outside diameter), and slack (addition or subtraction for a good fit).

Print all four of these at the same time. Repeat cycles of adjusting the slack parameter and printing again until they fit into and over each other well (the better quality your printer to smaller the "slack" dimension can be). Print them in multiples of seven: Two natches, two embeds, two clips and one spacer (these are the proportions in which you will be consuming them).

An advantage of OnShape is that it enables sharing; the link is below. To 3D-print it select all four, right-click on one of them, export to 3MF format, open that file in your slicer software, position (and replicate/orient items), then print or export to a G-Code file.

Context: v1 DIY Four-Part Mold.., Glue-sticking the 3D printer.., Standard 3 8 inch.., 3 8 mold natch..

Saturday 26th July 2025

My Breakup with Fusion 360

I had a "Little Dictator", now I have a "Partner"

Two slip casting molds, one in Fusion 360, one in Onshape

I am just a simple guy, a hobby 3D printing "Maker", I focus on making molds for ceramic slip casting. I don't need a "high maintenance" CAD partner.

Fusion 360 and I were not a good match. It was her world, Windows and Mac only - I had to live in it. She was the “Queen of Complicated”, always on the drama channel of new features far beyond what I needed, rather than refining the simple ones I did need. And she was expensive to take out, costing way more than what I needed ($750/year).

OnShape is my new chill. She will go out, at full power, to Linux and iPad. She's a keeper. I don’t need a user manual for her. She's not a princess but a partner, social not a snob. I don't feel like I am on a roller coaster without a seatbelt, rather I am with someone that is easy to be around and way more powerful than she looks.

Context: OnShape CAD is Free.., Drawing the Same Mold..

Thursday 17th July 2025

3D Printed Pour-spout Forms a Rounded Lip

First date with OnShape went great!

This 3D-printed PLA pour spout potentially increases the utility of this one-piece plaster mold. As can be seen on the upper section analysis, the spout is designed to form the lip of this small Medalta Potteries bowl (and provide a guide for cutting its inside edge). It has lugs that extend outward to enable holding it down using rubber bands. I intend that it will be cleanly removable after the piece begins to pull away from the mold, leaving a high-quality lip that only needs a little trimming. This spout also permits precise monitoring of when to pour out the slip and it prevents most of the mess made using traditional molds having a spare.

This is the first piece I have made wholly using OnShape CAD. Experience with Fusion 360 gives me expectations of how this should work and those expectations are generally being met. Cost is no longer an obstacle to adopting professional 3D CAD for mold making. I am using OnShape on my 2014 Mac Mini running Ubuntu Linux (on 16gb RAM). And Prusa Slicer, OctoPrint, GIMP, Kdenlive, InkScape and productivity software are all running smoothly on it.

Context: OnShape CAD is Free.., OnShape parametric cloud-native CAD.., Drawing the Same Mold..

Sunday 13th July 2025

Contact Me

Use the contact form at the bottom on almost all the pages on this site or let's have a together.

Other ways to Support My Work

Subscribe to Insight-Live.com. It is about doing testing and development, not letting the information slip away. Starts at $15 for 6 months.

Help Me on Social

Tony Hansen
Follow me on

Test, Document, Learn, Repeat in your account at insight-live.com

Login to your online account

Chemistry plus physics. Maintain your recipes, test results, firing schedules, pictures, materials, projects, etc. Access your data from any connected device. Import desktop Insight data (and of other products). Group accounts for industry and education. Private accounts for potters. Get started.

Conquer the Glaze Dragon With Digitalfire Reference info and software

Download for Mac, PC, Linux

Interactive glaze chemistry for the desktop. Free (no longer in development but still maintained, M1 Mac version now available). Download here or in the Files panel within your Insight-live.com account.


What people have said about Digitalfire

  • You are world famous consultant & that is why asking your opinion in details about above (best solution from production quantity, quality & optimal cost).
  • I used Boraq 3 as I wanted the layered action and for the first time, I GOT IT. Thrilled is an understatement. I used the boraq 3 formula in the floating blue receipe and it's wonderful!!!!! My 2000 gram test was encouraging and the 4500 gram test looks great. I've glazed only a few test pieces with larger ones going in later this week. Right now I am one happy campette.
  • Also, as a side note, this website is an excellent resource and I appreciate the fact that all this info is available on the web! Not only that, but I have found the information to be accurate, dependable and thorough, which is difficult to find anywhere.
  • As a new potter, your website has been an incredible source of information for me, both in tips, recipes and things to ponder. I know I can speak for a few others when I say please keep posting as the information is highly valued.
  • Being new to this I was fascinated by the amount of information contained on your website and impressed by what you are willing to share.
  • I have not been pottery long and I have decided to try to make my own glazes. Your web site is great. I like your cone 6 base glaze.
  • I have had previous communication with you Tony, and want to say that you do a great job. Very informative. All of my former students are aware of your expertise.
  • Your Magic of fire was a waker upper, had to read it a few times this past few months just to give my head a shake. Yes, I am having crazing issues, and its past time to get away from Gerstly Borate. Just purchased numerous frits and actual commercial stains. After 30 years in the biz, I am going to do this!
  • I have the downloaded version of The Magic of Fire for several years now and find it excellent. I'm now ready to purchase level 2 of Insight. Your resources are truly amazing and as an ex electronic engineer (now a potter), I really am impressed with your analytical approaches. Your site is almost a complete college level course on pottery (less the throwing & handbuilding).
  • I love the site. I use it all the time at the Clay Business, and I feel like I have not even touched the surface.

What people have said about Insight-Live

  • I have been following your Site and posts continually and gained a greater understanding. Thank you for that. It is so exciting to have a positive outcome from your glazes rather then the bought glazes. ... All good and exciting. My pottery clients are excited and have recognized the difference. There is nothing better than to pass on the best work possible to those who love the pots. So much work and testing, but well worth it. Thank you so much.
  • Superb. Very interesting study (about frit melting behaviour). Wow. What a patient effort!
  • If you didn’t know yet (most people don’t really express how they feel so I’m talking on behalf of the whole pottery community), you have become our most trusted & valuable ‘all things pottery’ resource. Thank you for your time, and the wisdom you share with all of us. I’m a humble newbie and i want to tell you how much I rely on the information you post and how much I appreciate everything you do. I want to name you ‘the clay angel!’.
  • I've said it before, but I can't say it enough, thank you for all your work on digitalfire and insight.
  • Your site is a crucially important one, and I'm happy to help you, even in small ways.
  • I wanted to let you know that I greatly appreciate all the knowledge you have shared with me over the years. Its made an enormous difference in the quality of my work.
  • Hey Tony, thanks so much for developing such a useful software. I have come to digital fire for countless questions I have had with clay and glazes.
  • I appreciate all you do for the ceramic community. I follow and read all you put up, someday I pray for a better understanding of glazes and all that encompasses.
  • I have really been enjoying using insight.
  • I don't know who you are but you are 100% awesome. I didn't know anything about glazes and clays but then I stumbled upon your site and it is a gift to the world. I wanted to thank you.



https://digitalfire.com, All Rights Reserved
Privacy Policy

1