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Server Upgrade Feb 14-15, 2026

It has double the processing power and memory. Apart from speed, it enables ten times the number of active connections. Changes in our codebase also reduce load on the server. The firewall is now more robust at blocking bad bots and scrapers (while still allowing polite ones access), these have been the major load (they have exploded with the AI revoltuion of the past year).

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Tony Hansen
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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

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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

  • I've become fascinated with Glaze chemistry in the last year or so, have purchased your book, and refer to your site from time to time as well...What a great resource! I have read your book a couple of times, but have not completely digested all of it. I suspect it takes most folks quite a bit of time!
  • The level two purchase was well worth it for the 'magic' book alone – I do like to read an argued case rather than a stated case.
  • I want to also thank you for all you have done for the ceramic and pottery industry.
  • Your website has been very helpful to me over the past several years. I refer fellow potters to it constantly. Your G1214Z matte glaze formed the basis for the glaze used on my tea bowls.
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  • All your info on glaze chemistry and material characteristics are very informative and great catalysts for pushing me to take things a bit further. Most appreciated.
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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.
  • I am a long time admirer of your ceramics data base and teach at ... University.
  • I write to appreciate your good works by way of the articles you made available on the net .. Thanks a million for your good work. From Nigeria.
  • Your Digital Fire is so important in this community!
  • On a small aside. I want to thank you for all the work you have done over the years, firstly to inspire people like myself to see the technical side of ceramics as such a beautiful side of the art and not just a finished result that was lucky. And on that note with how much I read your blog, waiting for daily posts, reading all the old articles again and again, I see your mugs with the wheat grass on them all time, and was wondering if you ever put them up for sale. It's been an icon of my learning and would love to have one of the infamous mugs themselves.
  • Your information has really been a Godsend to so many challenges we have overcome. All of your efforts have really made such a HUGE difference in our studio, rarely is there a day where your shared knowledge directly or indirectly is part of my life. We are eternally grateful for what you have unknowingly (until now) done for us.
  • I just found your website, and am thrilled to see documented experimentation in ceramics. At 77 years old, I have taken up pottery and I enjoy every aspect. At the university I took courses through the 500 level, but never saw anything that approaches your site.
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  • Looking at your website, I have no doubts that there is no other person that would be so dedicated to the subject as you. It is a fact that you have a truly unique knowledge of how things are done, the materials and chemistry being used in such processes. Frankly, I do not complement people and their work easily but you are one of a kind person with some divine dedication to the technology. There are very few people like you and that is a fact. I just spoke with several so-called ceramics, frits and glazes experts and I have to say that they had somewhat limited knowledge while you cover incredibly wide spectrum of all affairs involved in to working with all those great materials.
  • I want to first tell you that your site is amazing. i love the approach, the attitude, and the incredible information. the fact that you share so much of your information to the public is truly wonderful. I recenly fell in love with ceramics and set up a home studio.

Blog

Step-by-step to do a formula-to-batch in Insight-Live.com

Insight-live does not automate formula-to-batch calculations, but it does assist in doing them. And it provides the tools to create an audit trail of test results, pictures and notes and a path to document subsequent adjustments. Along the way, you gain material knowledge and intuition. In this example, we derive the recipe of materials needed to source the oxide formula of a zinc clear cone 6 glaze (sourcing the oxides needed using a Ferro frit and other common raw materials). We'll create the target in a panel, start the batch in a panel beside it, supply the B2O3 from a frit and then the fluxes from feldspar, zinc and whiting. Then finish by rounding out the Al2O3 and SiO2 from kaolin and silica. The picture below shows the panels, the original target formula on the left and the final derived recipe on the right. The derived transparent glaze is on the inside of the mug and the outside is G3875, another zinc clear with iron and chrome added to produce the orange.

Context: How to choose ceramic.., Click here for case-studies.., A formula to batch..

Thursday 19th February 2026

Here is why Albany Slip was hard to use: Crawling

This glaze is 85% Albany Slip and 20% Ferro Frit 3195. These bisque tiles were dipped in a brushing glaze version of it (just water and powder). The glaze is applied quite thin on the front tile and thicker on the back one. The material gelled slurries and required a lot of water to make them thin enough to use. For assured success, this or any glaze that had a high percentage required mixing the raw Albany Slip with a calcined Albany Slip (which people had to make on their own).

Context: Albany Slip, Melt fluidity and coverage.., Shrinking glaze peeling glaze.., Six layers 85 Alberta.., Crawling

Wednesday 18th February 2026

A plastic pottery clay for rolling ceramic tile:

Not a crazy idea when it can do what this can!

This is the dolomite body recipe L4410P (a development version of Plainsman Snow). It is monoporosa tile on steroids; this body has zero percent firing shrinkage at cone 04! Predicting the final size and keeping that size consistent is much easier with such bodies. I have measured its drying shrinkage as 6% (doing our standard SHAB test). The final size needed is 20.5 cm square. Thus, I calculate the cut size to be 20.5 / (100 - 0.06) = 21.8 cm (or 20.5 / 0.94 = 21.8 cm). To keep these flat, we put them between sheets of drywall; the process takes 2-3 days. Since no change in size occurs during firing, this body has another big advantage: Tiles stay flatter during firing (a major problem with tile production). While making wall tile using a plastic pottery body is not something for industry (especially because of the space requirements for drying), for artisans working on a small scale, a body made by mixing super plastic ball clay with dolomite produces amazing working and tactile properties. The bonus is that they work so well at low temperatures, where there are so many glazing options.

Context: Monoporosa or Single Fired.., QRCode mounted on Plainsman.., Tile stacking in an.., Ceramic Tile

Tuesday 17th February 2026

Stains are better in black DIY glazes

Use 5% stain instead of 15% metal oxides

Make your own black glaze

Consider the hazards and hassles before choosing a black matte or gloss recipe that has high individual or combined percentages of manganese dioxide, cobalt or nickel.

Gloss blacks: These are super popular as the base for layering of reactive glazes. DIY dipping versions thus make a lot of sense. They make even more sense when they don’t turn to jelly in the bucket because of the high percentage of red iron oxide in all blacks made using metal oxide colorants. And when the total percentage of pigment is as high, or higher than 15%. And when the pigments cause crystallization (especially when overloaded).

Matte blacks: The human eye can detect even slight differences in the degree of matteness (which is very difficult to keep consistent). Raw metal oxides affect the matteness, especially when overloaded with pigment. They are prone to cutlery marking if too matte. By using stains, manufacturers and even potters have learned to tune recipes (lower left) and firing schedules to achieve consistency and functionality (even tourist souvenirs (lower right) feature them now). With stains, only one material is producing the color, its percentage (which can be as low as 4%) can be tuned.

Context: Ceramic Stain Toxicity Label.., Two cone 6 black.., Heres evidence that using.., Ceramic Stain, Toxicity

Monday 16th February 2026

This boron blue effect depends on three things:

A dark body, variations in thickness, the right chemistry

Boron blue on a black stoneware body

This is G2826A3, a transparent amber glaze at cone 6 on white (Plainsman M370), black (Plainsman 3B + 6% Mason 6666 black stain) and red (Plainsman M390) stoneware bodies. When the glaze is thinly applied, it is transparent. But at a tipping-point-thickness, it generates boron-blue that transforms it into a milky white. Glazes that are very glassy but on the edge of structural instability do this. So they are not good for functional ware.

This is an adjustment to the 50:30:20 Gerstley Borate base recipe (historically used for reactive glazes, often on functional surfaces! This cuts B2O3 and adds significant SiO2. But it still has double the boron of a typical functional glaze. While the chemistry of the original was within the territory of boron blue development (relatively low Al2O3), this one is better because of the increased SiO2 (the high MgO:CaO ratio is likely also helping). Boron blues like the lower Fe2O3 content or Gillespie Borate. One more factor: I am using 325 mesh silica here, it dissolves in the melt better.

Context: A pottery glaze that.., Boron Blue, Glaze thickness

Saturday 14th February 2026

I Tested a Found-Clay:

Was it suitable for pottery?

Would you like to be able to use your own found-clays, ones native to your area or even your property, in your production? Follow me as we evaluate a mystery clay sample provided by a potter who wants to do exactly this. I will use ordinary tools that any potter either already has or can buy at low cost. We will describe this clay in terms of plastic clay bodies and common ceramic materials that most potters already use. The potter who submitted it has worked enough with the material to suspect it has potential and he wants to know how to best utilize it (e.g. at what temperature, with what glazes, mixed with what, processed in what way). In technical terms what we are doing is called "characterization".

Context: Evaluating a clay's suitability..

Thursday 12th February 2026

Tile that is "actually HANDMADE"

This artisan, Dennis Cuku, is the king of DIY tile, making "actually HANDMADE" product using a red-burding terra-cotta-like middle temperature clay body. He also makes glazes in-house and fires using 36 shapes. He mixes 129 glazes and produces about 50,000 ft.² of tile per year. Tile making presents many unique challenges, not the least of which is the need for consistency and predictability of surface character and color. This endeavour is made possible with data, a lot of it. Not just glaze recipes, but many forming, glazing and firing procedures and techniques that must be documented.

Context: Potters can learn from.., An example of how..

Saturday 7th February 2026

Fine-tuning the thixotropy of a glaze or engobe

For dipping, this is so much better!

Watch this 30-second video to see. Gelled (thixotropic) slurries for dipping are so much better to work with; you'll never go back once you have mastered this DIY technique. While some glazes and engobes gel naturally, especially those with high clay content, these almost always work best when the water content is within a certain range, so fine-tuning like this is still needed. Although not shown here, if over-gelling happens, a drip or two of deflocculant (e.g. Darvan) brings back the fluidity, this is more likely to happen with engobes since they need more gel (for dipping and even more for painting). A side benefit of this: No settling in the bucket.

Context: Fine tune the thixotropy..

Wednesday 4th February 2026

Quick fix to make these spareless molds more usable

These legacy slip casting molds from Medalta Potteries (made from 80 year old masters). They are difficult and time-consuming to use and produce less than optimal results because they have no top section (this no spare) and require constant filling during cast time. Demolding requires cutting the lip flat (top right). But a lot of time trimming and sponging is needed to round it again, but making the lip even and symmetric is difficult to say the least.

I found a way to make these molds easier to use and better: A 3D printed spare/pouring spout that also defines a rounded rim. It can be glued to the top of the mold with slip. Of course, the PLA print is not absorbent, but this still works because the mold top edge is able to dewater the slip even inside the contoured top it forms. The print also acts as a cutting guide to cleanly cut anway any clay inside the spout section, leaving a clean line inside the lip. And the shrinkage of the clay pulls the pitcher lip away from the print.

Context: 3D Printed Pour-spout Forms..

Tuesday 3rd February 2026

The Heartbeat of the Kiln: The Indispensable Plant Technician

This page is dedicated to the skill and intuition of the Plant Technicians who kept the ceramic industry in North America thriving before the 1980s. Before we started clicking buttons to outsource things. They weren’t “role fillers” supplied by HR, they were “believers”. They understood everything in the plant; the equipment, processes, procedures, materials, recipes, kilns and firing. Managers set the pace, but the technicians made the pace possible. It was a time of local knowledge and company loyalty. They weren't temporary consultants or voices on a helpline; they owned and solved the problems. They were also mentors who passed their knowledge down.

These binders hold 40 years of recipes and techniques, kept by Albert E. Holthaus at Modern Art Products and Tierra Royal Potteries. Men like him were a legacy; they were the true "operating system" of a golden age of independence. They ensured the wheels kept turning, the fires kept burning and the quality kept enduring.

Context: Setting up a Clay.., Glaze calculation in the..

Monday 2nd February 2026



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