Javascript must be enabled in the security or content
settings of your browser for this site to work properly

To learn more about cookies search for HTTP cookie at wikipedia.com





Click here for information about DIGITALFIRE Corporation

Tony Hansen's Thousand-Post TimeLine

I am the creator of Digitalfire Insight, the Digitalfire Reference Database and Insight-live.com. ... more

   All

Decomposing manganese granular particles in a buff stoneware causing it to bloat

A cone 6 stoneware with 0.3% 60/80 mesh manganese granular (Plainsman M340). Fired from cone 4 (bottom) to cone 8 (top). It is normally stable to cone 8, with the manganese it begins to bloat at cone 7. The particles of manganese generate gases as they decompose and melt, these produce volumes and ... more

Tuesday 23rd May 2017

Can you make a black-burning stoneware using black iron oxide?

Iron oxide has been added to a stoneware clay and samples fired at cone 6. They contain black iron oxide (10%, 5% and 2.5%). Even at 2.5% the raw pugged body is very black and messy to work with. Did they fire black? Or even dark grey? No. Some form of manganese is needed.

Monday 15th May 2017

4% iron oxide in a clear glaze. Unscreened. The result: Fired specks.

Iron oxide is a very fine powder. Unfortunately it can agglomerate badly and no amount of wet mixing seems to break down the lumps. However putting the glaze through a screen, in this case, 80 mesh, does reduce them in size. Ball milling would remove them completely. Other oxide colorants have this same issue (e.g. cobalt oxide). Stains disperse much better in slurries.

Thursday 11th May 2017

Redart (left) vs. Lizella clay. Definitely not substitutes for each other.

These bars have been fired at cones 4, 2, 02, 04 (top to bottom) using the SHAB testing procedure. We can measure fired shrinkage and porosity in each to get an indication of their fired maturity. The Redart (left) is much more vitreous and reaches almost zero porosity by cone 4 whereas the Lizella ... more

Sunday 7th May 2017

Stamp used for stamping information onto clay test bars

This type of stamp is deal for stamping mix and ID information on SHAB (and many other test types) clay test bars. Set up the run or recipe number on the left and the specimen number on the right.

Sunday 7th May 2017

These two frits have one difference in the chemistry: Al2O3.

These two boron frits (Ferro 3124 left, 3134 right) have almost the same chemistry. But there is one difference: The one on the right has no Al2O3, the one on the left has 10%. Alumina plays an important role (as an oxide that builds the glass) in stiffening the melt, giving it body and lowering its ... more

Thursday 20th April 2017

How to make a ceramic time-bomb

This mug is pinging loudly and literally self-destructing in front of my eyes! Why? The glaze is under so much compression (the inside is pushing outward, the outside inward). Spiral cracks are developing all the way up the side. Small razor-sharp flakes are shivering off convex contours. Why? I ... more

Sunday 16th April 2017

Example of how bubbles dissipate in a glaze with increasing temperature

This is a Gerstley Borate based recipe (45%) melted in crucibles at increasing temperatures. Although the recipe is well melted at cone 2, it is still not fluid enough to enable their migration in the time available. By contrast, the melt at the upper temperature is much less viscous, enabling all ... more

Sunday 16th April 2017

Ceramic Oxide Periodic Table

All common traditional ceramic base glazes are made from only a dozen elements (plus oxygen). Materials decompose when glazes melt, sourcing these elements in oxide form. The kiln builds the glaze from these, it does not care what material sources what oxide (assuming, of course, that all materials ... more

Wednesday 12th April 2017

Insight-Live comparing a glossy and matte cone 6 base glaze recipe

Insight-live is calculating the unity formula and mole% formula for the two glazes. Notice how different the formula and mole% are for each (the former compares relative numbers of molecules, the latter their weights). The predominant oxides are very different. The calculation is accurate because ... more

Wednesday 12th April 2017

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

Login to your online account

Chemistry plus physics. The on-line successor to desktop Insight. Get an account for as little as $15. It does so much more.

Conquer the Glaze Dragon With Digitalfire Reference info and software

Still available for Mac, PC, Linux

Interactive glaze chemistry calculations. Download it from the Files panel in your account at Insight-live.com (no extra charge).


How to reach us

From within your account at Insight-Live.com or

What people have said about digitalfire

• What a great site! Such a wealth of information. The thing I appreciate most about the site is the orderly and thoughtful and thought through approach to glazing. We are learning and earning potters, learning the craft and acquiring some income from it as we grow, working with cone 6 clays and glazes. I've been visiting your site frequently recently because we are starting to mix our own glazes, and we wanted to be able to incorporate the textures, surfaces and colors of our choosing, not hit or miss due to trying untold numbers of blind recipes. I've found that even a glaze that I've seen on someone else's work, using the same glaze mix on my work, does not guarantee the same result in my kiln, due to clay differences, surely, but also how my kiln fires, what temps it reaches, what timing, etc. So we want be able to work out glazes that look and feel the way that we like, in our firing environment, on our clays.

• I, personally, think Digital Fire's contribution to potters, and the Ceramic industry as a whole, is absolutely awesome, and I thank the gods there are people like you who have the knowledge and energy to provide us simple artist/educators with such exceptional tools.

• I found your site while looking up cone 10 glazes on google. I must say, it has been of significant help to me as i recently set up a workshop and am preparing to produce some pottery after 30 yrs. in the construction industry as a superintendent. Thanks for what you've done here...!

• After a lot of testing of various glazes I've decided he's overdue for sainthood.

• Your web site is wonderful. You guys are my knight-in-shinning-armor to slay that dragon. Learned more about glaze chemistry on your web page than in a graduate program at RISD.

• Very useful articles on practical solutions to the every day problems Ceramic Technicians face in their organizations.

• What an awesome list of videos you have here, and the info on your site is invaluable.

• I'm trying to access a great article on deflocculation. I have formulated so many casting slips over the years with the help of what I learned in that article and on this site.

• Thank you so much. This is what a good business looks like; great product, immediate response from the owner no less, and over the top service.

• I Everyday visit your website http://digitalfire.com. Fantastic knowledge you have....thanks .


To see more (at random) refresh this page

DigitalFire Logo

Privacy Policy