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Tony Hansen's Thousand-Post TimeLine

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

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A terra cotta body fired from cone 06 (bottom) to 4

Terra cotta bodies are more volatile in the kiln than stonewares. They mature rapidly over a narrower range of temperatures, that process is accompanied by dramatic changes in fired color, density and fired strength. These bars are fired (bottom to top) at cone 06, 04, 03, 02, 2 and 4. This is ... more

Friday 8th November 2019

Four north American ball clays fired to cone 10R, 11 and 10 oxidation

It is amazing now similar different ball clays are. Clearly, soluble salts are an issue with all of them (the brownish scum). These bars are much cleaner on the backsides (since the solubles were left on the surface on the fronts during drying). The drying shrinkages, plasticities and fired maturities are also all remarkably similar.

Thursday 7th November 2019

G2934Y glaze on Standard #112 body at cone 6

Produces an appearance very similar to dolomite-matte-glazed ware fired in cone 10 reduction. The effect would be similar using speckled bodies made by other manufacturers. Pieces made by Tom Friedman.

Thursday 7th November 2019

What has the trust in online recipes come to?

These tests of a recipe called "Strontium Crystal Magic". The potter tried it on different bodies and firings. But instead of producing the magic crystals like the pictures, the surfaces fired totally matte. Reasoning "why would anyone put a recipe on line that does not work", she blamed one of the ... more

Tuesday 5th November 2019

White stain. Does it work?

This is G2934Y matte glaze base with opacifiers added. It has been applied to a dark-burning body to demonstrate the comparative degrees of opacity. The stain is Mason 6700 white stain. While it does not opacify nearly as well as tin or zircon, it does produce a smoother surface.

Monday 28th October 2019

Is it possible to make a thin flat porcelain tile from a plastic pottery body?

Yes. The body is Plainsman M370 (~ 25 silica, 25 feldspar, 30 kaolin, 20 ball clay + talc to tune maturity). It is 3.8 mm thick fired (vs. commercial tiles at 5-7mm). It was rolled (in the plastic state) and dried completely between sheets of plaster board. Bisque and glaze firing were on an alumina ... more

Sunday 27th October 2019

Same body, same glaze, same firing. Why did one crawl?

The body: M370. Glaze: G2934Y (with added green stain). Firing: Cone 6 drop-and-hold. Glazing method: dipping (using tongs). Thickness: The same. The difference: Wall thickness. The one on the right was cast thinner so the glaze took a lot longer to dry (the bisque lacked sufficient absorbency). ... more

Sunday 27th October 2019

Over deflocculated vs. under deflocculated ceramic slurry

The slip on the right has way too much Darvan deflocculant. Because the new recipe substitutes a large-particle kaolin for the original fine-particled material, it only requires about half the amount of Darvan. Underestimating that fact, I put in three-quarters of the amount. The over-deflocculated ... more

Wednesday 23rd October 2019

Kiln Firing Curve Recorder - In Development

So many glazes appear as they do because of the firing schedule (especially the cooling curve). Imagine getting an awesome result out of a kiln and not knowing (or being able to replicate) the exact firing schedule that produced it. This device reads and records the temperature once per minute. It ... more

Wednesday 23rd October 2019

Low fire glaze with the Al2O3 and SiO2 of a cone 6 glaze

Look at how fluid G3879 is at cone 06 even though it has the Al2O3 and SiO2 of a cone 6 (or even cone 10 glaze)! It have found that glazes with lots of boron can tolerate amazingly high levels of Al2O3 and SiO2 and still melt very well. And they create many options to lower thermal expansion that ... more

Wednesday 23rd October 2019

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What people have said about digitalfire

• Thank you for your work on behalf of the betterment of pottery.

• I enjoy and appreciate your work very much.

• Wow. Thanks. That is so great. I also thank you for making so much material available on your web site. You obviously care deeply about the craft and teaching others.

• I have visited your site many times. We have the largest department in new england at the moment. I invited students to visit the school library to access your site directly for all its wisdom! You do far more good than you realize, fellow mud-diver.

• Again, thanks for building a website that has been very influential in how I look at ceramics in general, and that has been such a valuable resource to my work as a student, production potter, and chemist.

• 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.

• Your site is one of the most unusual sites I have encountered since I began exploring ceramics on the web. I am a student in a 2 year pottery program, and would like nothing better than to understand glazing from the very beginning of my career as a potter...It is pretty overwhelming. To tell you the truth, you almost come off as a Southern Baptist Revival Preacher the way you rant and rave against the "Dragon." It is what got my attention, however, and I appreciate the quality of your work, but it is very overwhelming.


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What people have said about Insight-Live

• I just want to say THANK YOU for this incredible database of information. Thank you, thank you, thank you!

• Thanks for the great application. I have removed GB from many of my recipes and I love learning so much about my glazes instead of just "going wonder how that glaze works". Your resource is invaluable. I will be a lifetime member.

• The knowledge and information you share on digital fire is a rare gem on the internet. I greatly appreciate your writing style. To the point and full of facts. I am wanting to be more active in my glaze creation and begin to make my own glazes. This, to me seems like a huge step away from the safe and what I know of the glazes I have been working with.

• I have to say as the subject says i am completely blown away by the amount of valuable information I have just taken in over around 4 hours or reading through your vast content and watching your videos on youtube! I am now a big fan and will for sure sign up with an insight live account as soon as I can!

• Tony, I looked at Insight Live today more carefully. It is quite an accomplishment! Congrats to you!

• Hey Tony, just like to say thanks for your fantastic site as it has been the best reference guide for my helper and I.

• I join others (I'm sure) in thanking Tony for the incredible resource that is the digital fire library, and for the insight glaze calculation software and now website. Not a week goes by when I don't use all three of them and usually quite extensively.


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