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Tony Hansen's Thousand-Post TimeLine

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

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Hand-tooled jigger model vs. 3D-printed and cast

I have a profile drawing I want to match (upper left). On the left is my first attempt to tool a model. Even though I attempted to jigger the plaster to match, the profile is way off. I lost the enthusiasm to even get it smooth. For the one on the right I 3D-printed a shell, poured the plaster in ... more

Tuesday 15th October 2019

Getting a 31 inch porcelain plate through drying and firing without cracks

What does it take? Three months! Porcelains are fine grained and, for heavy pieces, they will not tolerate uneven drying at any stage. These cone 10 plates are made by Peter Flanagan at Okanagan Pottery in Nelson, B.C. Firing is also a real challenge. Pottery porcelains are high in quartz, getting a ... more

Tuesday 15th October 2019

For even coverage white majolica glazes must be applied by dipping

The mug on the left has three coats of Spectrum Majolica base, painted on by brush. Drying was required after doing the inside coats, so the total glazing time was several hours. The glaze layer is way too thin and it is not even at all! The one on the right was dipped in a 5 gallon bucket-full of ... more

Monday 14th October 2019

Casting Zero3 Porcelain

Look at how translucent this is! I can fire one of these in three hours, cold-to-cold. I am casting them with molds made using the 3D-printing process. Anyone could do this. Incredibly exciting. And with the G3879 glaze it looks awesome, just like bone china. Notwithstanding this, the Zero3 recipe ... more

Monday 14th October 2019

This mug has waterlogged because it is not vitrified

Notice the water has wicked up to about 1 cm from the rim (the piece sat in water overnight). The glaze fits so there are no cracks for the water to seep through. However, being fired at cone 04, the body is quite porous. The piece has a unglazed base. Notice the water even travelled up the handle. ... more

Tuesday 8th October 2019

Two batches of EPK tested quite differently in 2018

The EP kaolin has been mixed 70:30 with nepheline syenite. This creates a body that matures below cone 6. And it enables comparing the degree to which the two kaolins influence vitrification (and their contribution to fired color in a vitreous body). The darker one is more plastic, has higher drying ... more

Monday 7th October 2019

By the magic of delflocculation, this powder will mix into that water and still fit in the container

This is 1100cc of water and 3000 grams of M370-2 casting. Amazingly, it is possible to get all that powder into that little bit of water. And still fit in the container (2250cc) and still produce a very fluid slurry for casting. How is this possible? That water has 11 grams of Darvan 7 deflocculant ... more

Friday 4th October 2019

Does a grog addition improve thermal shock resistance?

Pyrax (Pyrophillite) is a mineral having a very low thermal expansion. It stands to reason that if we can maximize its percentage in a body and not fire the body to a point that changes the crystal structure, it will be resistant to thermal-shock-resistant cracking. To that end I mixed it with only ... more

Friday 4th October 2019

What does it take to opacify a low temperature terra cotta glaze

Tin oxide is a powerful opacifier, but the 5% in the glaze on the left is clearly not enough. 10% more zircon had to be added to produce the one on the right.

Thursday 3rd October 2019

Frits vs. raw materials in glazes: It is not just about the chemistry

I have done alot of work recently comparing the sourcing of fluxing oxides from frits vs. raw materials. The differences are often incredible. The oxides MgO and CaO normally come from materials that melt high. But common frits that source them melt low. The chemistry in the two cone 6 glazes ... more

Thursday 3rd October 2019

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What people have said about digitalfire

• I have a background in Geology (BS-1973-New Mexico Tech), and with a few other degrees here and there - and have been doing quite a bit of Pythoning, and hanging-around my wife who does (I think (but then, of COURSE I am biased)) terrific pots... I am always interested in what she does with glazes (especially when I see the mineral-names from my Geology days on the bins in her studio... BUT - as an "engineer", sometimes I want 'more' knowledge - and I find your web-site VERY VERY good at that, it tells me a lot of things - gives me 'value added' and 'information' that I haven't found elsewhere! Especially when I think about 'geo-chem'.

• 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). Thank you for your wonderful contributions.

• I'm only just beginning to learn about pottery and glazing. I have learned more from your website than anything I have read!

• This is a excellent site for Ceramic colors and containing very good knowledge for Ceramic coloring agents. Thank to Digitalfire Ceramic Oxides Directory.

• You have such a goldmine of information available on your Digitalfire website and I am asking your permission to, not only use some of it, but to direct the students to your website for more info than I could ever convey.

• I am so fascinated by your site I have trouble to leave it!

• Firstly, I want to thank you about this very good site in the net which helps very much in the development of the ceramics industry.

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What people have said about Insight-Live

• Thanks so much this info is so great!!

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

• I'd just like to say that I love Digital Fire and I'm on here pretty much everyday. It has been soo helpful. Even though I am still leaning and exploring what I can do with the program it has been a huge help, and I believe it will be for years to come. I'm such a fan of your glaze software and tell all them members here .. what a tremendous asset it is to my practice.

• Sure do like Insight and I've switched to using the live version. It's excellent!

• I work at a small, but rapidly growing custom slip-cast studio. The first few years were a learning curve gauntlet that, in retrospect, I am surprised we exited intact. This preface is to give a sense of how in debt I am to your research and hard work. I have had to learn as I go along, and the information you provide at has been indispensable, and, quite frankly, an excellent cover for my ignorance on countless occasions! It is also the only source of information about many ceramics topics that I feel I can trust, knowing that it has been backed up with careful consideration and testing. Thank you again.

• Yet again, you provide a quick answer not easily found elsewhere (a bowl was befuddling me with wall cracks that never made it to any edges.)

• My glazes activities are seasonal anyway. In the summer i make pots in winter I think about chemistry and sit at a PC. I looked at your pricing again and it is indeed reasonable.

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