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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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Fusion 360 drawing for glaze melt flow tester is available

We have promoted this device for many years as a way to compare glaze melt fluidity, surface tension, bubble retention, crystal growth and transparency. If you would like the 3D file please contact us. You can 3D print your own model and made a mold from that. There is no charge.

Wednesday 24th April 2019

Low fire ware cracking during firing. Why?

Most low-fire bodies contain talc. It is added for the express purpose of increasing thermal expansion. The natural quartz present does the same. These are good for glaze fit but bad for ware like this. You could fiddle with the clay recipe or change bodies, but better to change the firing schedule. ... more

Wednesday 17th April 2019

It is not the speed of drying, but how even it is

Half of these Plainsman Polar Ice mugs cracked. But I know exactly why it happened! After throwing them I put them on a slowly rotating wheelhead in front of a fan to stiffen them enough so I could attach the handles quickly. Of course, I forgot them and they got quite stiff on the lip (while the ... more

Tuesday 9th April 2019

Wanna throw porcelain plates with thick bottoms and thin rims?

Then they may need a week to dry! This plate had a one-inch-thick base (while the rim is a quarter of that). During the first few hours a thin rim like this will dry quickly, leaving the base far behind. But as soon as it would support the weight of a cover-cloth I put it into a garbage bag and ... more

Tuesday 9th April 2019

The fact that it applied like this was not worth mentioning?

Recipes trafficked online seldom include important information. How could the author of this one not mention this problem? The slurry turns to a gel and fills with bubbles. And then you have to add water again. The extra water makes it shrink more, compromising the bond with the bisque so it peels ... more

Tuesday 9th April 2019

GA6A Alberta Slip base using Frit 3124, 3249 and 3195 on dark body

The body is dark brown burning Plainsman M390 (cone 6). The amber colored glaze is 80% Alberta Slip (raw:calcine mix) with 20% of each frit. The white engobe on the inside of two of the mugs is L3954A (those mugs are glazed inside using transparent G2926B). The Alberta Slip amber gloss glaze ... more

Monday 8th April 2019

Plainsman iron red clays with rutile blue Alberta Slip glaze

Cone 6 mugs made from Plainsman M350 (left) and M390 dark burning cone 6 bodies. The outside glaze is Alberta-Slip-based GA6-C rutile blue and the inside is GA6-A base (20% frit 3134 and 80% Alberta Slip). That inside glaze is normally glossy transparent amber, but crystallizes to a stunning silky matte when fired using the C6DHSC schedule.

Monday 8th April 2019

The same body works well at both cone 04 and 6!

How is this possible? 15% Nepheline Syenite. The unmelted nepheline particles impose their higher thermal expansion on the fired ceramic. It is porous and weaker than stoneware but the glaze (Spectrum 700) does not craze and does not permit the entry of water (the mug is glazed across the bottom and ... more

Thursday 4th April 2019

Mother Nature's Porcelain Mug

Original File: RedMNP.mp4

Wednesday 3rd April 2019

The matteness this glaze develops is dependant on the cooling rate

This is the G2934Y matte cone 6 recipe with a red stain (Mason 6021). The one on the left was fired using the C6DHSC slow-cool schedule. The one on the right was fired using the drop-and-soak PLC6DS schedule. The only difference in the two schedules is what happens after 2100F on the way down (the ... more

Wednesday 20th March 2019

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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 (legacy, no longer supported)

What people have said about digitalfire

• I am working as production engineer in ... Egypt, I have learnt more from your site, nice to me to be a member. Thanks to you.

• Tony's site is really full of exceptional technical information.

• Your web is great!

• Thanks again, and again, as always, for your ever-so-helpful web pages.

• Many Solution Regarding Ceramic Problems Got From Your Website.Thank You Very Much.

• 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.

• I am very much appreciative of the work you are doing.

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What people have said about Insight-Live

• Thank you very much for creating these examples and explanations. I am getting a much better understanding for why Frits are so much better. Now that I am digging into InSight-Live and manipulating the chemistry, this documentation is the main place where I can find the facts and suggestions that help clear up my questions. Thank you for creating such a very practical and wonderful upgrade . The interface is so nice and even forgiving. Thank You Very Much,

• How amazing it is to have personal contact on such an amazing technical site and I can’t express my gratitude for your generous spirit.

• I am learning so much from your website, even after 33 years in business as a ceramic producer.

• Thank you for your incredible library of information. I have a background in QA (Six Sigma) and Biology so I genuinely appreciate the information you've made easily accessible.

• Your site is amazing and your videos too. Such an inspiration.

• Thank you very much for your website, as a amateur Potter I find it an incredibly useful source of information about all kinds of things pottery related and when I'm trying to make glazes for example I will often refer to your website for guidance.

• You have done more for the advancement of ceramic knowledge than anyone I can think of. Thanks again! The information you provide and the work you have done is invaluable. I can't tell you how many problems I have solved because of insight and the reference library! Thanks again for all of the help you have provided.

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