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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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Measure glaze specific gravity with a hydrometer? Forget it!

Measure glaze specific gravity with a hydrometer? Forget it!

Glazes need to be gelled, have thixotropy. That means these things won't bob up and down to find the right place. The one on the right is completely useless, the scale is too wide. Most glazes need to be between 1.4 and 1.5 specific gravity (40-50 on this scale). That is like reading seconds on the ... more

Wednesday 16th January 2019

Is this your record keeping system?

Is this your record keeping system?

Keeping your valuable notes like this? Recipes? Test results? Are your pictures lost in a cellphone with no keywords or connections to anything? If you test and develop you need to organize in a way that a book cannot do. Like link recipes to each other and other things like pictures and firing ... more

Monday 14th January 2019

Trafficked online recipes waiting for a victim to try them!

Trafficked online recipes waiting for a victim to try them!

Last week a customer came to buy materials to mix these recipes she found online. Then we had a closer look. Many have 50+% feldspar/Cornwall/nepheline with little dolomite or talc to counteract their high thermal expansion, these are guaranteed to craze. Many are high in Gerstley Borate, it will ... more

Monday 14th January 2019

Two G2571A Bamboo color versions at cone 10R

Two G2571A Bamboo color versions at cone 10R

These mugs are Plainsman H450. Both have a black engobe (L3954N) applied to the insides and half way down the outside during leather hard stage (the insides are glazed with Ravenscrag silky matte and G1947U over the black engobe). The bamboo glazes can thus be seen over the black (upper half) and ... more

Monday 7th January 2019

G1947U Clear and Ravenscrag Silky Matte glazes on L3954N black engobe

G1947U Clear and Ravenscrag Silky Matte glazes on L3954N black engobe

Fired at cone 10R. Clay is Plainsman H450. The black engobe was applied at leather hard stage. The clear glossy glaze over it on the inside produces a deep and vibrant hue. The black engobe extends downward on the outside and it greatly darkens the glaze applied over it. On the edges of contours, where the matte glaze is the thinnest, the engobe turns the color almost black.

Monday 7th January 2019

A vitreous sculpture clay. Vitreous enough for functional ware!

A vitreous sculpture clay. Vitreous enough for functional ware!

The chocolate brown burning super-plastic base clay (to which 20% coarse grog is added) matures at cone 6. Yet this is a cone 10R body. The grog stabilizes the fired matrix enough that it stands up in the kiln. And it fires to a dense product that can withstand any weather. Any porosity that can be ... more

Monday 7th January 2019

A cure for long-time Gerstley Borate sufferers

A cure for long-time Gerstley Borate sufferers

These are various different terra cotta clays fired to cone 04 with a recipe I developed that sources the same chemistry as the popular Worthington clear (50:30:20 GB:Kaolin:Silica) but from a different set of materials. They key change was that instead of getting the B2O3 from Gerstley Borate I ... more

Friday 21st December 2018

We fight the dragon that others do not even see

We fight the dragon that others do not even see

There are thousands of ceramic glaze recipes floating around the internet. People dream of finding that perfect one, but they often only think about the visual appearance, not of the usability, function, safety, cost or materials. That resistance to understanding your materials and glazes and ... more

Friday 21st December 2018

How much feldspar to using in a Grolleg porcelain

How much feldspar to using in a Grolleg porcelain

These are porcelains are made using Grolleg kaolin. P700 (Plainsman) has 19% G200 Feldspar and Coleman (popular among potters in the US) has 31% (P700 switches the 12% to kaolin). Although the Coleman porcelain is more vitreous (top right) it is not more translucent. But it is a lot more problematic ... more

Thursday 20th December 2018

The specific gravities on two commercial underglazes might shock you

The specific gravities on two commercial underglazes might shock you

AMACO and Crysanthos. 1.26 (67.5% water) and 1.22 (68% water)! The former is well below their recommended specific gravity of 1.4 (it still paints well but needs more coats, and more time to dry and apply them). Strangely, the Crysanthos, although having a lower specific gravity is more viscous and ... more

Wednesday 19th December 2018

Contact Us:

Use the contact pages within or outside your account at Insight-Live.com


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

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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

• Honestly I do not see how you have time to experiment, test, etc. and disseminate the massive amount of knowledge you have.

• 'we have been using the arabia blue and white variation of the 5X20 cone 6 glaze, and have had a great response from our customers. Thanks for your efforts - you have made a believer out of me!"

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

• I have been perusing through some of the level 2 areas of your site and am just in awe of what a great resource you have developed.

• Hi Tony, First, your website is the most knowledgeable and accurate information available on the internet today. THANK-YOU!

• As I read this I am thinking wow, what a great article, so useful and I love the details of the pictures.

• I love your site and am so grateful for all you have done to help with glaze formulation/safety.


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What people have said about Insight-Live

• It's very impressive work you do. Thanks you for providing it.

• Had quite quite a few problems learning to enter recipes.

• I want to first tell you that your site is amazing. i love the approach, the attitude, and the incredible information. the fact taht 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.

• Just read your page and I am awestruck!

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

• I wanted you to know that, you have a fantastic program. Every serious potter should use it. And it would be a good starting curriculum for high school and college to learn from. Thanks for, I would imagine, many hours in developing time. Kudos sir. I hope, by God's good will that I will be able to enjoy it for any years to come.

• You are due many complements on your site and software. I usually have your A - Z materials dictionary open in my web browser.


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