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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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Precipitate can forms in fritted glazes, remember to screen it

Precipitate can forms in fritted glazes, remember to screen it

Potters often store glazes for long periods so tiny spherical precipitate particles can form. These were found in a months-old bucket of G2926B (M370 clear) cone 6 clear glaze (about 2 gallons). These can appear over time, depending on factors like temperature, electrolytes in your water or ... more

Saturday 16th June 2018

G2926S low expansion cone 6 base glaze is here

G2926S low expansion cone 6 base glaze is here

G2926B has proven to be my most durable, crystal clear, non-crazing, easy-to-use general purpose cone 6 base glaze (from dozens I developed). However, some porcelains (e.g. Plainsman P300) need an even lower thermal expansion. G2926S adjusts "B" (by adding low-expansion MgO at the expense of ... more

Saturday 16th June 2018

What happens if Ravenscrag Raspberry is applied too thick

What happens if Ravenscrag Raspberry is applied too thick

These are Plainsman P300 mugs fired at cone 6. When the glaze, GR6-E, goes on too thick (as on the left) it is dark maroon and has a pebbly surface that does highlight contours. This went on too thick because the specific gravity of the slurry was too high, about 1.53 (even a one-second dip put to ... more

Saturday 16th June 2018

How to keep an iron-red glaze from being a bucket-of-jelly

How to keep an iron-red glaze from being a bucket-of-jelly

This is G2890C, a cone 6 iron red glaze. It was so gelled that it was unusable! First I measured specific gravity (with difficulty): 1.48. That's too high, so I added water to reduce it to 1.44. Then I dripped in Darvan 811 (it is recommended for iron-containing slurries). I added it until adding ... more

Tuesday 12th June 2018

Never test bodies or glazes unlabelled with their Insight-live code number

Never test bodies or glazes unlabelled with their Insight-live code number

That is how you know what it is. The recipe. The firing schedule. The notes. The project it was in, information about what came before it and what developed from it. These mugs and that test bar are the same clay, I am doing a preliminary test on a new material from our quarry, it is called "Battle Clay".

Tuesday 12th June 2018

When using stains, customize the percentage, host glaze and firing schedule

When using stains, customize the percentage, host glaze and firing schedule

These are G2926B clear glazes with stains added and fired at cone 6. The one on the left has 11% Mason 6021 encapsulated red. It is pebbling the surface (even with 2% zircon), it may be at the upper end of its firing range. Possible solutions are faster firing up and down to give the stain less ... more

Monday 11th June 2018

Lustreware pitcher by Jonathan Chiswell Jones

Lustreware pitcher by Jonathan Chiswell Jones

The process he has evolved requires 3 firings. First, the dry porcelain ware is spray-decorated with metal oxides (iron, manganese, copper, chrome and cobalt oxides) and then high bisque fired to cone 9 to bond them on and vitrify the body. Then a cover of lead borosilicate glaze is fired on at cone ... more

Monday 11th June 2018

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

Tuesday 29th May 2018

The glaze broke the bottom off the pot!

The glaze broke the bottom off the pot!

A example of a highly fluid cone 6 glaze that has pooled in the bottom of a mug (and crystallized). Glazes normally need to be under some compression to avoid crazing (by having a lower-than-the-body thermal expansion), but if they are thick like this the body does not have the strength to resist ... more

Wednesday 23rd May 2018

Substituting MgO for BaO in a matte will also make a matte, right? Wrong.

Substituting MgO for BaO in a matte will also make a matte, right? Wrong.

Left: G2934 magnesia cone 6 matte (sold by Plainsman Clays). Right (G2934D): The same glaze, but with 0.4 molar of BaO (from Ferro Frit CC-257) substituted for the 0.4 MgO it had. The MgO is the mechanism of the matte effect. Barium also creates mattes, but only if the chemistry of the host glaze ... more

Wednesday 23rd May 2018

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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

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Interactive glaze chemistry calculations.


What people have said about digitalfire

• THANKS so much for all of the information you share at no cost. It really helps me. I feel a little guilty for not subscribing to Insight, but I am working toward that. You have truly changed the way I think about glaze, and I appreciate you. thanks. future subscriber/fledgling potter

• I am impressed with your site - it is very comprehensive.

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

• Thanks, your website is a wealth of information for me and my students.

• Go look at Tony Hansens page and look at Insite. Incredible amounts of information. He has a great explanation of .. Shivering ---and the opposite----- Crazing. Cause and solution.

• When I first opened the program I thought I would never know how to use it and did not open it again until last week. I have been watching some of the tutorials and those made it very easy to understand and work with Insight. Also your website has been very helpful for a project I am currently working on (and in general the understanding of glazes). So thank you for all the information you have collected and made available.

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


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What people have said about Insight-Live

• Thanks! I look forward to seeing your posts. I have read and printed many things you have posted over many years. Have learned a lot from you.

• Just wanted to say thanks for such a great and useful product. Been learning via pen & paper, which I don't regret, but I should've signed up a lot sooner.

• Hey Tony, thanks so much for developing such a useful software. I have come to digital fire for countless questions I have had with clay and glazes.

• 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.

• I spent most of yesterday playing with the “new” (to me) version of insight on line. I love it, it is faster and eventually easier to use. And by the way, thank you for creating and maintaining the enormous data base of ceramic materials and making it available for anyone to use. What a wonderful gift to all of us interested in ceramics.

• I am a big fan of your work. I want to thank you for being there when I have needed and hopefully I will be able to carry on without much input from you. I will be renewing my subsrciption soon and I extol the virtues of the program (and now the Cloud version) to everyone that will listen.

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


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