Javascript must be enabled in the security or content
settings of your browser for this site to work properly

To learn more about cookies search for HTTP cookie at wikipedia.com





Click here for information about DIGITALFIRE Corporation

Tony Hansen's Thousand-Post TimeLine

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

  All | Next 10

High LOI materials can turn your glaze into Aero chocolate!

The smooth surface of this blistering glaze has been ground off to reveal how serious the bubble problem really is. If the body or glaze itself is generating gases of decomposition at the wrong time, and the glaze has too little melt fluidity to pass the bubbles, this can happen. Opacifiers ... more

Thursday 8th August 2019

A runny glaze is blistering on the inside of a large bowl

The glaze is running down on the inside, so it has a high melt fluidity. "High melt fluidity" is another way of saying that it is being over fired to get the visual effect. It is percolating at top temperature (during the temperature-hold period), forming bubbles. There is enough surface tension to ... more

Thursday 8th August 2019

Two batches of EPK tested quite differently in 2018

The kaolin has been mixed 70:30 with nepheline syenite to create a body that matures below cone 6. This enables comparing the degree to which the two kaolins influence vitrification. The darker one is more plastic, has higher drying shrinkage more soluble salts. These dry test bars were fired at ... more

Sunday 4th August 2019

White majolica bases have very, very low melt fluidity

This is Linda Arbuckle's base recipe (66% frit 3124, 23% feldspar, 13 kaolin/bentonite, 9 zircon, 4 tin oxide mixed to 1.62 specific gravity). It is fired at cone 05 creating a super gloss. This is applied very, very thickly (double the thickness of what a stoneware glaze would be). Yet notice how ... more

Wednesday 31st July 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 from a pint jar. 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 ... more

Wednesday 31st July 2019

BEWARE of leaving outsides of functional ware unglazed

This mug is made from the strongest porcelain I have, it is so vitreous that the bare fired surface does not even coffee-stain. So I glazed it only on the inside. That created a time-bomb waiting for hot coffee! Three others did exactly the same. Four other mugs glazed on the outside were fine. Why? ... more

Wednesday 24th July 2019

What is the temperature difference between these two cones?

Four degrees F. I was consistently getting the cone on the left using a custom programmed firing schedule to 2204F. However Orton recommends that the tip of the self supporting cone should be even with the top of the base, not the bottom. So I changed the temperature to 2200F and got the cone on the right.

Wednesday 24th July 2019

Cone 6 Fluid-Melt Transparent Glaze - Jackpot!

In 2015 we did a project comparing common cone 6 fluid-melt base glazes, picked a favourite (Panama Blue) and fixed it's slurry issues and crazing. Fluid-melts almost run off ware when applied thick, but they host stains & opacifiers to produce super-gloss, super-brights. That recipe, G3806C, has ... more

Monday 22nd July 2019

Sourcing Li2O from spodumene instead of lithium carbonate

Lithium carbonate is now incredibly expensive. The glaze on the left employs it. But I was able to source the Li2O from spodumene instead. Spodumene has a complex chemistry, but the oxides that it contains (other than Li2O) are those common to glazes anyway. Using my account at insight-live.com, I ... more

Monday 22nd July 2019

Tin Oxide is expensive, do not waste it by not mixing well

This is a cone 04 glaze on a terra cotta body. Two 300-gram test batches were made. Both have 5% tin oxide added. The one on the left was high-speed propeller-mixed for 10 seconds on a closed container. That was not enough, small agglomerates appear as white specks floating in the glass. The one on ... more

Saturday 20th July 2019

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

Login to your online account

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

• Thank you for all the wonderful work you do for the ceramic community.

• Thank you for this article. I learned more about the science in this one article (What is Deflocculation) than I have in the last 40 years of classes and conversations. Truly enjoyed this.

• Thank you for Digital Fire!!! Your site and your program are wonderful, thank you for the resource!!

• Thank u for your helping researchers .. Thank u for your efforts.

• I normally do not comment on articles I find, but this is amazing. Thank you so much for providing this information! I am a ceramics student in my BFA year, and this is the most comprehensive and helpful information I have found on creating a porcelain casting slip.

• After perusing your site for some time, I am really getting the sense of what a valuable resource it is. Thank you for it.

• I enjoy and appreciate your work very much.


Click here to see all 191

What people have said about Insight-Live

• I have learned alot from you.

• 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.

• 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.

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

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

• And I want to add - you are doing a magnificent job with your webpage. Just unbelievable amount of work and information you put there. I have learned a lot from your webpage. Thank you.

• Your website is like a encyclopedia for ceramics, whatever problem I have I first go to your website and refer to it and learn and understand about it. Thank you so much for your patience and time for helping.


Click here to see all 117

DigitalFire Logo

Privacy Policy