Tony Hansen's Thousand-Post TimeLine

I am the creator of Digitalfire Insight, Digitalfire.com and Insight-live.com. I have made hundreds of posts like these on my Facebook page and personal timeline. My posts are like no others, they help you understand your glazes and clay bodies, take control. They are also part of the Digitalfire Reference Database (referenced from one or more articles, glossary entries, materials, oxides, test procedures, etc). Visit and Like my page to get a notification each time I post. Search is coming soon.

Pure Alberta Slip at different thicknesses in reduction

A 13 inch vase glazed with 100% Alberta Slip fired at cone 10R. The glaze was sprayed on. It is about 60% calcine and 40% raw powder. When it is very thin, as on the shoulder, it is quite metallic and varies from deep red to brown (depending on thickness). Where thick it is a tenmoku high gloss. The spots on the shoulder are thicker areas that have glossed.

See it in context: GA10-A - Alberta Slip Base Cone 10R

Monday 14th April 2014

What happens when you opacity a colored glaze?

Left: G2934 cone 6 matte glaze with 3% Mason 6300 blue stain. Right: An additional 4% tin added. Notice how an opacified color does not have depth and therefore is lighter in color. Also it does not break to different shades at the edges of contours the way the transparent color does.

See it in context: G2934 - Plainsman Cone 6 Dolomite Matte Base, Opacifier, Opacification

Wednesday 2nd April 2014

Pure grog (brick aggregate) is made by crushing bricks to produce a particulate material that is added to sculpture clay bodies to reduce their drying shrinkage (to reduce drying cracks) and impart texture. Brick manufacturers always have a certain percentage of reject and actually grind the reject bricks and clay together. These are structural high temperature stoneware bricks in a stockpile at Plainsman Clays.

See it in context: Grog

Monday 21st April 2014

Raw red burning clay stockpile

The raw Plainsman M2 clay stockpile before it is ground. This is mined in Montana and imparts red color to various middle and low temperature clay bodies. It is a remarkably consistent material.

See it in context: M2 Red Stoneware

Monday 21st April 2014

Old Blend Feldspar. What is that?

Laguna Clay sells a substitute for the no-longer-available G200 feldspar. G200 HP is higher in K2O and lower in CaO than G200, Minspar is an ideal addition since it's K2O is much lower and CaO much higher. A 7:3 G200HP:Minspar mix produces a chemistry that is remarkably close (on paper) to G200. They label this blend "Old Blend". They also list a product called "New Potash" in their pricelist, that is G200 HP.

See it in context: G-200 Feldspar, G200 HP Feldspar, Minspar 200

Tuesday 17th June 2014

A soda feldspar cone 4-7

Pure soda feldspar (Minspar 200) fired like-a-glaze at cone 4, 5, 6 and 7 on porcelainous stoneware samples. The bottom samples are balls that have melted down at cone 7 and 8. Notice there is no melting at all at cone 4. Also, serious crazing is highlighted on the cone 6 sample (it is also happening at cone 5 and 7).

See it in context: Feldspar

Friday 19th September 2014

Two plasticizers, two results

A comparison of the plasticity of Volclay 325 Bentonite:Silica 25:75 (top) and Hectalite 200:Silica 50:50. Both are mixed with silica powder. The latter (a highly refined bentonite) is much less plastic even though it is double the percentage in the recipe.

See it in context: Hectalite 200, Volclay Bentonite, Bentonite

Tuesday 2nd August 2011

Terra cotta clays are not created equal

A variety of terra cotta clay test bars (and a low temperature porcelain) that have been fired to cone 5. The measurement and weight data from these bars is entered into the appropriate recipes in my account at Insight-live.com; it uses that data to calculate shrinkage and porosities. I will also attach link this picture to each of the recipes. Some are quite vitreous and stoneware-like, some are in the advanced stages of melting, others could take more heat yet.

See it in context: Terra cotta

Friday 19th September 2014

The best dolomite matte base

G2571A cone 10R dolomite matte glaze with added 1% cobalt oxide, 0.2% chrome oxide. The porcelain is Plainsman P700, the inside glaze is a Ravenscrag Slip clear. This recipe can be googled, it has been available for many years and was first formulated by Tony Hansen. This base is very resistant to crazing on most bodies and it does not cutlery mark or stain. It also has very good application properties.

See it in context: Dolomite, G2571A - Cone 10 Silky Magnesia Dolomite Matte

Monday 14th April 2014

Ravenscrag dolomite matte

GR10-J Ravenscrag dolomite matte base glaze at cone 10R on Plainsman H443 iron speckled clay. This recipe was created by starting with the popular G2571 base recipe (googleable) and calculating a mix of materials having the maximum possible Ravenscrag Slip percentage. The resultant glaze has the same excellent surface properties (resistance to staining and cutlery marking) but has even better application and working properties. It is a little more tan in color because of the iron content of Ravenscrag Slip (see ravenscrag.com).

See it in context: Dolomite, GR10-J - Ravenscrag Cone 10R Dolomite Matte, G2571A - Cone 10 Silky Magnesia Dolomite Matte, Dolomite Matte, Matte Glaze

Monday 14th April 2014


These posts are actually pictures referenced on pages in The Digitalfire Reference Database, thousands of pages of explaining things you need to know to formulate, adjust and troubleshoot traditional ceramic bodies and glazes. It is organized as: Oxides, minerals, materials, recipes, articles, glossary, hazards, library, MDTs for INSIGHT, pictures, properties, firing schedules, significant temperatures, tests and troubleshooting. Level 2 desktop INSIGHT and Insight-Live both interact with it.

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