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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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Low fire ware cracking during firing. Why?

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

The incredible plasticity that bentonite can impart to a throwing body

The incredible plasticity that bentonite can impart to a throwing body

The vase on the left is thrown from what I thought was a very plastic body, I got it very close to the same thickness from top to bottom (neither of these were trimmed). It has dried to 20 cm high and the thinnest part of the wall is 5mm thick. The one on the right was the same original size but has ... more

Wednesday 17th April 2019

Want bright orange on your ware?

Want bright orange on your ware?

Orange is a very difficult color in ceramics. Inclusion stains are the only reliable method and universally used in industry. But you could ignore that and try a bunch of recipes online, buying exotic materials to complete each one. Maybe one will be orange enough, but will it craze or run or ... more

Wednesday 10th April 2019

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

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?

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?

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

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

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!

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

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