Brushing glazes can go on unevenly for more than one reason
Both of these were glazed by brushing. The inside transparent and white glazes are fairly easy to apply evenly but the bright color on the outside left one certainly is not. The problem is a combination of things. It is difficult to apply it evenly with a brush. It is difficult to get it on thick enough. And this commercial glaze does not contain enough of the purple stain (so I added 6 grams of Mason 6304 Violet powder to the 2/3 of a jar I had left). That, more careful brushing, and an extra layer produced the piece on the right!
Context: Brushing Glazes
Wednesday 24th April 2019
How to give children a good experience in working with clay
Teachers who have never worked with clay face a formidable challenge with this. This read-in-three-minutes page is a complete beginners crash course in what you need to know. It explains what clay is, the advantages of working at lower temperatures, how to plan and inspire the children before starting, how to join and dry pieces, what is glaze and how to use it and how to fire the ware. The page explains things with an objective that the reader understand the basic whats, hows and whys of ceramics and pottery.
Context: Teaching kids to make things from clay
Tuesday 23rd April 2019
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 blister
or leach or cutlery mark or crawl
? Or you could put an orange stain into a transparent glaze you already know works on your clay. Or, how about trying a premixed orange at low fire? Ware can be amazingly functional
and there are so many other bright colours available.
Context: Encapsulated Stains
Wednesday 10th April 2019
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 sealed and left it for several days. Even after that it did not detach easily, even though the bat had been dry. The base was still quite soft but the rim was stiff enough to enable turning it over and trimming it (I endeavoured to create a cross section of even thickness). Then I dried it under layers of cloth for several more days. It took at least a week. Had I allowed the rim to dry out during the first few hours it would likely have cracked later on.
Context: The Black Art of Drying Ceramics Without Cracks, Drying Performance, Body Cracking During Drying
Tuesday 9th April 2019
Supercharge the plasticity of cone 6 reclaimed clay
If your reclaim is short and non-plastic you can make it better-than-new by using an additive of 50% ball clay and 50% bentonite. While only a few percent bentonite supercharges the plasticity
of any clay body it is almost impossible to get it to mix into a wet slurry or plastic clay. But thoroughly shaking it together with ball clay (in a plastic bag) separates the super-tiny particles of bentonite between the almost-as-tiny particles of ball clay, that new powder will easily mix with water. And it fires to a tan-buff stoneware at cone 6 so it won't change the fired appearance of most buff or brown cone 6 stoneware bodies.
Tuesday 9th April 2019
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 produces an ultra-gloss surface of high quality on mugs 2 and 3 (Frit
3249 and 3195). On the outside we see it this glaze on the white slip until midway down, then on the bare red clay. The amber glaze on the first mug (with Frit 3124) has a pebbly surface. These are fired using a drop-and-soak
firing schedule. Some caution is required with the 3249 version, it has low thermal expansion
(that is good on bodies that normally craze
glazes, but risks shivering
on ones that do not).
Context: Ferro Frit 3249, GA6-A - Alberta Slip Cone 6 Amber Base Glaze, GA6A Alberta Slip base using Frit 3249 and 3195 on buff body, P300 and M370 mugs with GA6A Alberta Slip (using Frit 3249), Alberta Slip Cone 6 Base with Frit 3249, 3195, Plainsman Cone 6 Slow Cool (Reactive glazes)
Monday 8th April 2019
Functional ware at low fire! Don't dismiss it just yet.
These were only fired at cone 04, but they are durable enough to last some time with normal use. The insides have a transparent glaze (Spectrum 700), it is leadless and completely safe. These are great insulators, they keep coffee warm longer than porcelain or stoneware. The feet are glazed so they are fine for the dish washer. They are super-light, the body is made from ball clay and talc and throws really well. These shrink very little on drying (in this case less than 2% compared to porcelains which can be 8% or more). These are inexpensive to fire, only four hours to cone 04. They withstand impacts better than you think (a thin porcelain mug propagates cracks and can shatter). Colour, glorious color! These are Spectrum Opaque low fire glazes, dozens of wild colors are available.
Context: Which is better for functional ware? Cone 04? Cone 10 reduction?
Monday 18th March 2019