Armchair Potting

Some time ago a lady told me “Mike, all the time you talk about yourself.”
I thought about it for a while and realised she was right with a very slight exception. I do not know much about anything but ceramics, and so I talk of my experiences which took place during the last 50 years.

In a way I am a very lucky bloke.
My biggest opportunity came when I got the position of a chemist at H.L. Brisbane and Wunderlich in 1959. My boss, the chief chemist Alec Johnson, kept me busy for a while with a number of projects in many different ceramic fields i.e. porcelain insulators, acid resistant bricks, English earthenware and fritted glazes, sanitary ware and high fire glazes, bone china flowers for graves, terracotta glazed tiles for cladding commercial buildings, heavy clay industrial products bricks, roofing tiles, salt glazed floor tiles, sun screen blocks, fireplace decorative bricks etc

He gave me approximately 3 months to finish each individual job; and remember, at the same time I also kept my eyes on quality control in the Subiaco Factory. And I loved it very much, finishing each project within 4-6 weeks. One day when I gave him the results of a 3 months project in 4 weeks, he jumped up from his chair and screamed at me “get lost and find your own projects”.

Our laboratory was very well furnished with the most modern instruments you find only in research institutions. And now, I had quite a lot of time to do what ever I wanted, without hiding things from my boss. My mate, Terry Butterfield working with me, used to warn me –be careful the boss will sack you. I thought to myself   “why, after all I have everything under control”.

During those times I developed a number of my own projects and one of them I’d like to describe now.
(I presented this project at Ceramic Conference in Sydney 1981) :
Low fire raw glazes developed by the help of eutectic compositions containing Lithia bearing minerals.
Orton cone 04- 5.

Briefly, in this exercise, three eutectic compositions were mixed together on triaxial basis and fired to OrtonCone 04,02 and 5 under oxidation.

Mix A is eutectic composition of lithia, spodumene and silica with MP 930°C.

Mix B is eutectic composition of calcia, alumina and silica with MP 1170°C.

Mix C is eutectic composition of calcia, zinc ox, alumina and silica with MP 1030°C.

The most promising blend of the following composition;
Spodumene 26.3%
Whiting       26.1%
Zinc oxide     8.0%                                                                                             
Clay             10.0%
Silica            29.6%
 Total           100.0%

The named base glaze was used to develop coloured glazes with the help of metallic oxides in additions
[%]as we use in any other glaze. The base glaze fired to OC 04 was white matt;                                     
OC 02 was white glossy                                      
OC 5   was semi- white glossy

And so, my friends give it a go. You can have earthenware glazes without frits; all the glazes should fit to earthenware and mid fire bodies.

Cheerio for now Mike