The only way to learn about which ceramic glazes work for you is to test them. The idea is to study what happens when you mix various amounts of various ingredients in a glaze and fire them to various temperatures. It’s about understanding how different materials affect each other in order to be able to achieve the results you want, and to troubleshoot when the results are really not what you want.
Sounds confusing? Well yes, and certainly not great for those of us who avoided chemistry at school because, in essence, this is known as ‘glaze chemistry’ which is complex and at times intimidating.
Recently, I was working on blending some new colours into my wares, not just new colours but new applications – white with a yellow stripe, white with a purple stripe and several others. I bought some new commercial stains and glazes in the colours I want, and experimented with them. I tried several glazing tests and methods:
- A) Mixing commercial stains into engobes, as I do with colouring oxides.
- B) Mixing stains into my own glazes.
- C) Using coloured commercial brush-on glazes over my own glazes.
- D) Using low-temperature glazes over a high-temperature matt glaze in the hope that they would run down and blend into the base glaze.
So far, I’ve had very limited success with these tests. In general reds do show up, yellows disappear or come out faded at best; and the colours stay put, they do not run down the sides of my pots
I’d like this tale to have a happy ending, but I’ve not yet solved this chemical conundrum. However, I must emphasize that it’s vital to keep all test results. Even if they are not what you’re looking for at the time, this little bit of research may lead you to what you are looking for later on.
Also, my quest for a solution to my glazing problems led me to a website which aims to make glazing chemistry more like glazing cookery, with all recipes tried , tested and available at the click of a button. Who knows – I might be uploading a recipe of mine to this collection quite soon?! http://ceramicrecipes.org