Glazes - how it all began

During 2017, I started my own little ceramic business – SolidagoCeramics. Solidago is a plant I distinctively remember from my childhood. It flowers yellow and has a very tall stem, which we used for all sorts. I have fond childhood memories.

During the same time, I became a member of the Barnet Collection, a local group of men and women making in clay. We had regular meetings and selling events, and this is what really got me started in a business sense. I also took part in a selling event at Linda Zeff’s studio in North London.

Nadine taking part in a selling event

3 glaze recipes

At the Barnet Collection, I met a lady called Annegret, a fellow German, and we became good friends. Our last meeting was a Christmas dinner, and we all exchanged Christmas cards. Yet Annegret gave me two cards. I was intrigued, and when I opened them, one was her glaze recipe, including instructions on how to mix, apply and fire. Wow!

Back then, I was mainly working in nerikomi and dabbled in some commercial glazes (more failure than anything else). I loved the simplicity of the coloured clay and only having to think about a transparent glaze. And here I was, the proud owner of a glaze recipe — actually, it wasn’t just one. It was three glazes, and all of them get layered on top of each other.

When it works, it looks great.

A new direction

This really set me off in a direction I never imagined I would go. I still feel like an imposter but… that said, after 7 years, I now have four of my own base glazes with which I can mix up to 40 glazes using oxides and stains. Quite an achievement, I think. 😊

I have learned so much using glazy.org and another software called Digitalfire. This one allows me to calculate the thermal expansion of a glaze, which helps with problems like crazing and crawling.

Having said that, the beginnings weren’t easy and I still haven’t really mastered the layering. I experimented a lot and some pieces turned out fine, others were rather “meh”.

In 2022, after Covid, Calcium Borate frit — a key ingredient for one of the glazes — suddenly became unavailable. I had to rethink the glaze and reformulated it using a different frit. It now works really well as a base glaze at cone 6 and cone 7, and also with other colourants such as stains and copper oxide. It’s just when I layer them all up that it is still unpredictable. Sometimes it comes out ok, and sometimes it crawls or, worse, falls off onto my kiln shelf if I am unlucky.

That got me rethinking the approach, and I started to look for a recipe where there might only be two glazes or even just one. I think the name for these is floating blues. I found a really nice recipe that gave me wonderful deep blues with a hue of green, breaking to brown at the rim. I really liked it, but unfortunately all my pieces “ping” a lot when they come out of the kiln. The pinging goes on for about one week and then stops. I cannot see any cracks or crazes, and in my tests at home, using the pieces, I have not encountered any problems. But it’s not a good sign, and I was determined to find a solution.

More learning

So, this got me into glaze chemistry and learning about thermal expansion and so on. Huh… there is so much to learn. With all of that in mind, I reformulated this new glaze so it has a lower thermal expansion, which solved the pinging problem. But then the glaze also lost the blue and became a dull brown.

Not what I had hoped for.

I am now in the process of experimenting with the fluxes to see if I can get it to melt a bit better, and my current experiment adding a bit of whiting looks very promising on my small test pieces. Let’s hope it is ok on bigger pieces.

At the same time, I am also wondering if my clay might be a little too tight and I might change my clay. There are so many to choose from 😊. I can feel some more tests coming on.

Keeping good notes is essential in ceramics.