Glaze making // my choices explained
Making glaze for ceramics is not an easy job; it’s massively time-consuming, and you really need to think like a scientist to understand what you are doing. However, if you don’t make your own glazes from scratch, you will never know exactly what’s in them. Commercial glazes can be beautiful, food-safe and easy to use, but you can’t access the recipes or find out what the raw ingredients are. Sadly, that means you have no clear idea—firstly, what you might be absorbing through your skin, and secondly, where those raw ingredients have come from.
I chose to make my own glazes so I can fully understand what I’m working with, consider how my choices affect the planet, and offer clear transparency to anyone who buys my pottery.
Through years of research and asking questions as a continuous part of my work, I have learned a great deal about mining, raw ingredients and what’s best to avoid when trying to make sustainable choices. I begin by creating what is called a base recipe, which typically consists of three to ten raw ingredients that I carefully weigh out, add water to, sieve, and then repeat until the mixture is smooth and cream-like. Every batch needs testing and then re‑testing to ensure it reaches the right consistency to achieve the desired finish, but that’s not even the most complicated part. These base recipes draw on different raw materials that are mined across the globe to varying standards and are intended for use across a range of products. The environmental and human impacts of mining in particular countries are deeply concerning for many reasons: toxic pollution, corruption, child labour, serious injury and death among workers, acidic water contamination, coastal dredging and much more. Without a doubt, these issues are cause for serious worry. Predominantly, reports of these destructive practices come from countries such as Brazil, Canada, China, Australia, India and the Democratic Republic of Congo.
Children sorting cobalt ore in Kolwezi in the Democratic Republic of Congo © Amnesty International
There are so many reports out there to read about the dark side of mining and its really scary to think about. One particularly distressing aspect is the abuse of children in copper and cobalt artisanal mines in the southern Democratic Republic of Congo.
These children fall ill with various infections from working in polluted water or being exposed to mercury or uranium. Artisanal mining consists of digging, washing and sorting minerals all by hand. A shocking 40% of artisanal mining workers in the Democratic Republic of Congo are reported to be children as young as 3.
According to Tanya Talaga the Indigenous Issues Columnist, a Christian relief organisation called World Vision, interviewed 50 children working the mines. 19% told World Vision they had seen a child die while working, 87% felt severe body pain, 67% had a persistent cough and many of the girls had genital infections due to standing in waist-deep toxic water to work.
Mining minors: The pain of African child workers
So how do potters avoid this? Well, many don’t even know about it and simply buy ingredients from their local supplier without giving it a second thought. It is not information that is readily available: supply chains are often opaque, details are not disclosed, and the topic is rarely discussed. There are clear international guidelines for responsible sourcing; however, like many others in today’s world, some companies do not operate within them and end up compromising human rights and the environment for the sake of profit. Yes, it is their responsibility to deliver clean and fair raw materials, but I also believe that as an individual maker, I must take responsibility for what goes into my pottery. Understanding where my materials come from and asking questions about the supply chain as a consumer is something I value and build into my practice. To make a consciously more sustainable glaze, I have developed recipes using my most local ingredients and purposefully avoid materials I do not trust. It is both the carbon footprint and the ethical standards of mining that dictate my choices. I predominantly use British-mined ingredients to make my signature glaze recipes — a shiny, clear and chalky white. I contact each provider to confirm how they are produced, what is in them and where they are sourced from. It can be really hard to identify what to avoid, so I thought it would be helpful to end this post by listing a few of my favourite ingredients and where they are mined, followed by a couple of things I avoid and why.
Some glaze ingredients I love:
Hyplas Ball Clay - mined in Devon
Grolleg China Clay - mined in Cornwall
Dolomite - mined in Derbyshire
Whiting - mined in Derbyshire
Soda Feldspar- Norwegian sourced
Some glaze ingredients I avoid:
TALC — The illegal mining of talc in Afghanistan is funding insurgent activity by groups such as the Islamic State and the Taliban, with around 80% of that supply reportedly ending up in the USA and Europe.
SODA ASH — Often produced via an environmentally harmful industrial method known as the Solvay process, which consumes large amounts of energy and generates polluting by-products.
BONE ASH — Made from the bones of farmed cattle. This raises animal welfare concerns and contributes indirectly to the substantial CO2 emissions from livestock farming, an environmental problem I do not want to support through my work.
COBALT — The Democratic Republic of Congo currently produces more than 80% of the world’s cobalt; the industry there is plagued by human rights abuses, including child labour. I can’t always avoid cobalt in devices like mobile phones, but I see no need for it in my pottery. Where we can avoid causing harm, I believe we should choose the kinder option. x
