When you don’t have all the materials in a glaze recipe

When you start looking for glaze recipes and have a limited number of materials on hand, you may find that you have almost (but not quite) all the materials for a million glaze recipes, but you can’t find a recipe that only uses the materials you currently have.

In 2016, I wrote a blog post called Start Mixing Your Own Glazes – A Shopping List where I offer a list of glaze materials that I would buy if I was just getting started and on a budget or had limited space.

It was one of the very first blog posts I ever wrote, before I had a Facebook group and an email list, when no one was really paying any attention to my website. I hadn’t considered that someday, people might actually read it and go out and buy all these materials.

Now that I’ve heard from several people who have done just that, I realize that more info is required for it to be super useful to a beginner.

What glazes can be made with this list of materials?

Why did I choose the materials that I did?

Most glazes can be re-formulated with different materials

When I created that list, it came from a place of knowing how to easily substitute glaze materials for each other. I knew that a lot of recipes out there could be re-formulated to be made using the ingredients on the shopping list.

For example, I knew that if a recipe called for Wollastonite, which isn’t on the list, I’d be able to substitute Whiting and Silica, which are on the list.

The thing about glazes is that the recipe and material choice is less important than the chemistry of all the materials combined. You can recreate a glaze using different materials, as long as the chemistry matches.

So in creating this glaze material shopping list, it seemed very versatile to me, but I hadn’t considered that many of the people who would buy this list of materials might not know how to re-formulate glazes using material substitutions.

So, to make this shopping list more useful to everyone, I decided that I would figure out which of my glaze recipes could be made using only these materials.

It turns out that only my Black Velvet glaze and my Calcium Matte glaze matched the shopping list, as they were written. And even so, Black Velvet contains Cobalt and Calcined EPK, which aren’t on the list. Luckily, Calcined EPK can be created using regular EPK. Follow this link to learn how to do that.

Then I looked at the rest of my recipes and realized that many of the base recipes could be re-formulated using this list of materials. A base recipe is just the recipe without colourants added.

So I went ahead and re-formulated all the recipes I could and ended up with 9 different base recipes that can be made using the materials on the shopping list. I created a bookmarked collection of these base glazes called “Starter Materials – Glazes” on glazy.org.

Here’s an example of my clear glaze recipe before and after re-formulating with different materials. The chemistry (UMF – Unity Molecular Formula) is inside the turquoise rectangle. You want to get those numbers as close to matching as you can.

Adding Colourants and Opacifiers

You can take any of these 9 base recipes and add colourants to them to get a wide variety of coloured glazes, depending on which colourants you have.

On the shopping list, the only colourants I included were Copper Carbonate and Red Iron Oxide, in order to keep costs down. Copper generally makes greens and blues and iron makes yellows and browns.

Another very common colourant you may want to have on hand is Cobalt which makes blues and purples. Copper, Iron and Cobalt are the 3 most common glaze colourants. Other less common colourants include Manganese, Nickel and Chrome.

You may also want to have some opacifiers on hand to further increase your colour options. Zircopax is the cheapest opacifier that doesn’t have a big impact on the chemistry of a glaze. 5-10% Zircopax will turn a clear glossy glaze into a white glossy glaze.

Titanium dioxide and Rutile (which is titanium plus iron) are also opacifiers but they play more of a role in the chemistry, causing things like micro-crystallization and variegated colours.

Tin oxide is the most expensive and least common opacifier and is often used with Chrome to make pink.

I recommend having at least one opacifier if you really want to experiment and have the most diverse options.

You can test base recipes with different percentages of colourants, you can mix and match different colourants, and you can combine colourants with opacifiers. There are an infinite number of possibilities when you start playing around with different percentages of all of these glaze additives.

Here are the most common percentages I see for each of the colourants and opacifiers:

• Copper Carbonate 1-4%
• Cobalt Carbonate 0.5-2%
• Red Iron Oxide 1-10%
• Manganese Dioxide 1-5%
• Chrome Oxide 0.1-2%
• Nickel Oxide 0.5-2%
• Zircopax 5-10%
• Rutile 1-6%
• Titanium dioxide 1-4%
• Tin oxide 1-2%

When adding colourants and opacifiers to a base recipe, you just take the glaze batch size and multiply it by the percentage of colourant to get the grams of colourant.

For example, if you want to add 2% colourant to a 1000g batch of glaze:

1000g x 0.02 = 20g of colourant added to the base recipe.

So now we have a list of base glazes that can be made with the limited materials on my shopping list, just by taking existing recipes and substituting materials we don’t have for ones we do have. And then we can add colourants as desired you can choose the colourants shown in my original recipes or try completely new ones!

If you test any of them, it would be great if you could upload your photos to these recipes on glazy.org.

Live Glazy Demo

Want to see how I did the material substitutions to re-formulate these base recipes?

Tune in to Ceramic Story-Time (video posted at top of blog post) where I go live on video, read this blog post out loud, and then take you into glazy.org to show you where to find these base glazes and demonstrate how I did the material substitutions.

And if you love Glazy, please consider supporting its development with a donation. For just $2/month, you can unlock some great features including a magic button that makes material substitutions for you. All you do is tell it which materials you have and it will match the chemistry of any recipe with a click. I have no affiliation with Glazy, I just really love it.

Learn How to Mix and Test Glazes

If you’ve never mixed a glaze from scratch before and want to learn, I teach an online workshop called Glaze Mixing Essentials where I show you all the steps to mix a glaze and then test a base glaze with multiple colourants. Click the link for all the details.

Join my free community

If you love learning about and discussing glazes, I'd like to invite you to my free social learning Facebook group called Understanding Glazes with Sue. The group is full of videos and discussions about firing, mixing glazes and fixing various glaze issues. Please join!

5 Ways You Can Make Your Glazes More Amazing (using glaze chemistry)

If you’ve ever wished your glaze could be just a little more…

• cost effective
• green/red/blue/purple
• compatible with your other glazes
• matte/glossy
• stable/fluid

… then you don’t want to miss this free class!

Date: Sep 21, 2023

Time: 10:00am Pacific / 1:00pm Eastern / 6:00pm UK time.

A replay will be available to watch for a limited time if you can't make it live.

The Art of Glaze Chemistry

Learn how glazes are formulated by using the UMF (unity molecular formula) and glaze calculation software to:

• create different glaze surfaces like matte, satin or glossy
• get glazes to melt at different temperatures or ensure your glaze is being fired to the right temp
• create durable, functional glazes
• fine tune the colours of your glazes
• fix crazing and other thermal expansion issues

This is a deep dive into all the chemistry that's happening inside the kiln.

Registration open Sep 21-29, 2023.

Learn to Mix Glazes from Scratch

If you’ve never mixed a glaze from scratch before and want to learn, I teach an online workshop called Glaze Mixing Essentials where I show you all the steps to mix a glaze and then test a base glaze with multiple colourants. Click the link for all the details.

September sale: Save $30 if you register by Sep 30, 2023.