Doesn’t high speed mixing create bubbles in the glaze?

What if mixing creates bubbles in our glaze?

Question: When high speed mixing, is it necessary to allow the glaze to sit for some period of time before dipping to avoid tiny bubbles? What to do about those tiny bubbles?!

A couple people were asking about a milk frother, if that’s an appropriate glaze mixer. I’ve never used a milk frother, for making lattes or mixing glazes or anything, so I can’t really say. It does seem that the point of a milk frother is to create bubbles. Is that bad for a glaze? I don’t know for sure.

What I do know is that I have personally laboured over removing bubbles after the glazing process. I’ve had all these bubbles that are popping on the surface of the glaze, and I’ve spent so much time with my finger, rubbing out these bubbles, trying to make them smooth.

And then one day, I was like, “Hmm, I wonder if all of this bubble rubbing effort is really doing anything…” So I just left all of the popped bubbles on the surface of the glaze. And what I learned was, if your glaze is properly melted, it should all smooth over.

I’m sure there’s a case where excessive bubbling could lead to some pinholes or blistering, but I think that once the glaze is in a melted state, all of those bubbles kind of disappear and pop as the glaze is liquefying on your pots during the firing.

Here’s what I did and what you could try: I had this glaze that was really bubbly after high-speed mixing. I dipped some test tiles and I took pictures of them before the firing, and I left the bubbles there. Then I took pictures after the firing and compared them. 

There was no evidence of the bubbles after the firing. So then I just stopped rubbing all the bubbles. It was an unnecessary step.

I know that at the Rec Centre where I used to work as a technician, our shino glaze would bubble a lot after mixing. I think it might have to do with soluble materials in the glaze that were causing the bubbling. Our shino glaze has a lot of soda ash in it, which we dissolve in hot water before adding it to the glaze bucket. And when we would high-speed mix the shino glaze in particular, we got a lot of bubbling. But those bubbles never showed up after the firing. It all just melts and blends together.

Can we just shake up store bought pints of commercial glaze?

Question: Regarding mixing and stirring for store bought pints, is shaking the bottle bad to mix it?

I have never worked with store bought pints of glaze but I can’t see why shaking it would be bad. It seems like that would do the job. I can see why you would want to. It might be hard to get an immersion blender in there. And that might be why people were asking about the milk frothers, because they are like a teeny, tiny little spinny thing that would fit into a small, narrow mouth jar.

I don’t see any problem with shaking the bottle, but I’ve never tried it. So take that as you will. I just don’t have experience with that.

Should it be stirred instead? I think shaking it should be fine, but all I can say is test. Test shaking it. See if it becomes super bubbly and whether the bubbles bother you.

I think that for store bought pints that are meant for brushing, they usually contain CMC gum or some sort of binder that helps them to stay mixed. And I think stirring them should be just fine for brushing. I think it’s dipping glazes that are more likely to settle out where the water rises to the top. But again, I just don’t have experience with those types of glazes.

So I’m going to say, I would try shaking it. Because that sounds really easy to do. Give it a good shake and see. Just do a test and if it seems fine, then it should be fine.

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!

What You Need to Start Mixing Glazes from Scratch

Are you interested in learning how to mix your own glazes? When you start mixing your own glazes from scratch, your glaze options become infinite. Not only will you be able to stand out with unique glazes that you created yourself,  but you'll also start to develop a more intimate relationship with the materials you are using to make your pots.

But before you take the plunge into the world of glaze mixing, you might be wondering what tools and supplies you’ll need to have in your studio. Watch my free "on-demand" class to find out! Click the button for all the details.

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.

Register now.