What's Special About Frit 3269 (and some general glaze chemistry chat)

First, I’ll quickly run through some basic glaze concepts. For more detail on these I highly recommend taking a Ceramic Materials Workshop class.

Cone 10 glaze bases have 4 basic components: one or more Alkaline Metal flux, one or more Alkaline Earth flux, Silica, and Alumina. Cone 6 glazes have to bring the melting temperature down, and typically this is with the addition of Boron. The common Boron sources bring at least one Alkaline Earth flux with them. This is important as the AE flux selection is one of the main things that affects how the colourants behave, and typically at cone 6 you automatically have a reasonable amount of Calcium (and sometimes Magnesium) from the Boron source.

So, what makes 3269 special is that it has basically no AE flux. This means you have complete control over the AE flux selection. You might have seen my previous post on Floating Blues, which showed some of the changes that tweaking the AE flux proportions can have on the glaze appearance, but here is the result of using the same glaze proportions with purely Strontium:

Frit 3269 - 30%
Silica - 30%
Strontium Carbonate - 25%
EP Kaolin - 15%
+ Rutile - 4%
+ Bentonite - 2%
+ Manganese Dioxide - 2%
+ Cobalt Carbonate - 1%

The chemistry is basically the same as my usual Floating Blue but the appearance of the glaze is totally different, and this is down to the AE flux change.

There’s no guarantee that changing the AE flux will change the colour, and definitely no guarantee that it will improve a glaze. But having more control over glaze chemistry is never a bad thing. You could use this frit with Calcium and end up with exactly the same chemistry as recipes using other frits, but you have the freedom to change the flux to whatever you want.

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[melodyadams]

I really enjoyed your explanation on the glaze chemistry. You explained it well enough I could understand it. I usually mix up glazes according to the recipe without knowing what and why. Thank you. Love watching your videos. I especially like how you are a calm video person. Unlike some youtubers who have to be so dramatic just to get people to watch their videos.

[avaDesdemona]

I'm not a Potter. I have no clue about glazes. But thanks to your link, down the rabbit hole I go... Amazing information on the glazy site. Thank you!

[jeff]

Thank you for your insightful discussion of the Periodic Table Group 1 Alkali metals, Group 2 Alkaline earth elements, Zinc, and etc.; and their impact on glaze color response.

[jillwazstudio]

Awesome information! I hope you show us what your glaze tests look like! Thank you!

[Chclaid]

Thanks, really interested in getting hold of some frit 3269 now. Glaze chemistry is fascinating.

[erinrcross]

i often get so curious about using things like eggshell as calcium... i keep wondering where you took a class in glaze chemistry. I mix my won but they are very basic recipes like 5 x 20, visually i can change things by swaping parts out but would love to know what is what more for example growing my vocabulary in order to understand better. Nice and helpful. thanks you. love looking at your glazy recipes after seeing them here

[nancyhartshorne]

Most of the glaze tutorial is lost on me right now, but I learn so much from watching you throw repeatedly like that.

[ndPortal]

So what makes floating blue so streaky? From what I get it's phase separation but is it the boron separating from silica or calcium from magnesium? Very interesting talk

[danastripe]

I looked at that Frit but was concerned about the Florine you think this is anything to worry about

[fred_gwatkin]

This was very illuminating, thank you. How did you learn glaze chemistry? Any books or courses in particular?

[maniacmikepepperhead]

Where/how did you learn glaze chemistry?