Iron Reactive Transparent Glaze

[Tamas]

Hello Everyone,

 

 

I was looking at this commercial glaze: https://www.scarva.com/en/Scarva-GZ2214-Iron-Reactive-Glaze/m-5060.aspx

 

and was wondering if you could tell me which component/property of this glaze made it 'iron reactive'? I would love to locate a glaze recipe with the same effect that I could try, or develop a glaze on my own.

 

Thanks!

 

 

[Callie Beller Diesel]

Your link is going to the Scarva home page, and has a bunch of tools on it. Which glaze?

[Tamas]

That is strange, when I click on it it takes me straight to the specific page. Apologies.

Anyway, the glaze is the Scarva GZ2214 Iron Reactive stoneware glaze.

 

[Joseph Fireborn]

 

The website is bonkers, but I did a little googling and found this image. I assume it is the one your talking about?

[Tyler Miller]

Joseph,

 

that website is indeed bonkers. It seema they want you to navigate through their store front whether you need to or not.

 

Tamas,

 

that look can be achieved a number of ways by a studio potter. Jonathan Walburg wedges iron-bearing lake superior sand into his porcelain to achieve a similar, but more speckled effect under his maple ash glaze base. But that precise variegated look is likely due to a strong flux (lithium?) to pull out the iron and some rutile--which likes to variegate.

[Tamas]

Thank you, guys - indeed that was the glaze I was referring to. Yes, I know I can get a speckled look in various ways, I was just curious what wizardry they used to achieve it in the glaze.

 

Here's what Scarva says about the glaze:

 

 

GZ2214 is a cone 9 stoneware glaze developed to react with iron in the clay body.  Bodies with a higher iron content will react more readily with the glaze, creating a beautiful reddish brown effect highlighting iron speckles. Bodies with lower iron content will yield a whiter glaze with fewer flecks.

• Firing range: 1200-1280°C
• Finish: Glossy
• Leadless

The image shown is of SP90 Burren and of SW10 V9A showing how the glaze reacts with different amounts of Iron in the clay bodies.

[Tyler Miller]

Tamas,

 

I think it's lithium, which has a tendency to play with the body-glaze interface and has the best chance of pulling up iron.

[Chilly]

The link worked perfectly for me, perhaps it is UK biased?

[dhPotter]

Tamas,

 

This glaze looks like a Nutmeg. Bill Van Gilder has a nutmeg recipe.

 

Tyler, his recipe has Spodumene 23.3%

[Sputty]

.

[neilestrick]

Looks like a typical 'nutmeg' or 'oatmeal' reduction glaze. They typically have lithium (spodumene) in them.

[neilestrick]

Here's one I used to use:

 

Custer            28.30

Spodumene   18.87

EPK                24.53

Dolomite        20.75

Whiting            1.89

Tin Oxide         5.66

Cone 10 Reduction

[Marcia Selsor]

The link worked for me too. As Neil points out with his reduction glaze, iron is reactive in a reduction firing. The reduced oxygen in the atmosphere pulls oxygen in iron oxide bringing the iron to the surface of the glaze...at least visibly. If the glaze in the photo is fired in an oxidized atmosphere, then they  have developed a nice commercial glaze for oxidation.

 

Marcia

[Tamas]

The link worked for me too. As Neil points out with his reduction glaze, iron is reactive in a reduction firing. The reduced oxygen in the atmosphere pulls oxygen in iron oxide bringing the iron to the surface of the glaze...at least visibly. If the glaze in the photo is fired in an oxidized atmosphere, then they  have developed a nice commercial glaze for oxidation.

 

Marcia

 

That makes sense, thank you, Marcia. I fire electric, so this particular solution is not an option for me then.

[Babs]

What cone are you firing to?

[neilestrick]

With enough iron in the clay, and a good glaze, you can get a very similar effect in oxidation. It just takes more iron in the clay to get the effect. I've got some cone 6 oxidation glazes that I modified from cone 10 reduction, and on a speckled brown cone 6 clay they are nearly identical.

[Tamas]

What cone are you firing to?

Babs - I fire to cone 6-7.

[Tamas]

With enough iron in the clay, and a good glaze, you can get a very similar effect in oxidation. It just takes more iron in the clay to get the effect. I've got some cone 6 oxidation glazes that I modified from cone 10 reduction, and on a speckled brown cone 6 clay they are nearly identical.

 

Neil, that is interesting. I will look for and try out some clays to see if I can get close.

[preeta]

Neil do you mix your claybody for the right iron or do you go with a commercial body?

 

Could you use iron engobe or slip or even an iron wash over non iron clay to get similar response?

[neilestrick]

I use Standard 112 speckled brown. Great stuff. Yes, an iron wash could give you a nice effect.

[Min]

If you are looking for that rusty red with cream look for cone 6 oxidation look for recipes containing both tin and iron. There are a quite a number of them on this link.