Soda Ice

[Gene Killian]

I understand that the soda ice effect can be encouraged through the use of a high alumina slip applied over a commercial body, or better yet a high alumina body itself, having a soda to alumina ratio around 2.5 to 3.0. I also understand that most if not all commercial bodies have a high silica content to encourage glassing at cone 10. Before trying to go through the laborious process of designing and testing a body mix, if I even dare, I thought I'd inquire of the group whether any have encountered a clay body, or even a slip formula, which has produced the soda ice effect? Hopefully so. Thanx all, for any input on this ...

[Monika Smith]

Ok, what do you mean by soda ice? Sorry, I need to get some of the common terminology in mind. Do you have an image? Like, I go for the jewels... glass green, blues and citrines... ;-) Thanks!

[Gene Killian]

Soda Ice is an effect that occurs when a clay body has a sufficiently high alumina content that the soda doesn't create the usual glassy appearance. The available silica is not enough to form a glassy coating in combination with the soda gases and alumina, so the abundance of the latter, which is highly refractory, takes over and creates a matte white effect, sometimes with small pinholes if silica sand particles are present. The name comes from the icy appearance of the surface. Some claim to see a faint blue cast in it as well. High silica clay bodies don't react the same to the soda gases, and instead tend be be shiny. Much of the information about this was first reported by Gail Nichols (Soda, Clay and Fire), so I am attaching two samples of her work that show this phenomenon.

[Monika Smith]

Thanks! Now I get it. Yes, I've seen Gayle's work. And saw other colours present--pinks and greens if you look really, really close. Her surface is a world.

I also love the water reduction effects and I've seen a lustre effect formed. Even without 'ice' the surface can be incredibly rich. Cheers, Monika

[Cory Lum]

can u send a photograph or post one of 'soda ice' ? i may have had this and can recommend a clay body if i 've seen what u are talking about

[Cory Lum]

oh. !!!! yes !

try using the cone 10 sculpture raku mix. the clay body

[Gene Killian]

Hi Cory. Are you referring to the Sculpture Raku Mix made by Clay Planet? Thanx!

[Cory Lum]

yes sir

[Gene Killian]

I'll try it. Thanx again!

[June Perry]

I'm not sure what you mean by soda ice Gene. Are you referring to the pitted surfaces that Gail Nichols gets on her soda fired pieces?

She uses a high alumina body and introduces water into the kiln, on cooling I believe, to get that effect. Some articles and perhaps, her books contains that information.

June
http://www.shambhalapottery.blogspot.com
http://www.shambhalapottery.com

[Gene Killian]

Hi June. Thanks for your reply. I think in my second message on this string I provided an explanation of the soda ice effect, and provided two photos of samples produced by Gail Nichols. Indeed, the effect is that which she described within her book, also as mentioned above. My primary purpose was not to inquire as to what was the effect, but rather to determine whether anyone had identified a good and reliable slip with a high alumina content, or a commercially available clay body with a similarly appropriate high alumina content, that was known to lend itself to producing the soda ice effect that is described in the Nichols publication. Are you aware of any? Hoping something might turn up. Thanks again for your interest in the matter.

[June Perry - Shambhala Pottery]

Gail she uses a claybody with at least 80% clay content, and an silica/alumina ratio below 3. The other secret is that she does a reduction cooling after she finishes spraying soda, to get that ice effect on her pots.

Here's a theoretical cone 10 recipe I just designed for myself; but haven't yet tried. It should be a good throwing body and should have enough tooth, from the kyanite, spar and fireclays to also make it work for slabs as well. I put some kaolin in to lighten it up for soda/salt firings. It should flash well, as is.

22 EPK
18 Goldart
22 Hawthorne Fireclay
18 Tennessee #9 ball clay
11 Custer spar
9 Kyanite (100 mesh)

*Can add 5% fine to medium grog or sand for more tooth. The kyanite will give it some tooth and you can also use a coarser kyanit for part or all of the kyanite. The kyanite will also help with ovenware.

You can try another version, by subbing Nephy Sy for the Custer. This will lower the silica/alumina to a ratio of 2.5 as well lowering the iron and Titanium a bit.

This has a alumina/silica ratio of 2.58. She has stated that her body has a 3 to 1 ratio; but when you have 80% clay in a body, you risk getting too much silica which can cause too much cristobalite to form in high fired bodies, causing dunting.

If you try this body, please let me know how it works for you. This won't be a white body, but it should flash well. You can also try it or other bodies with her old, high alumina slip recipe. Here's her base recipe.

80 Kaolin
10 Silica
10 Neph Sy

June
http://www.shambhalapottery.blogspot.com
http://www.shambhalapottery.com

[Gene Killian]

Hi June. Thank you for all of that effort!! And what a wonderful starting point. I will experiment with it soon and try to pass on the findings. I'll be out of country for a few weeks, but then will get started. I anticipate, or maybe just hope, that something will be fired in July or so. First step is to pull together the ingredients, and then fix the door light, and then the car's a bit dirty, and dinner, and throw pots, and ...

Thank you again so very much.

Best regards,

Gene