Soda Firing Techniques

[harleyweigle]

Hi Everyone!

 

I recently bought a large old electric kiln for re purposing into a propane fired soda kiln. I have successfully done so (reaching cone 10)  by turning it into a downdraft similar to Simon Leach's online video tutorials. BUT this is where I would love some assistance. I know nothing what so ever about soda firing. 

 

Does anyone have any tips or information on the following:

 

-Soda Recipes For Spraying into Kiln

-Glaze Recipes

-Flashing Slip Recipes

-Wadding

-Soda Firing in General

-Books

-Reduction Cooled Soda?

-Anything.....

 

 

Thank you I am incredibly grateful for any and all responses,

 

Harley Weigle

Shippensburg University Fine Arts Undergrad

[Sputty]

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[bciskepottery]

Soda and salt firing atmospheres are corrosive on soft bricks like those lining your converted electric kiln, unless you have treated the bricks with some type of refractory material. And, once you go soda or salt in your kiln, it is pretty much impossible to go back to just gas firing due to soda/salt collecting on the surface of the bricks.

 

As you indicated you know nothing about soda firing, you would be better off finding someone with a soda or salt kiln and learning the ins/outs of firing with them and understanding soda/salt kiln design. Then build an appropriate soda kiln.

[Marcia Selsor]

Bciskepottery is right.An electric kiln is not built with high alumina bricks to resist the corrosion. You might try spray with a resistant refractory like ITC but you would possibly need a castable resistant to the corrosion in the base where the slag could collect and eat holes through the soft brick. You'd e better off designing and building with a soda resistant castable with high alumina content. Ruthanne's book I believe mentions this. Mine is currently in a different state or I'd check. I built one many years ago. The home made recipe for castable included sawdust which helped lower the cost. Alumina 5% added to the inner layers of the castable while building the layers helps.

 

Marcia

[harleyweigle]

Marcia and B.Pottery,

 

I do understand that there are erosive qualities to soda and salt firing that could potentially ruin the kiln that I had purchased. However, I should have mentioned that I did plan to put an ITC or refractory coating on the kiln. I did look for others in and around my community that salt fire and unfortunately there is just no one within my reach to access. I do have Ruthanne's book and I believe the recipe you are talking about is from Jay Lacouture which is: 1 Part Fireclay, 1 Part Portland Cement, 1/2 Part Sand, 2 Parts Coars Sawdust and 2 Parts Vermiculite.

 

Thank you!

Bciskepottery is right.An electric kiln is not built with high alumina bricks to resist the corrosion. You might try spray with a resistant refractory like ITC but you would possibly need a castable resistant to the corrosion in the base where the slag could collect and eat holes through the soft brick. You'd e better off designing and building with a soda resistant castable with high alumina content. Ruthanne's book I believe mentions this. Mine is currently in a different state or I'd check. I built one many years ago. The home made recipe for castable included sawdust which helped lower the cost. Alumina 5% added to the inner layers of the castable while building the layers helps.

Marcia

 

 

Soda and salt firing atmospheres are corrosive on soft bricks like those lining your converted electric kiln, unless you have treated the bricks with some type of refractory material. And, once you go soda or salt in your kiln, it is pretty much impossible to go back to just gas firing due to soda/salt collecting on the surface of the bricks.

As you indicated you know nothing about soda firing, you would be better off finding someone with a soda or salt kiln and learning the ins/outs of firing with them and understanding soda/salt kiln design. Then build an appropriate soda kiln.

[harleyweigle]

Thank you for the suggestions! I have Ruthanne's book I will most certainly have to look into the others!

 

Thanks again!

As far as books go:

 

'Soda, Clay and Fire' - Gail Nichols

'Soda Glazing' - Ruthanne Tudball

'Salt Glazing' - Phil Rogers

 

...no doubt there are many more.

 

There is an obvious cross-over between soda glazing and salt glazing - techniques are similar, slips are similar, liner glazes are similar - so any good book on salt glazing will be invaluable (hence the Rogers book in the list above), even if you use soda. Plus, you might just figure that your prefer salt to soda, as I did!

[Marcia Selsor]

Yes, that is the recipe I used plus 5% alumina hydrate as recommended by George Roselli from Phila. College of Art in the 1960s. He was our tech person and inventor of those stilts with the wire.

 

Marcia

[Callie Beller Diesel]

Another resource you might want to check out is the Instagram feed of Florian Gadsby (@floriangadsby) who just finished his apprenticeship to Lisa Hammond in the UK. He writes extensively on the soda process in a way that is particularly useful to beginners. Unlike most instagrammers, he writes a full essay with each post.

 

If you're looking for info on reduction cooled soda and wadding recipes, I strongly suggest the previously mentioned Gail Nichols book, but pm me before you try introducing soda into your kiln the way she does: it works a treat, but there's a trick to it if you're using soda ash produced in North America. Gail is from Australia, and the material differences between the two continents matter a great deal in this instance. Pm me your email, and I can send you some recipes of my own as well.

[harleyweigle]

Thank you very much D. Clay! I will certainly have to purchase the Gail Nichols book and I have pm'd you as well. Thank you very much for all of the info. My email should also be in the pm.

Another resource you might want to check out is the Instagram feed of Florian Gadsby (@floriangadsby) who just finished his apprenticeship to Lisa Hammond in the UK. He writes extensively on the soda process in a way that is particularly useful to beginners. Unlike most instagrammers, he writes a full essay with each post.

If you're looking for info on reduction cooled soda and wadding recipes, I strongly suggest the previously mentioned Gail Nichols book, but pm me before you try introducing soda into your kiln the way she does: it works a treat, but there's a trick to it if you're using soda ash produced in North America. Gail is from Australia, and the material differences between the two continents matter a great deal in this instance. Pm me your email, and I can send you some recipes of my own as well.

[Mark C.]

I have some experience with salt kiln that was the thickness of an electric. I converted one to a salt kiln while doing a workshop in Hawaii a few years ago. I sprayed it with ITC-it started in bad shape and lasted 3 fires-I think it would do a few more for sure but the small town freaked out on the fumes and smoke. It also ate the stack in two fires(tin thin walled)

The 1st fire came out incredible. I was on the mainland for the second fire.

You could call me for a few application tips if you want .I'll PM you my number-I'm gone until late Monday to an Arts Festival-well sort of its the Whole Earth Festival in Davis Cal.

I have done lots of coating over then past 25 years.

Mark