converting an old electric kiln into soda kiln

[Deborah Woods]

I have an old electric kiln I would like to remove the elements from and convert to a gas fired soda kiln. It's 7 cubic feet, top loading. I know I would have to coat the inside and shelves to protect them and know it would not last an extremely long time, but is there any reason I can not do this to try soda firing on a beginning level? If you agree or disagree, why? Thanks for any input, I would really like to try soda.

[Kyle Carpenter]

i did this in college. worked for about 10 firings. it's what got me hooked on salt firing. could last longer if you coat the brick well with zirconium or some commercial mixture.

[Pamela Theis]

This is not a top loader, but may help with your research.
http://www.potteryinaustralia.com/Mar05/sk_tech.html

Also, I think someone at Towson University did this, but I am not sure. Ask Matt Hyleck (he's on ning) if he knows anything about it or someone to contact at Towson university.

Also note it may be a good idea to consider going up to cone 6 rather than 10. It is my understanding that the top loaders will be greatly uneven, but as I have never done this I cannot say for sure.

I also thought that at some point there was an article in CM or some other magazine about doing this. I would google it.

Good Luck,
Pamela

[Pamela Theis]

Here's another site to check out: http://voofavoofa.blogspot.com/2007/08/081807-kiln-conversion.html

this one is for a top loader.
Pamela

[Deborah Woods]

Thanks for the input so far. Very encouraging. I'm going to give it a shot. I plan on using my current clay, Standard 365. It's a Grolleg Porcelain. Not sure yet if this is suitable, but with slips maybe. I just ordered Gail Nichols book on soda firing, so should learn a lot from that. When I begin the conversion I'll document it and post on my blog if anyone is curious.

[Pamela Theis]

Isn't 365 cone 6? If so, I posted some glaze/slip recipes for cone 6 in a different discussion that would help you get started.
Pamela

[Deborah Woods]

Pamela, 365 is a cone 6. The only slip recipe I could find that you posted was the one from Julia Galloway, Flashing slip. I assume that's the one you mean. Thanks and I will put it in my notebook. A little update on my kiln. It's been sitting outside for a couple of years now, under plastic which has weathered and eaten away. I opened it up yesterday and it has taken a beating from the weather. It must have absorbed gallons of water. So we moved it into the shed, which I should have done long ago, so it can begin drying out. I feel awful having neglected it so much. I think I will candle it empty for a long while before I fire to be sure it is dry.

[Faye Menis]

Hi Deborah, I did this in my days at Vermont Clay Studio, and it was an excellent teaching tool for demonstrating different atmospheres, and how to adjust a burner/damper to get them. You can have a very quick turn around as well as the opportunity to experiment without putting a huge amount of work at risk. I coated the walls with kiln wash which worked well, probably fired 10-15 times wthout even being close to killing it. One of the keys I found to getting it hot fast, cone 9 in less than 3 hours, was the addition of about a 4 foot stack on top of a round hole in the lid(updrafting). Just a piece of 4 or 5 inch metal pipe. I then used a soft brick as a damper on top of that. Give it it go, lots of fun! Jim Dugan

[Deborah Woods]

I was wondering about maybe creating a tall stack, as opposed to just damping directly over the hole in the lid. I will give your idea a try. Thanks-Deb

Here's another question while I am thinking about it. I need to find out from my gas company if I can somehow pipe directly off our LP tank we already use. If I can't and need to get a separate tank, I wonder how many gallons it should be to comfortably reach cone 6 for one firing. I know some may say to get a really big tank so I can use it in the future for a larger kiln, but my house is on the market and I'd like to be able to move it where I move. When I am ready to build a legit soda kiln, maybe 30 cu ft, I will get an appropriate size tank for that kiln then.

[David L Hayashida]

For coating soft brick we used kiln koat by smith sharpe very expensive...some kind of zirconium coating. Apply the mix very thin and wet the brick before applying...perhaps something to do before drying out your kiln? The mixture will peel off if applied too thick or if put on just plain dry brick. I seem to recall someone mentioning a dry shino glaze but maybe that was for hard brick? You could have a test soft brick you load into each soda firing, coated with various (coded/identifiable) products on it to see how various coatings fair in the soda kiln. Others say ITC but i've not used that product. We had a kiln that was not in the rain but in an unheated space and that kiln smoked (off water) for quite a long time before reaching temp...would have been good for a initial shino firing. Regular kiln furniture will not hold up very long...silicon carbide shelving (expensive) is the only way to go. Be sure to have a proper vapour mask. Someone mentioned cone 9 in 3 hours...maybe it's just me but that sounds like very unusual advice?
best
david hayashida -king's point pottery- newfoundland-canada

[Deborah Woods]

David, thanks for all the info. I too have heard about coating the inside with a shino glaze. I was planning on using ITC or a homemade version I have seen recipes for. I've read to put it on thin and it's good that people tell me, because I can see myself just slathering it on thinking, if a little is good than more can only be better! There is a kiln plan somewhere I have seen for a fast-fire kiln. It's a small kiln I think, but it supposedly can go to cone 10 in like 2 1/2 to 3 hours. I have no desire to fire that fast, but I guess in theory it can be done. I plan on using the furniture I have for the kiln. I believe it is plain corderite (spell?) It doesn't fit my other kilns so I don't mind it's giving it's life for a more noble cause. But when you say it won't hold up, do you mean just get all funky, or like cracking apart in the middle of the firing. I don't expect the whole kiln to last too long really, so as long as the furniture holds up as long, I am happy.

[David L Hayashida]

The furniture may last 4-5 firings has been my experience...they start to crack as they get eaten away. I guess I'll have to look into this fast firing business...new(s) to me.
best
david hayashida

[Deborah Woods]

There are a couple of pages that discuss it in Susan Peterson's book, "The Craft and Art of Clay". Pages 223-224. You can probably find some info on the internet if you google her name and fast-fire kiln.