[Clayart] Oh, this is kinda sad. Rox in oregon

[vincepitelka at gmail.com]

Hi Roxanne - 
Bailey makes a soda kiln, and I expect that Geil would too, but it would be very expensive, even for a small one.  

Our dear Mel gave some inaccurate information.  Salt kilns are the ones that cause everything around to rust, because part of the effluent from salt kilns is hydrogen chloride gas, which condenses on metal surfaces as dilute hydrochloric acid (same thing as muriatic acid).  I believe that soda kiln exhaust creates a dilute carbonic acid that will also cause things around to rust, but not nearly as bad as a salt kiln.  The fumes that come out of salt and soda kilns are not toxic.  Wil Shynkaruk at Moorhead State University in Minnesota and Jeff Zamek in Massachusetts have both done the definitive research on this, and there is no reason at all to be paranoid about toxicity with salt or soda.  

A salt or soda kiln will last longer if made out of hardbrick, but you do not have to make them out of hardbrick if you're not going to be doing production.  At this point, I am sorry I didn't build mine out of softbrick, because I only fire four to six times a year, and a soft brick hotface with a good resistant spray-on liner would last decades and my fuel consumption would be a lot lower.  Years ago Wil Shynkaruk and also Ruggles and Rankin recommended a spray-on zirconia (zirconium oxide) (do not use Zircopax, which is zircon - zirconium silicate) coating for softbrick wood, salt, and soda kilns.  You can buy zirconium oxide on eBay  - ten pounds for about $100, which should be enough to spray a good-sized kiln when combined with 5% ball clay as a binder.  

My friend Joe Winter (was partners in the big anagama at Great Basin Pottery with the late Paul Herman) built a propane-fired softbrick salt kiln seven or eight years ago, and it has held up pretty well with frequent firings.  He sprayed on a liner, and I don't remember what he used, but I could find out. 

You don't want to saturate the brick all the way through, because that would greatly diminish the insulating properties.  Nor do you want to build up the coating heavily on the surface, because that would likely peel off from differential expansion/contraction.  I wish someone would do some solid research on this.  It's not anything I want to undertake.  My firing costs are high, but I don't fire very often, and the first few pots out of the kiln pay the fuel costs, so I can't complain.  
- Vince   

Vince Pitelka
Potter, Writer, Teacher
Chapel Hill, NC
vpitelka at dtccom.net
www.vincepitelka.com 
https://chathamartistsguild.org/ 

-----Original Message-----
From: Clayart <clayart-bounces at lists.clayartworld.com> On Behalf Of Roxanne Hunnicutt
Sent: Sunday, June 11, 2023 11:26 PM
To: Clayart international pottery discussion forum <clayart at lists.clayartworld.com>
Subject: [Clayart] Oh, this is kinda sad. Rox in oregon

Hey all my mud loving friends:
I did well and gave away my big gas kiln. I’m 74 and cleaning up and out!

Now I have that space and always have wished I could fire with soda.  I
could buy a soda kiln. What would that involve?   Who has a small soda kiln
plan?

Rox
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