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space age materials in a salt kiln

updated thu 14 feb 08

 

Mark Cortright on mon 11 feb 08


Another potter and myself built this kiln back in the early 2000's. It's inspired by Mel's article in
CM on salt and fiber/soft bricks and ITC.
I figure I'll take some hits on fiber and soft brick in a salt kiln but hey it's working and it's cheap to
fire and fast. You have to keep your mind open for learning.
The roof is a bit different - it's an arch so it keeps the fumes moving away. I thought about this
roof for 20 years before building. We elevated the base on heavy steel mesh on top of concrete
cinder blocks. This keeps it cool underneath and very easy on the back to load. We lined the
floor, flue, bag walls, and ports with hard brick. The exterior is hard brick. The rest of the interior
is soft brick walls. The door is a 360 degree swing-away all-fiber door made from heavy steel.
The roof is a single home-made module made from 4-foot wide fiber. I realize this seems like a
different animal but I have done alot of kiln-building in my life. New thinking was what Mel's
article was about and I ran with it. Pots are pre-bisqued, then loaded on dry-pressed high-
alumina shelves. The kiln is 4 burners (natural draft)-The flue and chimney are Nils Lou's double
venturi setup-brick up to 10 feet then stainless steel another 8 feet. To get to tempature in about
6-7 hours with the super-insulated materials. We boil water and saturate it with salt, then spray it
in the burner ports and 4 spray ports with special brass spray wands in pump sprayers. With a
digital pyro we work the temps up and down with the spraying of salt to let the temps
regain between salting cycles. This method really moves the vapors around and we have
very few dry spots. We have had great results in about 10 loads so far. As this is
therapy we seem to only do a load or two a year..
A few side notes - the kiln is originally sprayed with ITC everywhere - now it's sprayed with a
formula I'm perfecting that works really well (better than ITC) to repel salt on bricks and fiber.
I may try to market it, as it's way cheaper than ITC. We also have to spray (coat) parts before
every fire and have learned a lot on what works well and what does not. I would change a few
things in a rebuild.
We cooked the roof (shrunk) about 4 fires ago overfiring a tad. We now deck the
top with those 14x28 thin silicon-carbide (knock-offs from china) shelves as we get a little fallout
from the fiber which is spalled pieces of ITC coating.

There are photos of this kiln posted at June Perry's sodasalt yahoo group
http://groups.yahoo.com/group/sodasaltfiring
The photos are here
http://ph.groups.yahoo.com/group/sodasaltfiring/photos/browse/32b1

Mark Cortright
www.LiscomHillPottery.com

Ivor and Olive Lewis on tue 12 feb 08


Dear Mark Cortright,=20

Would you please confirm that you are using Sodium Chloride (NaCl) as =
your vapour medium.

Good to know of your success.

Best regards,

Ivor Lewis.
Redhill,
South Australia.

mark Cortright on wed 13 feb 08


On Tue, 12 Feb 2008 16:07:27 +1030, Ivor and Olive Lewis wrote:

>Dear Mark Cortright,
>
>Would you please confirm that you are using Sodium Chloride (NaCl) as your vapour medium.
>
>Good to know of your success.
>
>Best regards,
>
>Ivor Lewis.
>Redhill,
>South Australia.
>
>______________________________________________________________________________
>Clayart members may send postings to: clayart@lsv.ceramics.org
>
>You may look at the archives for the list, post messages, change your
>subscription settings or unsubscribe/leave the list here: http://www.acers.org/cic/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.com

Dear Ivor Lewis
We use our salt from a 50# bag of soduim Cloride- which I get at a restaurant supply
we boil water and measure out the salt so we know how much we use per fire. We saturate the
water until it will hold no more salt then add a little water. Strain solution then put into garden
sprayers which have the tips retro fitted with special ends to take the heat.The tips are brazed on.
The trick is to keep the spray going while inside the kiln to cool the tip.. This really gets the salt
vaporized RIGHT NOW and pots get an good coating . This spray can really eat up bricks sprayed
directly on as you know. Best to have hard brick targets. Hope this clears that up. I can (will) send
you some photos of kiln.
Mark Cortright
www.liscomhillpottery.com

Ivor and Olive Lewis on thu 14 feb 08


Dear Mark Cortright,
Thank you for your complete and comprehensive answer to my question.
Yes, I understand that such a process will melt and then vaporise the
Sodium Chloride almost instantaneously. Yes, there will be aggressive
chemical activity.
Best regards,
Ivor Lewis.
Redhill,
South Australia.


----- Original Message -----
From: "mark Cortright"
To: ; "Ivor Lewis"
Sent: Wednesday, 13 February 2008 4:45
Subject: Re: Space age materials in a Salt kiln


> On Tue, 12 Feb 2008 16:07:27 +1030, Ivor and Olive Lewis
wrote:
>
> >Dear Mark Cortright,
> >
> >Would you please confirm that you are using Sodium Chloride (NaCl)
as your vapour medium.
> >
> >Good to know of your success.
> >
> >Best regards,
> >
> >Ivor Lewis.
> >Redhill,
> >South Australia.
> >
>
>_____________________________________________________________________
_________
> >Clayart members may send postings to: clayart@lsv.ceramics.org
> >
> >You may look at the archives for the list, post messages, change
your
> >subscription settings or unsubscribe/leave the list here:
http://www.acers.org/cic/clayart/
> >
> >Moderator of the list is Mel Jacobson who may be reached at
melpots2@visi.com
>
> Dear Ivor Lewis
> We use our salt from a 50# bag of soduim Cloride- which I get at a
restaurant supply
> we boil water and measure out the salt so we know how much we use
per fire. We saturate the
> water until it will hold no more salt then add a little water.
Strain solution then put into garden
> sprayers which have the tips retro fitted with special ends to take
the heat.The tips are brazed on.
> The trick is to keep the spray going while inside the kiln to cool
the tip.. This really gets the salt
> vaporized RIGHT NOW and pots get an good coating . This spray can
really eat up bricks sprayed
> directly on as you know. Best to have hard brick targets. Hope this
clears that up. I can (will) send
> you some photos of kiln.
> Mark Cortright
> www.liscomhillpottery.com