[Clayart] Cone 10 Orange Peel effect using only SODA, and how to protect Arch Softbrick

[Vince Pitelka]

Hi Helen - 
That's what I was talking about - using the 80 Zircopax-20 Kaolin mix to protect the softbrick.  If you apply that to your arch, follow the instructions I specified, and do give it a coat of shino to seal the surface.  I make no guarantees, but this should work as well as anything.  Do keep in mind that salt is far more corrosive on the kiln interior than soda. Whatever you use to coat the interior, it will break down faster if you charge with salt.
- Vince

Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka at dtccom.net  
sites.tntech.edu/wpitelka/


-----Original Message-----
From: Clayart [mailto:clayart-bounces at lists.clayartworld.com] On Behalf Of Helen Stone
Sent: Tuesday, May 8, 2018 3:26 PM
To: Clayart international pottery discussion forum <clayart at lists.clayartworld.com>
Subject: [Clayart] Cone 10 Orange Peel effect using only SODA, and how to protect Arch Softbrick

Hi Robert Harris and all you clay folks, Thank you so much for your explanation on spraying soda only to get the orange peel effect.  Obviously the guy wanting heavy reduction would be closing the damper, would others be also closing the damper during the soda spray, in order to contain the soda or would they somewhat open the damper, to encourage the soda to flow more?

Is there any way that I could use Zircopax with, say maybe 20% Kaolin to paint on as protective coating for my arch softbrick, to protect it from a
bit of salt?   I'm reviewiing the situation, as Fagin says in the movie,
that sort of Dickensian musical many years ago.

Re:  the kind person trying to help me see my way through damper management and a murky atmosphere, some kiln specifics:  my kiln is about 18 cu. ft, maybe 32 or 33 inches wide, very shallow, 27 inches deep, the sprung arch at the top is 35 inches high.  Stacking space is only 8.6 cu. ft., as I have two, seven inch wide combustion chambers , one on either side of the stacking space.  The two burners are located, one beside the chiimney in the rear, and second is in front to the right of the door, diagonal to the other burner, for turbulence.  I could only see the cones on the bottom shelf after midway through the 12 hour firing, could not see the cones on higher shelves.  During the firing the kiln stalled around 1100 Celcius for an hour.  The pyrometer also seemed to stall at 1200 Celcius, but when \i accidentally whacked it, it sprung up to 1250 right away, but then did not register the highest temperatures.  It started working again at around 1250 on the way down, I downfirred for about 30 minutes after reaching over cone
10 with heavy reduction, for the hell of it, as I had not, I thought, reduced really during the firing.  The burner flames looked good to begin with, some blue colour coming out shading to orange, but seemed quite orange all the rest of the firing.  The primary air was kept open all the way, but I did block up the secondary air, i.e. the burner ports, quite a bit, because I had built them larger than normal because of my 5,000 ft.
altitude.  Also I had build the chimney one brick deeper than the normal 9 inches inside because of the altitude.  I modified this after the initial , bisque firing for my clay stamps, by inserting two bricks into the chimney floor.  The rest of the chimney remains wide until it reaches the damper, where it gets small again, the regulation 9 inches wide inside.  It is a tall chimney.  Enough clues.

Helen in Ecuador, on Rio Yambala
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