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first gas firing in 7 years!...

updated thu 29 mar 01

 

Ann Brink on wed 28 mar 01


Hi all,

I finally fired up the gas kiln last Saturday, with MUCH excitement. I've
had it for years, but it's had one problem after another (different long
story) so using the Skutt 1027 has been sooooo easy, and I've
procrastinated. If you don't want to read all the rest, but like to see
pots, click on
www.impulse.net/~billann/gasfiring.html

The kiln is an updraft, with interior dimensions of 32" high, 36" wide, 28"
deep. I got ^10 in the top and 9 just starting on the bottom.

The temp. seemed to stall the last 2 hours, so I kept dinking around with
the flue opening-sliding my bricks to alternately increase or reduce the
size of the opening. The pyrometer needle seemed to climb a little either
way at first, then go down. Finally I could tell by the witness cones that
I had reached temp- I think it was time that did it between 9 and 10. So I
turned the burners down a little and fired down, then shut two of them off
until it was about 1500 degrees, then closed off the top and turned the
other 3 off.

Anyway, I mixed up a few new glazes of course, and glazed several pots
with each one. Figured the whole firing was a test. Here are a few
results:

1. A glaze of 98% Mt. St. Helen's ash and 2% Titanium Oxide was lovely-
smooth, satin finish, no running or crazing. Yes, it's brown, but has tiny
orange flecks. Next time I will include larger grains of the ash instead of
straining so finely- might get more variation. Thanks to Pamala Brown for
posting this last June. ( I rounded off her #'s)

2. A blue celedon posted by Craig Martell last August 1st (Thank you!) is a
keeper too.
I actually have some Kingman feldspar, one of it's ingredients. This turned
out blue-gray, no crazing, nice and smooth. Next time I will use it on a
piece with more texture or carving.

3. I tried a shino recipe calling for Nepheline syenite-70%, China clay 30%
, and, as called for, added some Frit 3110- an additional 20%. on This
turned out really DRY. I did sub. EPK for the china clay--could that be the
reason? I didn't apply it thickly, thinking it would be orangish where it
was thin. It was, in some areas, but mostly whitish. I need to add some
flux to this bucket.

4. A flambe I used on several pieces just stayed whitish, crazed, and
started to run. Also got a dirty line at the bottom edge. This is the
recipe I used:
Custer Feldspar 73
Gerstley Borate 11
Whiting 11.5
Flint 5.
Copper Carb. .5
Tin oxide 1.

Can anyone suggest something to change about this recipe, or did I not have
enough reduction at the end?

The Westwood (now Laguna ) commercial Iron Red worked as expected, also the
WC 525 #1 Temmoku was great, except I got a few bubbles in the black part
where it was thickest. The blue-brown, WC557 looks good, mostly a satin
chestnut brown with black or blue where double dipped. (Sorry, internation
potters, about these very western US glazes)

Well, if you've stuck with me this long, thanks for reading---nobody in my
non-computer world is really interested in this many details (but at least
they like my pots!).

I have been picturing the paths I think my flames take in the kiln, and have
some ideas for changing the stacking arrangement, also want to fill it more-
I got in a hurry.

I've added a link called LATEST GAS FIRING to our website(lower right-hand
corner), the first URL one listed below, if anyone would like to see the
kiln, which is made of castable material, and some of the pots. I would of
course love hearing
from anyone who feels like commenting!.

Ann Brink in CA