I had no idea what I was in for, but it's been an amazing experience.
Building My Dream Kiln
the kiln--the frame
It took me awhile to find someone to agree to weld the frame together for me. I was willing to hire someone, but not sure where to look for a reliable welder. A friend of a friend decided that he would supply his expertise and do the welding for me, if I directed, because he knew nothing about kilns. I invited him over to see the kiln that my potter friend had built, to give him an idea of the scope of the job. Then, after detailed discussion of the frame construction, I searched out and found a supplier for the steel tubing and angle iron I needed. What an interesting sight to see giant wet-saws cutting 20 foot pieces of 3 inch tube in half like they were butter. After getting the steel, I rented a "chop saw" and a generator powered welder and my welder friend came out for the day. He taught me how to use the chop saw properly and then grind the sharp edges off the cut steel with a hand grinder.
|Then I would put
the frame pieces together and tell him where to weld. Another friend of
mine volunteered to be a third hand the two days we spent welding, and her
help was invaluable. I started the frame by building three cross-layers,
the bottom, the layer that holds the brick and the top, and then we attached
uprights to put it together.
Cyndi volunteered to be a third hand the two days we spent welding, and her help was invaluable.
|The cart was then built, upside-down, and set up on unattached tracks to attach the door frame and test it out.|
| The next thing I focused on
was the burner system. This welding job was pretty special, it needed to
be sealed totally for the gas line. I called my gas company (propane) and
they directed me to someone who could fabricate what I wanted to build.
|I took the parts out, laid it out for the guy and two days later he had built it and air tested it for me. I bought the actual burners themselves by mail from a source in Los Angeles. Then, the propane guy came out, scoped out the job and came back and connected the venturis to the system.|
| At this point I also ordered
sheets of galvanized steel for the outer surface of the kiln. It serves
both functionally-holding the thermal insulation and bricks in and visually,
being much more attractive to look at than the outer layer of the kilnwall,
which is rigid thermal insulation. When that was ready, I hired a welder
from the want ads, to come and fix a few minor adjustments and put the galvanized
steel into the frame. Unfortunately, the film was defective from this point
'til after the kiln walls and chimney are bricked.
The first thing I did, to start filling in this blank frame I had constructed, was to line the sides and bottom layers with thermal insulation. This kiln design has six burners coming up from the bottom along both sides. I had to cut the port holes for the burners in the insulation. It was then I realized that I had miscalculated and made the burner assembly 5.5" too wide, necessitating a crosspipe being shortened. Lining the kiln was easy, as the insulation material is much like layered cardboard and very easy to cut to fit. The only drawback about working with the insulation is the itchy dust. When the insulation layer was all in, we started on the walls. The side walls went fairly quickly and smoothly but the back wall, with the flue, chimney and damper to think about went a bit more roughly. I was unhappy with the back wall after the first try. After discussing my design with an online friend, in particular the meeting of the cart and the kiln at the back wall, I decided to take the back wall down and rebuild it, changing the cart/kiln seal and fixing the crookedness that bothered me. The second incarnation of the back wall was much better. My flue design is Nils Lou's venturi design from The Art of Firing, with a horizontal damper up above the flue.
|Next I had to build my arch. This was a challenge. I wrangled Gary to help me build an arch form out of plywood, cutting arcs of wood and running strips lengthwise. I used Fred Olsen's book to determine how many bricks I should need. I decided to cut the sideskews for the arch, as I had forgotten to order them with my other brick.|
Rusty Wiltjer's suggestion to load the cart with hardbrick on top to hold the softbrick in place...was brilliant!
|I was confused, at first, as
to how to determine the skew brick shape, but after some discussion of the
process with friends I bought a mitering square and laid the archbrick out
marking the skew angle on paper, which I used as a guide to set the mitering
square used to mark each skew brick.
| Now I was ready to FIRE,
I thought. I realized after I loaded up the first bisque load that I hadn't
put the pyrometer in. I used cones and although it fired quite unevenly
(06 flat on top barely down on bottom), I was pleased with the speed of
firing and how easily I seemed to get a feel for the burner adjustments.
I pretty much left the damper alone for the first few firings. I decided
to test my cone 6 oxidation glazes to see what they would do in a gas kiln.
I got some wonderful results in the first two firings, even though I overfired
them to cone 8 on the top with cone 6 at the bottom. Meanwhile, I discussed
the kiln with my buddies online and they gave me some ideas for some "tweaking"
to do on it. I decided to make a couple changes, eventually, but will be
firing it, meanwhile.
I will continue to document this process with photos, and eventually finish up this ongoing page with some beautiful glazed loads!
Goddess of the Kiln
Oh great and mighty goddess of fire
we dedicate to you this day a new kiln
Lovingly built by the humble hands of your servants
We pray that in your continued firing
you will only flame our creations with
creative scorch marks and never make them crack,
That you melt our glazes lovingly and evenly,
without runs or drips, unless they look really cool
We ask that you grant us the will and patience
To allow our work to dry before entrusting them to your care
To not view your work until you have cooled your fiery rages
To properly wash all shelves, just in case
In return, We the worshipers of your great and mighty gasses,
Promise to always wipe the bottoms of our creations and
to never let you overcook,
To keep your burners in good repair, for we would not want you
to ever go hungry or blow up.
Brandy Dickerson 1997