Kazegama Rebuild – January 2016

For 15 years, my Kazegama was bolted to a trailer which allowed me to travel to different venues to put on Kazegama workshops. It has gone through many adjustments and changes due to the knowledge gained over many years of firing.

But over a year ago, I had cervical spine surgery to stabilize the C2 bone in my neck due to a congenital defect that was causing damage to my spine. I am now the proud owner of a plate bolted to the base of my skull along with two rods that are screwed from that plate, down to my C3 and C4 bones. As a result, I am unable to turn my head and back up my Kazegama trailer without difficulty. I am now limiting my workshops to monthly events at Aardvark Clay & Supplies. That being said, I am doing extremely well and doing all the things I have always done (except turning my noggin….). I am in excellent health.

Once I decided to remove the Kazegama from the trailer, I started thinking about all of the changes I could make to the kiln. I decided to make the following changes:

1. Place the burner manifold on the wider, right side of the kiln in order to create more spacing between the burner ports. This allows for larger pots in the firebox section of the kiln and a shorter distance from the front of the kiln to the rear of the kiln. This will achieve a more balanced distribution of heat and ash throughout the kiln.
2. Install additional flues in the lid to provide the required flues across the rear of the kiln, have better balance of the lid as it is raised, and provide an additional front flue for future testing involving reduction cooling and the introduction of charcoal into the firebox area.
3. Cover three of the four outside walls of the kiln with galvanized sheet metal skins courtesy of Geil Industries to cover up the scars of use and give the kiln a more finished look.
4. Place the kiln on dumpster wheels and attach them to the legs of the kiln with a length of channel that acts as a step for those that are vertically challenged.
5. Add metal rings that cover the openings of the burner ports. These will hopefully create a stable mount for the burner port tubes and reduce damage to the ports caused by shoving fiber plugs into the ports. (These rings starting distorting early on during the first firing and are not a good solution).
6. Line the kiln walls with 1″ Corelite kiln shelves, the floor with dense, 1″ corderite kiln shelves, and cut out flue openings in the existing shelves that are suspended under the lid.

Well, after 80 hours of labor during the December break and a few weekends in January, the kiln was completed.

Burners tubes are lined up and deck-screwed into a wooden 2×4 prior to welding onto 2″x3″ tube steel manifold. On the right is the old hot face of the firebox with burner port holes.

The old hot face kiln shelves and fiber were removed and replaced with new fiber blanket where needed and Corelite kiln shelves which cover the fiber blanket and protect it from the corrosive attack of the ash.

9 gauge nichrome wire is fed through two holes made with a masonry drill bit and twisted off around the outer layer of 9 gauge x 3/4″ expanded metal.

Here is the new interior and floor coming together. The old burner ports were plugged with fiber blanket.

The floor shelves lock in the bottom portion of the wall shelves. The new flue frame is laid out and the bricks are placed inside of the frame in order to spot weld the location of the frame parts. The heavy expanded metal inside of the frame is removed with a hand held grinder with a metal cut off blade. Some fiber is placed on top of the existing layer of fiber within the frame where it will sit under the brick in order to keep heat from encroaching on the metal frame. Once the bricks are in place, a long sharp knife is inserted along the side of the bricks and an opening is created for the flue.  Transition from fiber to brick construction can be found at https://kazegama.com/soda-kiln-construction/

Once the flue opening is exposed by cutting out the fiber, the old lid shelves can be marked before removal. Then the lid shelves are removed by cutting out the nichrome wire ties and gently removing the lid shelves. The shelves are cut with a tile saw to match the opening of the new flue.  Then they were re-wired with 9 gauge nichrome wire.

Before the burner manifold was completed, it was placed in its holder and the location of the burner ports were marked off by drawing a series of lines around the burner tubes at the wall. The burner manifold was removed and a long masonry drill bit was used to drill from the center of each circle through the wall.

A long masonry drill bit was used to drill from the outside to the inside, where the hole from the bit became the guide for the 3.5 inch hole saw. There is a drill bit inside the head of the hole saw that keeps it on track. I use a medium duty combination metal/masonary hole saw that is relatively inexpensive to purchase and works great in Cordite shelves that are rather soft as a material. It is easy to tweak your wrist with this set up. Do not hold the drill motor in one hand and like a gun. When it catches on the wall, the drill motor will kick so hard against your hand that you can do some serious damage to your hands. So hold it with both hands, but sandwiched between them without using a pistol grip.

Before and after with new burner port rings.

Some winches come with a fitting that allows you to place a hook into a drill motor and crank the winch without much effort. I could not find a fitting for this winch so I removed the handle and just welded a loop onto it.

There is one row of 3 shelves across the back which are 3-posted. The front facing bricks act as an ash and flame deflector as well as shelf support.

Here is the very simple wiring of a Grainger blower part# 6FHX4. Each burner has a 1/4″ ball valve with 3/8″ copper compression tubing.

I need to work out a better electrical supply but this has worked for 15 years. Wire ties are used to hold the power cords in the sockets so they do not pull out when over-heated. Two pieces of 1″ angle iron were welded to the top of the burner tubes to hold heat shields made of Corelite kiln shelves.

There is a lot of back pressure in these burner ports and the metal rings survived but did not do well. I need to greatly enlarge these burner ports and insert ceramic flanges that shield the metal work.

Everything gets loaded into the kiln after unloading and clean up have been completed. Then off to the kiln shed.

First firing of the Kazegama rebuild on January 23, 2016

More information and a thorough description of building the Kazegama can be found at the Building the Kazegama page.