Monday, February 14, 2011

Small Salt Glaze Test Kiln Construction

Last week I built myself a small makeshift top-loading brick stoneware kiln, that would give me the opportunity to test out salt glaze recipes in small amounts. It is fired initially by wood and then by a diesel jet burner going in at the side. I was able to put it together in one afternoon, using a scaled-down layout from the one that I used on my big kiln. This one has a kiln shelf as a roof and no arches.The walls are a single layer of fire bricks, as this cuts down on a lot of bricks, and should be enough for a small test kiln.  Anything bigger needs to be double brick walled.

It's the same size as my small gas kiln and would make a great hobby kiln/test kiln. I'll be interested to compare it to the small gas kiln in terms of fuel economy. I've used fire bricks throughout (house bricks will just melt at these temperatures) laid on a bed of cinder blocks. The kiln reaches temperatures of over 1300 degrees Celsius, so it is suitable for any kind of stoneware.

Here are some photos showing four stages of the construction:

The first layer of fire bricks, sitting on a foundation of cinder blocks

The second level, showing the firebox and throat into the kiln which runs under the floor.
Side view. This is where the diesel burner goes in, under the chimney. It goes under the floor combustion space before it gets into the kiln.
Top view, showing kiln chamber at the front, chimney, and firebox at the rear. There is a salt port in the top right hand corner, where the salt is thrown in over the flame, in front of the bag wall. This photo shows three layers of bricks in the main chamber where the pots will sit. After this I kept adding layers till I got the finished height, adding one spy-hole in the middle, and a little hole for the pyrometer up near the top. There will be a flue for the chimney at the rear.

Side view showing kiln shelf covers in place, and chimney - I will add a stainless steel flue chimney as well, before firing, to create more draw.

I hope to fire this one in another week or so, with some new salt glazes and subsequent oxidisation and reduction firings.

There are some plans similar to what I used here. They were originally taken from 'New Zealand Potter' magazine but unfortunately I forgot to write down a reference.  Here is a plan showing a cutaway view of the kiln in action:


Michael A. Ray said...

I love your work. This kiln design seems perfect for me as I only have one burner. I have adapted this design to burn propane rather than diesel and I am having horrible problems. I cannot even melt an 04 cone. Are there any suggestions that you have? My first instinct is to double the chimney space.


Michael A. Ray

Wil-jolNda said...

Tried out the design fired up to cone 08 than it sticks. Put forced air into the brick fireplace , marginal temp increase.
What’s wrong....???any better design?
Thanks a lot