Kiln Construction

Phase Two

In October of 2015, I began to move earth and construct the arch of the kiln.  I wanted to try something different for my arch.  

Chain and catenary arch construction is done by hanging a chain to trace the shape that it makes to build the arch.  That makes a strong arch but it'll eventually fail, collapsing, in the bottom third of the wall.  

A barrel creates an arch that is any part of a circle.  When it's initially built, it will still be a curved arch, but once it's fired, everything will expand and the top will flatten out in cooling and eventually fall in. 

A barrel creates an arch that is any part of a circle.  When it's initially built, it will still be a curved arch, but when fired, everything will expand and the top will flatten out in cooling and eventually fall in.   

The point for me, was to find an arch design that's in between the catenary and barrel design.  I found that bending a pipe will create a line right between the two.  I think it will be a stronger arch--I may have created a new problem too but we'll see! 

I've never seen the arch building technique that I've used done before and I'm confident it will work.  I spent several months working out the details of my arch design on my own and decided to go for it. 

Digging the foundation of the kiln was much harder than I thought it was going be.  Not the digging itself, because it was done quickly with a backhoe; but calculating the depth and step heights were a challenge because they had to be planned perfectly.  I began to realize I had to know almost everything about this kiln in order to dig this hole.

Digging the foundation of the kiln was much harder than I thought it was going be.  Not the digging itself, because it was done quickly with a backhoe; but calculating the depth and step heights were a challenge because they had to be planned perfectly.  I began to realize I had to know almost everything about this kiln in order to dig this hole.

The green line on the plywood is what a catenary arch would have looked like.  My method used pipe. Barrel arches eventually flatten out and fall in.  A catenary will eventually fail in the sides and collapse.  All kins will eventually fall in, but I wanted to try something different.  We'll see, I may have solved a couple of problems or maybe I just created a couple more!   

The green line on the plywood is what a catenary arch would have looked like.  My method used pipe. Barrel arches eventually flatten out and fall in.  A catenary will eventually fail in the sides and collapse.  All kins will eventually fall in, but I wanted to try something different.  We'll see, I may have solved a couple of problems or maybe I just created a couple more!   

 I had already almost completely planned the kiln by this point, however I did end up spending a lot of time working on the depth and steps to ensure the arch was not out of the ground.  I did not want the arch out of the ground for two reasons: 1. to save money and buttressing through allowing the Earth do the job, and 2. I wanted to be able to stand at the tallest part of my kiln and still see the person stoking on the other side.  

I started by standing the ribs up and secured them in place. The strips are then screwed down into the ribs.

I started by standing the ribs up and secured them in place. The strips are then screwed down into the ribs.

When the strips were screwed into the ribs, the form became irregular. So I had to sight each strip to make sure I wasn't altering the natural more perfect curve of the strips.

When the strips were screwed into the ribs, the form became irregular. So I had to sight each strip to make sure I wasn't altering the natural more perfect curve of the strips.

Having completed the arch form and sighting every single strip, I was satisfied to move on to the next phase of the build--bricking the arch.  Stay tuned for more.