Building the form for the arch

Once I had cut the catenary curve into two identical pieces of plywood, I started building the form for the arch my connecting the two pieces together with a series of wooden battons (70x30mm Pine).

Once the battons were in place I attached a thin sheet (3mm) of ply over the top of the frame. The finished form will be used to hold up the brick arch while it is being constructed. The form will be taken out, of the kiln, once the arch is completed.

As I will be transporting the form from my home to 'Spring Creek' some 375kms away I have made sure it fits neatly in a trailer.

Calculating the number of arch bricks needed

After I had drawn the catenary curve on a large sheet of plywood. I cut it out using a band saw and used it to calculate the number of straight and arch bricks needed. I used the spare bricks the ANU ceramics workshop had on hand to see what was the right combination of bricks, to fit the curve, before I ordered my own bricks.

Building the Spring Creek Kiln: Calculating the arch

So that I could  construct the arch of the Spring Creek Kiln easily I decided the arch would follow an inverted catenary curve. Kilns of this type are commonly known as catenary arch kilns. To plot the curve I used:

• a large sheet of plywood
• two nails
• a chain
• a can of spray paint

I suspended the chain between two points and adjusted the length until I got the desired depth in the curve (or once inverted, the height of the arch). I then sprayed the chain with  paint so I could mark the curve.

Hanging the chain between two nails to create a catenary curve.