We’ve done quite a few round ovens over the years. Here are some of our favourites:
One of the most challenging moulds that we’ve ever made was for this project. We wanted to reference the existing raised paneling in much of the house. We took meticulous measurements, and in the end decided to proportion the panels slightly differently.
Making the moulds was a multistage process because of the complexity of the design.
The first step was to make a positive wooden master mould (1). This mould obviously had no beading. From that we made an initial negative plaster mould. We planned to carefully drill rounded indentations into this mould using a drill press to create the beading (2a). It took quite a long time to find the right bit and determine the correct depth for the holes. Some of the test holes and mistakes can be seen in this photo. In the end we were able to find a router bit that worked perfectly. That gave us a master negative mould (2b). The final design called for 125 kachel, so we needed more than just one. From the master negative mould we cast a positive out of silicon (3). Silicon is more durable, and would allow us to more easily make multiple working moulds.
We ended up making a batch of eight working moulds. Two or three moulds ended up breaking during production, and needed to be replaced.
The moulds were pressed full of clay by hand and left to sit overnight. Kacheln were removed the following day.
After firing the pieces twice (bisque and glaze), the kacheln were packed up and shipped off to their final destination!