Between now and “then” things have come along. The build of the oven is now basically complete, or at least the wiring is now all good, and the oven is operational! No boards have been soldered just yet – now waiting on a couple stencils to arrive, but close indeed…

For the record here are some photos:

Points to note for those interested are:

  • Three main solid state relays to control the heating elements.
  • The oven has a convection fan, so there is a small 2 A solid state relay mounted below the third main relay (which controls the boost element(s)).
  • Two 550 W cartridge style heater elements are installed as the boost “heater”, wired in parallel. It’s a relatively large capacity oven, at 20 L or so, thus potentially the need for extra heating capabilities. Worst case is that one element can be disabled / removed.
  • The original oven mode selector was re-purposed to be the power switch: all bar one positions are power off, with the remaining one, of course, being power on.
  • There’s a proper chassis mount +5 V power supply screwed to the front panel (conveniently using a couple of holes “left over” from removal of the original power/timer control). While maybe convenient, strapping a wall-wart type supply to the case seemed a little unprofessional. Especially given the chassis mount power supply cost much the same anyway!
  • The original clamp style power cord entry bushing was replaced with an IEC 60320 C14 male socket.

What next? The list still contains a couple of things to do:

  1. Insulating the oven with a couple of layers of suitably high temperature welding blanket; Kapton tape around the edges, etc.
  2. Seal the mid-construction seams with high temperature silicone – these seams are not internal to the oven cavity, but also not external to the shell.
  3. Fit the aluminium tray.
  4. Perform test runs of the temperature profile.

Oh so close…