32" build in Calgary, AB - pompeii neapolitan

[IH123]

I today, cut enough dome brick cuts to complete the full 3rd course , and also prepared the arch legs by cutting the top brick of the arch leg to the required angle. I did not mortar any bricks today but will do next week, I chose to construct the inner arch curve, only after the dome reaches 3rd-4th course where they can meet, to have a clear view of how it has to be (and will use the trammel to mark the inner and outer cuts on arch curve while using full brick to bridge between arch and dome). picture from today:

[david s]

Be sure to place some wedges underneath your timber arch former, so when removed it will drop and facilitate easy removal without disturbing the arch.

[UtahBeehiver]

Plus one on Dave's comment, 3/8 - 1/2" is a good release wedge size.

[IH123]

I have to cut my inner arch curve voussoir brick to allow combustion gas to swirl upwards on exit, so all smoke can be directed to the flue gallery as soon as possible without having to allow velocity to shoot it forward towards the mouth, this may require a bit of padding to my arch work form on top, which I can do with additional shims, as the arch work form was designed for flat cut (I made it before considering the aerodynamics of smoke) :

[david s]

You shouldn't really need this because the velocity of the smoke once the flue is drawing well will leave the sharper angle better than a rounded one. The corollary is the transom of a speed boat where the sharp angle performs better than a rounded one once the velocity increases a bit. "Duck tail" car designs work on the same principle. All ovens will smoke a bit at start up, until the flue warms sufficiently to create draw.
I once had the experience of operating my mobile oven at a market where the stall-holder next to me was selling hand knitted wares like baby booties. I was so worried about the smoke causing issues for her goods, particularly at start up. I discovered by starting a tiny fire and adding really small amounts of wood to progressively build the fire, that it is possible to do a completely smokeless firing.

[Giovanni Rossi]

One additional comment on the arch form. With the top open, it's possible some mortar may squeeze into that space effectively locking the form in place, even with a shim. If that happens, you don't want to force it free. Shouldn't be an issue for you as it looks like your assembly can be dismantled from either side. This is more a caution for other builders when designing their form.