New Oven Flue Size

[MattP]

Thanks for your prompt reply UtahBeehiver.

I guess 6" is the way to go. I was told that it may be too big for my application of approx. 2m height.
I will take on your suggestion/recommendations re. CaSi board and dome insulation.

View 1 represents the front elevation/entrance and in particular the decorative tiles I intend to use.
View 2 is a cross section of the oven which shows the 75mm thick casting, 25mm insulation blanket and finally the render.
The base, starting from the concrete slab, consisting of CaSi board, 40-50mm refractory tiles.

I hope this explains my design.

Matt

[UtahBeehiver]

As far as casting, David S is our resident expert. He can give you good insight on cast ovens. IMHO, 850mm = 33.5 inch diameter oven should use a 6" flue, The FB plans recommend 6" on ovens 32 - 36" ID.

The floor and particularly the dome insulation seems light, 40mm (1.5") CaSi board should be a min of 2" or abt 50mm, Same with the dome, 25 mm pretty light. View one does not show the floor insulation under the dome, view 2 does so just making sure you have the dome insulated away firebrick or the concrete hearth or these act as heat sinks.

OasisCDM is from Werribee so he can give you insight on material sources

[MattP]

Hi All,
I am new to this forum from Melbourne - Australia, and hope to share some information and also learn from other enthusiasts.
I am in the process of finalising the design (own design) for my wood-fired oven.
It will be a cast refractory concrete 850mm internal diameter, with flue extending past the protective all metal roof structure.
The flue total height is approx. 2m.
Here is the dilemma/question for the experts.
What is the most suitable flue size (diameter) for my application?
I have been told 6" diam may be too large and may draw all the heat out of the oven and perhaps 4" or 41/2" diam may best suit.
A section of twin skin flue will be used at the roof penetration.

What do you think?
Please refer to the attached design.
Matt