Fnbrokens Corner WFO in Canberra, Australia

[fnbroken]

My first attempt at 3D modelling - stainless steel components to be ordered...

[JRPizza]

Wow, you sure picked cad up fast - have you had previous experience? I'd like a copy of your model when you are done to add to my collection, if you don't mind. If you ever get access to a 3D printer you can export models to print - it would be kinda fun to print a small oven, I might have to give it a try.

[fnbroken]

No experience, just don't mind systems - once you crack the basic code - particularly the order in which to constuct a part - it starts to flow. Then when you can't figure something out, someone else has so Google becomes your friend. Starting is the hardest - when it is all too confusing. That said, I have spent quite a few hours on it!

Happy to share the plans to anyone interested it's a pity their isn't a 'reference' library of distances and relationships. If there was, most of the measurements are based on a few key lengths and this could be quickly and easily modified.

Ive been very distracted by the CAD - I can't remember what questions I've asked, and if I've figured it out or need to ask again!

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Ash Chute / SS Thermal Break question:

Could I combine these? Have the SS TB removable (couple tabs on the very outside) to lift it out as required? Essentially it would be like a plug to the ash chute hole - Would this still provide the same TB qualities?

I would need to make the TB 50mm wide...

Thoughts?

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A visual of what I mean...

[deejayoh]

Personally, I never saw the purpose of an ash chute. I clean my oven between firings. Sweep it out in two minutes right into a big dustpan. Never wished I had one.

[fnbroken]

Yeah, that's what's getting me DJ - there is little feedback on if they are a useful thing or not... further mulling/chiming in from others would be handy about now...especially those who have one and what you think of it.

As an aside, I just finished reading the 'show us ya door' thread you started as it popped up in new posts... some great functional and really aesthetic doors to get ideas from...

Stainless inner surface, calsil blanket, ceramic rope seal, handles attached to outer shell only, thermometer, timber facade. What looks like a stand/bracket to hold it tight against the inner vent - perhaps one of these would make that job easier... I figure Im going to be getting a few things made in stainless, so a CAD to assist...

My current WFO has a thermal glass window - looks pretty - but im assuming it isnt very practical for heat retention...

[deejayoh]

get a big green egg/Kamodo grill gasket to seal the door. Works much better than rope gasket. If your door is deep enough, no need for any stand or bracket. Mine is 2" deep and it never moves

[fnbroken]

Thanks Deejayah - will have to do some hunting to get something similar in Aust.... I had it at 50mm (2") but then notice you all wish it was thicker. Will look into a 75mm (3") design.

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I finished modelling the 1100mm (43") design and converted that into a materials list and estimated the cost of the main, known components. This size does not easily work into standard sizes in Aust if you want to minimise cutting and wastage. So I recut the CAD files, re-estimated materials for a 1000mm (39") WFO and I believe this will be still plenty big enough, less wastage and simpler math and brick cutting to boot. I wont update the original specifications, as I think they are pretty solid if someone wants to do themselves a big WFO. Updated specs below:

1000mm (39") WFO Specifications

• Corner style design
• Igloo pompeii oven @ 1000mm (39") where the dome wall thickness is:
  • 115mm (4.5") - using a standard 75mm firebrick
  • 50mm (2.0") - CalSil blanket
  • 110mm (4.5") - Vermicrete (10:1)
  • 25mm (1.0") - Render
  • 0mm - Waterproofing sealant
  • Total wall width ~ 300mm (12.0")
  • Total dome width ~ 1600mm (63.0")
• Inner arch: 500mm (20.0") by 315mm (12.5") ID (63% of dome radius, round for std brick size) integrated with dome walls on a sailors course to maintain hemispherical top curve
• Outer arch:
  • 700mm (23.5") ID by 350mm (13.5") deep (1.5 bricks) providing a 90mm (3.5") reveal with a serpentine style construction
  • 200/250mm (8.0"/10.0") double wall stainless flu, 900mm (36") high with spark arrestor and rain cap
  • granite landing with ash chute
  • Thermal breaks: 50mm (2.0") stainless on landing as a plug to the ash chute, 10mm (3/8") recessed with ceramic rope on arch + sealant
  • Total oven depth ~ 1700mm (67.0")
• Stand:
  • Foundation: 2100x2100x150mm reinforced concrete (83.0"x83.0"x6.0")
  • Stand: 850mm (33.5") - 4.5 besser block course reinforced with rebar, rendered to match stenciled concrete
  • Hearth:
    • 2000x2000x120mm reinforced concrete with formed ash chute (79.0"x79.0"x4.5") and weep hole(s)
    • Builders plastic
    • 105mm - vermicrete (5:1) (4.0")
    • 50mm - CalSil board (2.0")
    • 75mm - firebrick (herringbone pattern) (3.0")
    • Total hearth height: 350mm (13.5")
    • Bolts concreted in for ash chute box
  • Total working surface height ~ 1200mm (47.0") (just above my elbow height)
• Final surround: polished concrete and/or granite tiles sloping away from oven

Now to plan arch and brick sizes/cuts ...

Thanks for the template JR - been years since I did some angles like that!

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Last thing for the evening - brick cuts required for a tapered inner arch. Once JR got my head around the angles and I googled some trigonometry - I started to build this template in FreeCAD.

Looks messy, but you only need to update 4 constraints against the keystone brick (inner and outer length, side length and mortar joint size - all the other bricks are then identical to this, with parallel sides). It will then leave you with a 'gap' above the bottom course of bricks to try and tie in nicely (guess). If the dimensions are too big, then it overlaps...

[JRPizza]

Great work! I think the 1 meter/39" size just works well for symmetry with standard brick and material sizes. It will be fun to watch your oven "grow" from the ground up and see how it follows your plans. I found the model helpful when I needed to make small changes and could quickly mock up different configurations to see how they would look and fit.
PS, I'm building a 4" thick door (hopefully work a little after the UW Husky football game) and will post some build pics. Did you say you were going to hire out the build of your door or are you going to fab one yourself?

[fnbroken]

Thanks John, 4" - that's deep! Will keep on eye on that one and see how much difference it makes.

Undecided on the build - I'm thinking if I can spec this all really well in CAD and have a number of stainless steel components to be made, I may be able to get a good price to have all the bits made (CNC) and shipped to me - I just assemble. I also have a welder and access to materials - so may go that option as well (although Ive never welded stainless and even my steel work leaves something to be desired lol - the last time I used it i blew holes in the metal and 6 weeks later it fell apart). The wood front and glass windows are also a great touch I want to explore.. so many options...

I like Russell's thin black steel door with the face cut into it - so you can see the flames licking behind it - I want one of those too...

[JRPizza]

I was checking out the "show us your door thread" and I think there are a few 4" doors, so mine won't be the thickest. I'm looking to use the door to hold heat after firing and between cooking, and make a lighter weight single handle door to use when the oven is in use.
I have not seen Russell's "light door", where did you see it?

[fnbroken]

My bad - it was Gulf's build...