First (and only) build in Newbury

[Ego Pizza]

So I have been going about 3 weeks now and have just completed the top slab.  All fairly straightforward - I guess the specialist stuff starts now.

My build is what looks to be a a fairly standard 1050mm internal diameter Pompeii oven




Prepared formwork for base slab





First layer of hollow blocks.  I found hollw breeze blocks quite difficult to find, but got 400x215x215 ones from Travis Perkins in the end.  I went for 4 across 4.5 deep, which gives me 1760x1980mm size for the hearth - about right for my dome with a little to spare.






Full 4 courses laid.  I also added a central half wall for extra support.  The only slight mistake I made was laying the blocks too tight on the bottom layer.  This meant i couldn't line up the subsequent layers well, so had to dismantle and start again.  5mm gaps worked much better

More to follow

Sam

[Ego Pizza]

More progress...






Formwork for top slab under construction.  I changed my plan as i was going to put a top layer of blocks across the front, but thought it would be too low an arch - i just used 2 angle irons across the top of the 4th layer in the end.  Probably not necessary, but I had them anyway.  Not shown in the pictures, but i added quite a lot of steel - about 10 each way spaced at 150mm.




Managed to pour the top slab yesterday. Hard work mixing and pouring the concrete from a bucket. I reckon it was about 20 barrow loads

Now onto the more interesting bit

Sam

[oblertone]

Nice tidy build, well done. What are you using for the dome ?

[Ego Pizza]

Thanks

I'm planning on a 50 mm insulating base then standard 230 x 114 x 76 firebricks from kilnlinings for the cooking surface and dome

Questions i'd appreciate some advice on:

I've never worked with calcium silicate board  - is it firm enough to support the dome?  Also kilnliinings are now selling board call 'body soluble' - does anyone know what this is, and is it effectively the same as cal sil?

Would you recommend the cooking surface bricks extending under the dome, or the soldier course outside?  

Finally whats the benefit of homebrew mortar over a ready made refactory mortar?


Sam

[oblertone]

Some answers:

'Body soluble' means the fibres the substance gives off are capable of being dissolved by your body should you ingest some, unlike some of the older insulating material which had fibres that wouldn't dissolve, for example Asbestos.

The cooking surface bricks should in theory be contained by the dome bricks, if you do build like this then a bit of corrugated cardboard between the floor bricks and dome around the perimeter will burn out to leave a uniform expansion gap. Doing it the other way I.e. Building your dome on the cooking floor can be done but you can leach heat under your dome*.

The main benefit of homebrew over refractory mortar is that it is perfectly suited to the job in hand, and considerably cheaper. Your WFO will reach 550c but refractory mortar will stand temps of over 1500c as you might find in a kiln; it's just not necessary.

* I built my dome like this and it works just fine.

[downunderdave]

Jun 22, 2016 11:39:15 GMT Ego Pizza said:

Thanks

I'm planning on a 50 mm insulating base then standard 230 x 114 x 76 firebricks from kilnlinings for the cooking surface and dome

Would you recommend the cooking surface bricks extending under the dome, or the soldier course outside?  

Finally whats the benefit of homebrew mortar over a ready made refactory mortar?


Sam

There are some advantages and disadvantages for each way, just make sure that the whole oven has insulation under it.
Dome on top of floor: saves some time because you don't have to be so accurate cutting the perimeter of the floor bricks. Downside is that removing a floor brick that's under the dome, down the track, is nigh on impossible. Not really a problem as any failures are going to occur in floor bricks in the centre of the floor.
Floor inside dome: you won't have a horizontal joint that gets worn away by the metal peel, provided you stand the first course of the dome vertical (soldiers). Disadvantage is that the perimeter needs to be cut really accurately to make sure it's a perfect circle and you will be left with the odd really small floor brick in some places.

[Ego Pizza]

Thanks for the replies - very helpful

I'm going to lay the floor inside the soldiers, but perhaps get some of the bigger bricks from kiln linings.... and will go with the homebrew 



Sam

[Ego Pizza]

Been building slowly but steadily

I laid my cal sil board on the slab and then skimmed a 25mm layer of castable over it.  Basically I copied the approach from the Melbourne firebrick company.  Worked really well as it gave me a nice flat surface to lay the hearth on







Hearth laid and being cleaned up by slave labour.  Cutting the hearth to a tidy circle was a real pain and time consuming as I had decided to lay the soldiers outside the hearth and wanted a good fit. I also found laying the bricks nice and flat quite tricky - you get one slightly out and it sets all the others out as well.  Anyway quite pleased with the final result











I laid full bricks on end for the soldiers. To fix the IT I used the piece of ply I had used as a template for the hearth bricks - I simply laid this inside the soldiers and fixed the IT to it.  No need to drill into the hearth and I am hoping it will protect the hearth during the dome build. 



More to come....

[slen916]

looking really good ego,i took alot of ideas from the melbourne brick company oven and it works brilliant.

[Ego Pizza]

Inner arch completed  - worked well apart from I ended up with an even number of bricks in the arch so made the key stone a bit more fiddly

[Ego Pizza]

Dome almost complete - for the last 2 layers I cut each brick individually based on a cardboard template. Not sure if this was necessary but the gaps would have been quite big with just standard bricks.

I used the IT for the 2nd last layer - the bricks seemed to hold in place quite well if left for 5-10 mins before taking the IT off.  I also propped them with a bit of wood.







For the last complete layer I made a plywood support


Just cutting the




I've managed to build through the cold weather by covering the dome with a polythene sheet and putting a small blow heater inside


Just cutting the key stone and the dome will be done

[Ego Pizza]

Slen - I agree the Melbourne plans are really good - for anyone who hasn't seen them here is the link

www.melbournefirebricks.com.au/wood-fired-pizza-ovens/

[Ego Pizza]

I now need to build my outer arch and design and fit the chimney - not sure of the best way forward - and would welcome side advice on the chimney


What size of chimney should I go for and should I use single wall or twin wall flue? 8 inch seems to be a fairly standard size!

The gap between my 2 arches will only be about 110mm (4 1/2 inches).  Do I need to make this wider if I am going to use a wider chimney.

Where is a good place to buy chimneys

I was thinking of simply filling the gap between the two arches with castable (which I have left over).  I could build a plywood form and cast the castable in place.  Does anyone see any problems with this.


Any advice greatly appreciated


Sam

[downunderdave]

Yes, casting the flue gallery is far easier than building it in brick. It allows you to easily get a good shape. Creating a form like an inverted funnel allows a better flow of smoke. Make sure the castable is not too tight around the flue pipe or it can crack your casting when it expands.
An 8" diam flue pipe is the correct size for your 1 m internal diam oven.

[Ego Pizza]

Thanks Dave

Would you recommend casting the chimney base in place, or casting it separately?

Sam