cobblerdaves build

[cobblerdave]

hi all thought I had better post some of the build to date.
Hope this helps others in Brisbane and Aust to build a WFO.
Forno Bravo Plans.... GREAT!!! read them and read them again there is so much in there its amazing. I have mine in a folder broken into sections ie foundation blockwork etc. Its now a bit dog eared and cement stained but I still refer to it as I go.
The other is a small mag you can get in most newsagents by Earth Garden called Backyard Ovens not much on the detail but covers everything from cob to brick ovens to commercial builds. Its a great read and I have pulled it out many a time when something has not gone to plan and I need my spirits raised. Usually works makes me hungry and I whip up a quick dough and make a pizza in the kitchen stove.
Well it all starts with a hole in the ground my block is sloping so one side of the slab is over 300mmm thick and the top 120mm. We have sandy soil here so the edges of the slab are thicker on the edges than the middle ,cup shape so it floats on the ground. Mesh re enforces so it doesn't crack. If you have clay soil or a mixture it woul be best to consider some deaper foundations at the edges.Best tool invented its the battery drill and chip board screws you just line up your formwork and drill better than nailing everytime, you hammer in a nail you run the risk of knocking something else out of plumb

[cobblerdave]

Re: cobblerdaves build


blockwork for the stand
Stack up blocks like lego and core fill the spaces with concrete !!! just love those plans



formwork for floor
Used me fovourite tool again battery drill and screws. all the wood salvage apart from some 35x75 mm pine from the bunnings cheapy bin. Used the remains of an old chipboard cupboard for the base taped the edge so the concrete could not seap in. worked well came away easily and didnt stick to the slab when formwork was removed



steel work in place

Had a collection of bricks on hand so I ran a layer around the edge Looks good and no formwork requied for the slab edge. dropped bent steel into the every secound unfilled hole in the blockwork to the floor in the slab. Looks like I'm comitted now recon I ll need a bobcat to knock this thing down. Child bride is horrified be the size and the time taken thus far and still no pizza.

[cobblerdave]

Re: cobblerdaves build

Hearth insulation


for the hearth insulation I used 50 mm (2 in) Hebel block mainly because I was given some free again used a layer of 50mm payers at the edge of the slab instead of building formwork should look good at the end I hope.

Hearth itself

This was the hardest point of the build which brick. I had already found out many ovens had been built of white brick commons but had found a supplier of 29 per cent cilica brick locally. Which way to go: full fire brick hearth and dome , fire brick hearth white commons for the dome? The fire brick were $3.30 ea up to 200 bricks required that would be a major expence were to date I had been lucky to find most of what was required for free. I went up to Dimore one afternoon to check out bricks in general . I was tempted by a stack of white commons .50c each secounds yes, a bargain definitly.
Checked out a stack of fire bricks wow you can tell the difference Heavier smoother and perfectly formed. Hang the expence I brought 75 to start it will be a fire brick oven. I brought another 100 later on and the final build for the oven was 162 but I tell you I took the time for ever cut. Finally thought I was onto the major part of the build the Oven!

[dmun]

Re: cobblerdaves build

The fire brick were $3.30 ea

When I die I want to come back as an Australian fire brick vendor.

[Johnny the oven man]

Re: cobblerdaves build

When I die I want to come back as an Australian fire brick vendor.

You will go broke. They are almost totally imported, and shipping costs kill any profits.

[cobblerdave]

Re: cobblerdaves build

Your right its a bit of an expence Child bride only saw the bill for the first 75 bricks and not the secound 100. So....to date I'm of the hook......

[cobblerdave]

Re: the Dreaded dome

Thought I'd better put some more down

This part was for me the scary part bricklaying has never been my strongest skill. Yes I have built a few brick BBQs over the years but I've always gone for the rustic look or if too bad, Bag render the lot.
Hearth turned out well so I set about on building the dome entrance, planned a lovely arch but this was not to be. Set out some bricks on a large piece of ply sort my angles, made a guide to hold the things up till dryed. Attempt one... looked like the dogs breakfast. The cement didn't have time to dry and I pulled it down. Secound go looked.. well good enough.. left it for a week to dry.. and cracked it removing the form.
Used the "easy out" in the plans and used angle iron and made the entrance square. Bit Disapointed but consoled myself with the fact I had gained the max size in entrance way for larger baking trays
Stopped using Fire bricks past the entrance to save on bricks expensive beggers and I am very pleased with the rustic look.
My failed attempt at the dome entance arch has now influenced my plans
Build a dome guide out of ply to support the stucture. and went for the higher dome hieght.

[cobblerdave]

Re: cobblerdaves build

Back again..... still raining here, wettest September on record and still coming down into Oct. Ovens soaked and covered with a tarp awaiting a dry period so I can seal the render
Dome construction..... Was not as hard as I imagined it to be I definitly didn't need to rely on the dome guide I had made till the last 3 chains went in



Keystone... just like the plans I got to that last opening and pealed down a brick to close that final hole felt a last all the work was worth it. pretty proud of myself as well



Final coat of fire cement was then layer on to add a little more thermal mass (remember I only had 29 percent silica brick) I had gone from the proud stage to the really chuffed one. Hey this thing was really looking like the real deal



Allowing the oven to dry over the week me and the child bride were inspecting the finished product on Fri night after work. How are you going to get all that ply out she asked. Easy we burn it out! When? Why not now?
Half a crumped newspaper and a match and it was away!! Boy was it away That ply went up like a bomb and in no time flat we had a roaring ruddy great fire rageing in the oven. A ruddy great big scary fire and I started to panic would the oven Hold up? Would the heat be to much at this early stage?
It finally ran out and in the glow of the bed of coals you could see the white brick and the pattern as it went up to the keystone. Worked like a charm.
We made up a quick dough cut some wood and feed the fire will the dough rose and in the end had our first Pizza.



Now building the dome quide out of ply worked for this time but if I built another I would not do it again to many thing could go wrong burning it out was diffinitly a bigger fire than I first though it would be.

[cobblerdave]

Re: cobblerdaves build

Better finish this off
Chimney since I change plans mid stream I was left sorta not knowning what I would do for a chimney. original plans were to have a stainless steel one but since I ended up with a large oblong opening I continued along these lines and have a wide low oblong "60" style ... cool. (I Hope). height to be determined by the height of the dome after insulation.
Insulation Bit. the bullet again and went Hi Tec again and got me some ceramic thermal insulation. Great stuff easy to work with went on like a charm and I ended up with 2''or 50mm over the dome bar the last 200mm whwere it only 1 inch. Next was to be a layer of perlite cement but this was to be a nightmare. the stuffs not able to be trowelled ended up building a cage to contain the blessed stuff. To top it off it rained no tarp no 2 son lent it to someone. A frantic race started to rip the cage off remove the pertite layer before it melted into the ceramic lot and finally cover the ceramic layer in a tape layer of plastic garbage bags. Bit of a mess to clear away Don't let my experience turn you of the pertite I just had bad luck. Did a bit of investication turns out rockwool insulation is formed at 1400 C that I had. A bag left in the roof, low on funds, what the heck a few inches of high tec insulation should protect from the highest heat. Added a coupla layers compressed it with the remains of the wire that was for the perlite recon the ceramic layer would handle the hottest heat of the brick dome. Works? seems to... months later the dome always remains cool to the touch.

[cobblerdave]

Re: cobblerdaves build


The pic shows the state of play today not all finished but a lot more added.
Rain was a major stubbling point spend ages with the dome soaking wet anable to use it as a small fire would make it steam so after it dryed out enough i sealed it. as you can see not all the works finished. But its getting there rain permitting.
Cooks well? YOU BET makes a great pizza and as I gain experience great for slow roasing as well. Well worth all the effort and still great fun Thanks Forno for the Plans Thanks all you guys and girls posting on the forum your a wealth of knowledge.

Regards ........DAVE

[cobblerdave]

Re: cobblerdaves build

Hi all


state of play thus far still suffering from intermittent damp. As you can see from the photos the ugly piece of tin and the even uglier piece of blue tarp have solved the problem but a prettier more perminent solution must be found.
Problem stems from the hearth continuing to the edge of the slab and the entrance is 1/2 brick back. Any rain doesnt flow into the oven but is soaked up by the brick and of course is wicked in by the hearth insulatution.
I concidered cutting the brick back to the entrance level but its good to have one level right back into the oven. That left me with the option of rebuilding the entrance itself. Wow that would involve knocking down quite a lot a major job at this stage. And it would give me quite a tunnel to work the oven through. I decided ... Do noting rash... wait...Watch the forum and do something in the dry months of winter.
I finally came across few comments on a few thread on entrance depth and finally one with some measurement... great mine is'nt that bad so the plan is to build an extention to the entrance...Thanks Oscar... and its to be a arch

Regards Dave

[OscarA]

Re: cobblerdaves build

Great job on the arch Dave I'm glad my build helped you decide on the arch and hopefully your rain issues are now a thing of the past.

[Himzo]

Re: cobblerdaves build

Hi Dave,

Just curious, how is the hebel as an insulator? The reason I ask is that I am having my house rebuild and it's being clad in Hebel, so plenty of offcuts around which I may be able to use.

Himzo.

[cobblerdave]

Re: cobblerdaves build

Dear Himzo
How have I found Hebel as a insulator.....well its worked for me... but the tried and proven is the old pealite it seems.
Didn't work for me at the time the only supply of pearlite i could find was expensive small bags at Bunnings /garden supplies. I have since found 100 ltr bags are available at hydroponics suppliers at about $35 a bag.( A ltr is aprox 10cm2 by the way)
At the time funds were low and I had already heard it was a good (affordable) method of hearth insulation in other oven types so I went agaisnt the tried and proven in the instructions.... its worked for me the ovens not crumbled into the insulation layer after 20 good firings.
If its not that eco stuff , the stuff with the strofoam layer... plastic you don't want that and its what you have ......well why not.. its up to you what you decied but there are a lot of oven builders in SA put a thread out asking on insulation and your sure to get some great local knowledge

hope this helps
regards
cobblerdave

[cobblerdave]

Re: cobblerdaves build

[QUOTE=OscarA I'm glad my build helped you decide on the arch

THANKS AGAIN!!!!

DAVE