Casting Homebrew Oven - Build Log

[aaronpizza]

I've started building my oven!

I've nagged many people on here for help - so I will document what I've done, I hope it will help others!

Please DO point out any improvements/errors and suggest any ideas - it will be gratefully received.

Pictures / details to follow.

[aaronpizza]

So I’ve made a start…
First, I marked out where I wanted it to go and got the sign off from my wife


I dug it out, lucky for me, my soil and subsoil is very sturdy, I went down about 40cm, backfilled with hardcore and compressed this.
Then I added about 15cm of concrete (4:1 of Ballast and cement), with some 8mm steel rebar grid to keep it stiff/reduce cracking. I mixed it all by hand in a wheelbarrow.


I went for the solid concrete blocks around (415x215x100) with a mortar (5:1 of builders sand and mortar cement), mixing it in medium batches.
I am a horrendous bricklayer so I did the first layer, got it very true/level and left this overnight.

The following day I build the rest of the wall, excluding the front end.

I stopped at this point as I need my lintel to bridge the front end (see drawing for final look)


Next, I need to make the top countertop, this will be ~15cm of concrete, which will slightly overhang the base at the back and a curve at the front.

Any questions please do ask!

Would you like people's thoughts on the concrete top, how thick would you suggest?
The span between the blocks is 90cm (internal).
My current thinking is 15cm, but I think that is overkill, given the weight will be on the outside (nearly directly above the wall).

[UtahBeehiver]

Based on being a small diameter cast oven, 4" should be fine or 10.16 cm of concrete with rebar (not v or pcrete)

[aaronpizza]

Thanks yet again UtahBeehiver .

I have 2 questions if you wouldn't mind pointing me in the right direction ?

I've been trying to find an ideal hemisphere shape, which the internal wall should be, however, I can't seem to find this?
Some designs have a straight wall up, then a very shallow dome top.
Others are perfect semi-circles (which I understand isn't ideal for cooking the top of the pizza).

Also after I have my homebrew cast etc, is this when I should leave it to dry, then slowly over days fire it up increasing the temp to cure/bake/dry it, then add insulation and other layers after this has been full fired?
Or should I finish all layers, insulation etc, then do the fire/curing process?

Answers/points in the right direction would be amazing

[david s]

The hemisphere is the standard form that works well for both pizza and baking and roasting. Some dedicated pizza ovens have a low dome so the crown of the dome is closer to the pizza resulting in faster cooking. This does introduce a less stable structure and leaves little height at the perimeter making bread baking difficult.

The easiest way to make a form is to build a sand castle covered in wet newspaper, in situ. When the casting has been done remove the sand.
Firing an uninsulated oven is asking for trouble. (There is a video here somewhere showing an uninsulated flue tile exploding from the heat of a few sheets of paper). So it's better to fire slowly after the dome has been insulated and before outer render coat IMO.

[aaronpizza]

The hemisphere is the standard form that works well for both pizza and baking and roasting. Some dedicated pizza ovens have a low dome so the crown of the dome is closer to the pizza resulting in faster cooking. This does introduce a less stable structure and leaves little height at the perimeter making bread baking difficult.

The easiest way to make a form is to build a sand castle covered in wet newspaper, in situ. When the casting has been done remove the sand.
Firing an uninsulated oven is asking for trouble. (There is a video here somewhere showing an uninsulated flue tile exploding from the heat of a few sheets of paper). So it's better to fire slowly after the dome has been insulated and before outer render coat IMO.

Thank you, yes I saw the video about the uninsulated clay pipe - was intresting, I was confirming as I've seen a few people fire their oven without insulation :O

For the hemisphere, I was thinking a internal diameter of 83cm, what would be the ideal height - or have you any examples of builds which work well ?

Yes I am planning on doing the sand newspaper cast.

[david s]

The internal height of an 83cm diameter would be 41.5cm. If you want a low dome search for "Neopolitan ovens". If casting you can have it both ways by having vertical walls for say 10-15cm then a large radius dome to keep the top of the dome pretty low.

[aaronpizza]

The internal height of an 83cm diamanté's would be 41.5cm. If you want a low dome search for "Neopolitan ovens". If casting you can have it both ways by having vertical walls for say 10-15cm then a large radius dome to keep the top of the dome pretty low.

Thanks David S, I think I will go with the stright walls, then the large radius top as you mentioned - I'll do some more reasearch on the Neoplitan ovens first

[Poochdog12]

Always great to read guys,,, I’m wandering about my oven on a trailer now. It’s going to be mainly for pizza. Would it be best to build it with straight walls and shallow dome, or keep it as a hemisphere for strength?? The having both you talk about Dave is interesting. Aarronpizza is yours on a trailer or fixed at home.

[aaronpizza]

Always great to read guys,,, I’m wandering about my oven on a trailer now. It’s going to be mainly for pizza. Would it be best to build it with straight walls and shallow dome, or keep it as a hemisphere for strength?? The having both you talk about Dave is interesting. Aarronpizza is yours on a trailer or fixed at home.

Hi Poochdog12,

Note I am a total newbie - Just absorbing this forum as we speak!

A hemisphere is going to be stronger 100% and thus will keep the weight down too.

The biggest risk you have is the vibrations from the road and it twisting and cracking while moving it all the time...
I won't comment on how to fix this as I'm not the best person too - it's going to be a challenge for sure!
Have a mooch around I've seen a few trailer ones on here - although rare.

My build is 100% never going to move, currently, as you see in the photos, it's total raw component weight is about, 500KG.
Foundation, bricks, and mortar.
I expect the finished weight to be around 1000KG, I've yet to calculate it properly!

[Poochdog12]

hey aaronpizza,

thankyou for your reply mate ,i think your right ill stick to the hemisphere, im going to have a 4" steel ring welded around the oven and then cable strapped and turnbuckled over the vermicrete layer of the dome,..... so big fingers crossed it doesnt move..

yours is going to be awesome, and this forum is a wealth of great advice. i built one a few years ago just from youtube. wish id known about this back then. iv learnt loads more since then.

where are you up to your build now??

[aaronpizza]

@Poochdo12, the photos above are where I am at - I'm struggling to get hold of any materials at the moment!

I've made a large order which contains most things, so soon I should make some progress!

When you start yours - keep us posted!

Yeah I almost went the youtube route, then this forum saved me haha

[aaronpizza]

Latest update -

I have *everything* ordered.

Until I notice soemthing else haha

So I ordered 50 bricks, which was about £130 delivered, I got many quotes from everywhere ranging from this price to over £9 a brick!

I also ordered some ceramic blanket today, sadly after ordering they told me they were out of stock, so they upgraded it to some better stuff for free

I have some photos waiting to upload of the 4inches of insinuation and sand on top for leveling.

I finally settled with 900mm inner diameter.

Fire bricks I went to 76mm thickness.

Just a little brain dump

[R3CALL]

Hi Aaronpizza have been following you and munsters thread. Where did you source your fire bricks as I'm just trying to work out what I should go for. Debating if I should go clay bricks or storage heater bricks which work out to 230mm X 190mm X 50mm for £5 qty 2.

[aaronpizza]

Hi Aaronpizza have been following you and munsters thread. Where did you source your fire bricks as I'm just trying to work out what I should go for. Debating if I should go clay bricks or storage heater bricks which work out to 230mm X 190mm X 50mm for £5 qty 2.

Hey,

Sorry I've been rubbish at updating as I have to shrink all my photos before posting and I've started laying a patio!

I've ordered my bricks and blanket from https://www.vitcas.com/prd/cty/firebricks
or for a slightly cheaper price have a look on ebay it's about £2 per brick plus £30 P+P.

I have no experience but I would only use firebricks using the alternative seems like cutting corners, I think the base your food touches should be top priority