New UK Oven

[PeterW]

Well its started !!

After leaving the base to settle (!) for about 5 months, I've been finishing the insulated hearth and rendering the walls of the base today.

Due to space, I'm looking at about a 31" hearth on a corner install. The final design isn't finished, but SWMBO wants a 'brick looking oven' rather than an igloo, so it will probably end up clad in a brick skin ( so it will look like a brick igloo instead.... )

Walls are all 4" thermalite blocks, on a 8" plinth. The hearth is 4" of reinforced concrete with rebar set into the walls, and 3" of vermiculite concrete. I've no idea what happened, but the vermicrete didn't want to hold together, so today its had a dry sand and cement binder layer with 4" thermalite (AAC) blocks over the top.

Bricks for the dome are coming from Martin (Thanks ! ) and his recent eBay win, and I'll be cracking on next weekend as long as the weather holds !

Oddly enough, both my neighbours have WFO's - one is a sort of adobe style, the other is a precast from Purimanchos. Wonder if we'll get some oven-envy going on !!

I have to say, this forum keeps me going - the help and advice is always available !

Cheers

Peter

[Carl]

Good start! I didn't use the thermalite for anything structural, so it'll be interesting to see how you get on. You'll need to protect the thermalite from water, because it soaks water up like a sponge, and won't do any insulating if it's wet. I presume the brick skin will keep most of the rain off.

I've not used it, but from reading other posts here I've heard it can take the vermicucrete a while to harden?

[gjbingham]

Welcome,
Great start on the oven. I look forward to watching your build. I'M not familiar with your materials so I can't have any fun second guessing you

[PeterW]

Had a couple of busy days - got the base rendered yesterday, and got my 9 year old moving all the wood into the store under the base today ! Murphys law dictated it was me that knocked a chunk out if the new render of course !!

The dry mix sand/cement (5:1) that was used under the thermalite (AAC) layer and to dry grout it has now gone off, and the whole lot is rock solid.

I've dry laid the base and stem walls today to get an idea of the size etc. Due to the base size, its looking like a 29" dome, which will give me something like a 16.5" dome height and a 10.5" door height - does that seem right...?

Anyway - photos at the bottom

Cheers

Peter

[biondoli]

Due to the base size, its looking like a 29" dome, which will give me 
something like a 16.5" dome height and a 10.5" door height - 
does that seem right...?

Peter if I understand well your design, the height of the dome is 16.5 and you start with full standing soldiers (9"), if so then you have only 7.5" to close the dome...why don't you start with flat half brick?

[gjbingham]

Seems like a good question biondoli. Talk about an extreme curve of the dome! The radius of a 29 inch dome is 14.5 inches dome height. That would give you a perfect half-sphere. Higher than that is less efficient. If you stand the soldier course on end, you're already at 9 inches!

I'd consider even starting with 1/4 bricks for the soldier course. The door height should be 60 -65% of the dome height. I'll let you do the math.

[PeterW]

Well I've been busy...

Took the advice (sort of ) and changed the design slightly. I've cut the hearth bricks to a round, and stood the soldier course round the outside. Last weekend saw the soldiers plus the first cant course, Wednesday saw me get another couple of courses up, and today saw me put 2 more in and close the dome !!!

Its a bit dark for photos now, but theres one in my gallery showing the first couple and the arch.

I had gone down the route of casting an arch with Chamotte and Fire clay, but after a day of drying, I had more cracks than arch, so I ripped it down and did it properly !! The real shame is that a cut brick arch took me about 45 minutes to complete, against a couple of hours on the cast one !

On to vermicrete skin tomorrow, and building the outer brick dome ! Its getting exciting now !

Cheers

Peter

[Frances]

Originally Posted by PeterW

Its getting exciting now !

Building the dome wasn't exciting enough for you? What does it take?!

You have been busy, that was very fast! I look forward to seeing the photos...

[PeterW]

OK

Got the camera out this morning, and took a few photos. The dome was built with a mortar of sand, cement, lime and fireclay. I've used a pre-bagged sand cement mix (for sheer laziness... ) and its worked pretty good. I've got plenty of fireclay left over, so any UK builders give me a shout !! The dome has been 'freeform', as the mortar has been pretty good at holding the brick, even on pretty steep inclines. In some cases, I've held the brick up from below with another brick or piece of wood, just until the mortar has grabbed hold.

I've not done much today, just fitted the thermocouple controller and wired it up, and painted the base with a couple of coats of masonry paint.

There is a 50w bulb in at the moment providing some warmth to start the drying out - I'll leave it this week and then it will be at least early next before I can do much more. Hopefully, that will give it plenty of time to harden off before I start firing with avengance !!

The last photo shows what happens when you try and mix fireclay based cement with a mud mixer and an SDS drill... Yes, I've wrapped the steel blades round the shaft !! That stuff is sticky !!

Pete

[gjbingham]

Nice work! What height did the dome end up being?

That's going to be tight quarters for cooking, but I've no doubt that it will cook great pizza. Congrats on finishing the dome!