32” cast oven in Warwickshire

[Badbobby]

For the casting, I followed the tried and tested home brew and the calcs we pretty much spot on. Hard to really gauge if I put in enough of the needles of fibres. As per all the advice, the lime is very nasty. I got a rash just picking it up from B&Q and getting it to my car! So it was very much a case of PPE (double gloved – washing up gloves under plastic builders gloves – no messing) to dry mix it in a tub in batches then add the water then the needles. Using a garden fork worked quite well.

I cast the dome first, then the gallery the next day. Removed a day later i think. Then a wet sheet over it for a while, which i dunked in water and re-applied daily.

[Badbobby]

Once that was done, I created my gallery. I did a one piece casting, for richer or poorer. Making the formwork took longer than expected. I put a “door” in the back to help remove sand from the dome area, which helped take away pressure. The outside was made from plastic floor protection sheet, which I had a lot of from my kitchen renovation. Doubled up, it was quite sturdy, didn’t stick and could be cut in a worst case. It came out pretty well.

I used the tip of an old paint pot with some cardboard packed around it. I also created some buttresses, but you can't see these on the photos below. Might show up in later posts.

For the dome, cut out a plastic membrane shape to minimize sand onto the brick floor. Then used bricks to pack it out as much as possible. I had loads of builders sand as i knew i would be needing it to build up the brick outer leaf and the rest of the bbq next to it. Pretty sure it took about 5 standard bags. Are they 25kg each? Covered with newspaper, just because. I think it might have helped avoid the sandcastle collapsing. Sprayed the sandcastle a lot to keep moist as it was really hot when i was doing it.

Again, borrowed the idea of the the wooden guide, by jigsawing the 40cm radius into some ply. Very useful tip, as was the putting in a 40cm high baton.

[Badbobby]

Left it for a week or so and then put some sand down to level and placed brick herringbone pattern. Cutting the triangles was a real pain as it was extremely hot in early June with full PPE on. More on it later, but I went 5 bricks wide at the front and time will tell if this is too wide. The bricks round the edge were a pain as the smaller ones just wanted to fall off the vermiculite layer! When it came to casting I kept spraying the sand with water and put temporary support bricks underneath to prop the slivers up.

Levelling the builders sand and ensuring that there were no lips was a pain. Better when wet. Kept redoing it as was not happy. In the end, i settled on any variations in height always running away so as not to catch the peel edge or the copper blow pipe for ember clearing. More useful tips accrued from the various other threads.

[Badbobby]

End of May UK bank holiday was a perfect chance to get going with it, so was able to pick up blocks, sand and cement from B&Q over the preceding week. So I got the block base up, pavers on and vermiculite base insulation layer sorted over the 3 day weekend. I used plastic lawn edging to make the form work with the left over decking that I’d ripped out to make space.

So far so good, until I realised that I had made the vermiculite layer 10:1 not 5:1 cement! So in the almost dark I tried to guestimate how much cement I put in originally and doubled it and chucked it in! I’d made the mix very wet (not on purpose) which meant I could stir in the additional cement easily.

[Badbobby]

Once that was done it was time to nail down the size. I got into the idea of building a pizza oven because I bought a smaller relatively portable wood fired one during lock down. We loved it but it was quite an intense process of turning the pizzas every 20secs and then reloading just the right about of extra little logs etc. So I have wanted to build a decent sized one for ages. However, I knew I was going to move house so I didn’t want to build one and leave it behind! Settled on just under 32”/80cm in the end as a target size.

Working back from the interior size was the first head scratcher for me as I had to ensure I was happy with setting out. Lots of excuses to procrastinate. In the end, I decided that I didn’t want to pour a slab and went with the idea of using 4x 600x600mm concrete pavers. Then had to check that I was happy that I would get enough clearance from that for the thickness of the dome, blanket, vermiculite layer and the entrance. I reasoned it was just about ok – 80cm max interior, then 5-10cm cast thickness and similar again for blanket and vermiculite on each side.

Besides, I could freestyle as I went a long (part of the attraction for home brew vs expensive pre-cast kit). Meanwhile, I placed my order for bricks, refractory cement (didn’t use in the oven, but plan to use for my bbq next to it), clay and first batch of vermiculite. I was able to collect from Kiln Linings as I was kind of up that way with work. Massively over ordered bricks to hit the minimum order/fear of under ordering and they just fit in the back of my E63 wagon and without overloading the springs! Drove carefully home though…

[Badbobby]

Like a lot of people, I came across this forum via links to threads that steered us away from the nonsense vermiculite yoga ball methods. So this forum has done a great service in this regard as I’m not the first and hopefully not the last!

I had though already been looking at a “proper” way of building an oven using a kit from one of the UK based suppliers. In the end, I like projects and, once I discovered that I could cast my own oven in my own time, I think I was not going go back. Part of my kit reticence was that they were all slightly different in approach, some things were or weren’t included. So decision was made to wing it.

First up, I was lucky to have what I felt was a purpose built area in which to build this. The photos show an L shaped brick structure that originally had a dwarf wall of bricks and decking on top to act as seating around a table. So I took out the decking and bricks, many of which I’ve reused (not as easy as I had hoped) to save a) taking them to the tip and b) I feel it’s the right thing to do re wastage/save the planet etc.

[SableSprings]

Welcome to the forum family...and congratulations on starting your journey learning to use your oven's unique cooking capabilities!

[Badbobby]

I’ll start my write up, mainly retrospective, to cover my build. Mainly to help others to follow and to allow wiser minds than mine to chip in and correct any rubbish that I write

I’m currently at the insulation drying out phase hence have some time to take a step back and document it all.