Stone oven.

[Grooveski]

Fancied building an oven for a while now but the only place I have permission to do it is a fair traipse away so it's been slow coming about.
Forgot to take any pics of it with the roof off but the gist is it's a flat stone bed then a 2½" gap then a 1½" oven base. There's a 2" gap between the back and the base to allow flow back and up. The sides and capstones are 1¼" and the oven size just under a foot square by just under two deep.

All dimensions are "ish".

There'll be a chimney at the back but not sure what size to make it. Was thinking 2-3". It'll just be a hole in the roof that can be covered with a flat stone to seal it for smoking duty.

The blackish rock on the right hand side isn't really doing anything, was just messing about feeling what it'd be like with some weight on the sides, felt good so I left it. Eventualy the plan is to weigh in the base of the sides with rocks, fill with pebbles(much like the existing ground)splodge it over with mud then turf it(probably with a patch of the bracken over-run field).

The turf skullcap is typical Scottie humour. I'd sealed the bigger gaps with skimmers and was in wide-eyed on-a-mission patter mode about how it'll all be turfed over so he lifted the turf from digging the pit, plonked it on top an announced "A turf oven!".
It just stayed in place too.

A chunk of it will be coming apart again and I've still to find the right capstones. They need to be curved on the underside so they're pushing out the sides a bit more, at the moment if one of the base stones split longitudinaly it'd be bad news. It should be free standing and the base replacable(I'm guessing).

The two oven base slabs are a snug fit. I pecked away at them with a lump of basalt.
They'll be better next time round but next time round will be it. Once it's turned into a mound it'll be a pain to tweak so if anyone has any suggestions....

....oh, and another question that pops to mind is can you do a charcoal burn in an oven like this so you have charcoal to use in the oven?
The rock is mica schist. It doesn't seem to fire-crack much, the base of the ring is slabs that have been there for years and they're fine.

 

[Toddy]

Nice one Josh

Funnily enough, I was buying pottery clay today to repair a clay oven. The place I bought it from supplies fire brick, kiln linings and cements, as well as heat treating metals
It's only just across the river from me, and the man I met there went to school with me, probably haven't seen him in over thirty years and here he all set up like that

He said that they have a cement that will dry out at ambient temperatures and fire to weatherproof just with firing it inside for use as an oven...........tempted, so tempted.

I do like your's though, be interesting to see how it does over time too.

cheers,
M

 

[Shewie]

That's pretty cool Josh, I thought I recognised that firepit

 

[Grooveski]

That's pretty cool Josh, I thought I recognised that firepit

Mind I said it was big for a reason? Always did fancy trying this and now it's lost a couple of places.

How hot do pottery kilns have to be Mary? Could you fire clay in this d'you think.

Was cursing myself for not having a good look at the ovens at the crannog. They were always on the go(and when they did get opened the goodies made me forget everything else ).

I'm guessing with the modern slabs you can bring them up to temperature quickly.
That's something else I'm still not sure of. I just made an ember base then moved it and some coals in, took a while for it all to warm up.
I think there'll always be the temptation to light a fire in the oven but think it'd be a bad move. When it goes it'll be while heating or cooling.

 

[Toddy]

There's firing and there's firing

We have pots in Scotland that are considered Bronze Age, yet these same pots are still being made today. They are called Barvas Ware and they are fired in a peat fire. When the pot is sufficiently 'cooked' it is covered inside and out with milk, and the lipids seal the porosity and make the pot suitable for holding liquids and the like.
An ordinary camp fire *can* reach temperatures of 600oC and that is sufficient to make this type of soft pot, but proper firing needs between 900oC and 1100oC for the clays to really turn to ceramics.
Basically, yes a bread oven will make pottery, but it will eventually crumble, might take a year or two to do it though

Happy to play
Clay's no bother, I just ask the workmen when they're digging up the roads around here All those fancy tiled closes in Glasgow were tiled using tiles made less than half a mile from here, we're sitting on beautiful puddle clay Embarasses HWMBLT no end when I stop and keek down the hole and ask can I have some of their mud
I think a blow pipe would increase the temperature a heck of a lot too.

They offered me a cement that will dry at ambient temperatures but will harden with any heating and become weatherproof
I really fancy one of those bread ovens in the garden. They're just made like tunnel shaped baskets and then covered in a clay/ straw mix and the cooking fires them. This cement would mean that it shouldn't crumble even if it gets wet.

The place I'm talking about will also do heat treatment of metals, and are set up for small stuff as well as large........ I can see a sudden increase in knifemaking

atb,
M

 

[Grooveski]

Given a strong easterly it'd have the capacity to cook itself to rubble. You could funnel in the breeze through with a rhodie leaf lean-tooD) and just run the main fire behind the front stone.

Thanks for the numbers. That's hotter than I was thinking of but like you say where there's a will....
May well take you up on a dollop or two of clay. Have never come across any out there.
Do you form bowls if you don't have a wheel?

Oven at the bottom of the garden sound's like a fine idea.
When you get your design down pat and do the group buy for material packs I'll take two.

 

[Toddy]

There are three ways that we can mould them easily. One is coiled, the next is just a thumb pot made from a ball of clay and dig your thumb in and widen it out carefully with your fingers, and the third is bat and stick. This one starts as a big lump but a curved stick is used inside and a bat beats the clay from the outside..........think those big middle eastern water jars, like small ali baba types.

I have an experimental archaeology book on clay ovens somewhere and I'm pretty sure Russ bought a book about them........think he was thinking about forging though

I'll have some of my local clay in the car on Saturday, I'll have a stop in visit to Loch Achray on my way up to Kenmore. Have a look if you get a chance and see what you think.

Definitely on the new clay at some point though

cheers,
Mary

 

[Chinkapin]

For those interested in building an earth oven there are page after page of earth ovens on youtube.

If I was going to build one, I think I would try to incorporate the so-called "rocket stove" principal into it.

If you are not familiar with the Winarisky (probably misspelled) rocket stove, just google it and you will find them from coffee can sized to home sized. They are wonderfully efficient.