Rustic Primitive Materials

[cobblerdave]

Re: Rustic Primitive Materials

Yikes now wicking issues...

Seems like I have a better chance of flying to the moon on gossamer wings than making the simple humble oven that I had naively envisioned in the beginning.

New plan... I am going to set fire to Alan Scott's book and roast a marshmallow in the flame.

Thanks everyone I now realize this is not for me!!

Cheers, Annie

Gudday Annie
Not a peep out of you for a bit now. I don't think however you have given up on an oven. Exactly the opposite ....you have a stand made....a stack of firebrick purchased.... a stack of information as well. Recon your planning finished and your building now.
Well good on you....Go Girl.
If you read this and you hav'nt broke the link, how about a couple of pics when your finished...no comments or explainations required.... though I recon a simple Yippee!!! would be appropriate.

Regards Dave

[Tscarborough]

Re: Rustic Primitive Materials

Your first mistake is the Alan Scott book. God rest his soul, he has been the cause of more ovens being built that are inappropriate for their intended use than anyone in the world.

Burn the book.

Lay some poly down, put down a mortared base, then 4" of perlcrete, then build your oven per FB specs, if not design. It ain't rocket science unless you are building a rocket.

[Gulf]

Re: Rustic Primitive Materials

Please, Don't burn the book. Just put in the library until you finish your oven . A moisture barrier can be just moisture resistant paint, a piece of plastic, or a scrap piece of vynil floor covering placed between your support stand and the hearth.

[Gulf]

Re: Rustic Primitive Materials

Heat shouldn't be a problem below the Pcrete/Vcrete if it is a minimum of 4" thick. But, moisture wicking could be easily stopped by a moisture barrier between the supporting base and the slate.

[Laurentius]

Re: Rustic Primitive Materials

Hi Annie,

My concern was, slate absorb moisture, which can wick up from the base and if heated high enough would crack or break. P/Certe doesn't have the insulating properties of ceramic fiber board, so my question was, should the inches of p/crete be increase for added protection?

[Tscarborough]

Re: Rustic Primitive Materials

Not hot enough to worry about, I was answering it in the abstract.

[Tscarborough]

Re: Rustic Primitive Materials

Of all the stones you could use, I would assume slate to be the best able to take heat and not disintegrate because of it's makeup.

[Laurentius]

Re: Rustic Primitive Materials

Could you do 2 layers of slate and not lap the joints?

Would you recommend a thicker than normal layer of p/vcrete to protect the slate from the heat?

[Tscarborough]

Re: Rustic Primitive Materials

Could you do 2 layers of slate and not lap the joints?

[Tscarborough]

Re: Rustic Primitive Materials

Yes, you are right.

[Laurentius]

Re: Rustic Primitive Materials

You don't need much, a typical oven is only going to exert a dozen or so PSI on the slab, so it can be thin and uncomplicated, but you need an inflexible base for the oven itself. The slab will float on the insulation on the base, and any movement will be absorbed by it, not your oven.

Insulation on slab, right? Fingers faster than brain or the other way around?

[Tscarborough]

Re: Rustic Primitive Materials

You don't need much, a typical oven is only going to exert a dozen or so PSI on the slab, so it can be thin and uncomplicated, but you need an inflexible base for the oven itself. The slab will float on the insulation on the base, and any movement will be absorbed by it, not your oven.

[Tscarborough]

Re: Rustic Primitive Materials

Exactly. An appropriate thermal mass isolated from the environment and insulated to the maximum extent allowed by space and finance. Efficient and easy to use, as well as being extremely environmental friendly. Doing it right costs less than redoing it.

[cobblerdave]

Re: Rustic Primitive Materials

Gudday Annie
Sorry but I do have labour on the point of insulation. Sand is not an insulator. . Your little domestic oven has little mass so not much wood is needed to keep the temperature but let that fire go out and it cools rapidly.
With a wood fired like your planning to build has a larger mass but once that mass is heated And is insulated from its surounds it keeps its heat for days.
Days for you to cook with.
Dont insulate and you'll be shovelling in wood and heating up the stand and the surounds. Stop shovelling wood the heat will still be going into the stand and your oven will cool rapidly.
You might have heaps a wood avaliable but it has to be sourced, transported, cut and shovelled into your oven. That alone is a burden, better time is spent cooking.
Pearlite is cheap sourced from local garden suppliers/ hydroponics supppliers etc. Mix with cement at 1- 5 it will insulate you hearth. Mixed 10-1 will insulate the dome.
Again sorry for labouring on this point....but you'll spend as much effort and time building a poor oven as a good one so you may as well get insulation right the first time.

Regards Dave

[cobblerdave]

Re: Rustic Primitive Materials

Gdday Annie
I wouldn't put away you plans for a dome oven just yet. Yes there a plenty of Really impressive ovens with the brickwork fitting together like a puzzle and whilst you have got to admire the workmanship you can build a good dome oven a bit more simply.
I used 1/2 and 1/4 bricks to build my own oven and they were cut with a simple brick bulster and the fancy cuts with a inexpensive angle grinder and diamond blade. Yes you end up with some larger gapes in the brickwork but it still works the same.
Heres a simple plan for you to consider.
Run a level row of bricks around the top of your stand. Fill with concrete this will give you a 3 1/2 in top. add some scrap steel if you want for extra strenght.
Run another ring of bricks ( leave a couple of weap holes just in case) fill with "pearlcrete". Thats your base insulation taken care of.
Lay a layer of brick to form the hearth.
Build a brick arch for your entrance leaving the formwork in place for the moment.
Now a ring of brick in the shape of your oven mortar the edges not the bottoms (the dome needs to be able to expand separate to the hearth).
Now fill the space in the middle with wet sand or soil and shape it into the dome shape you need. A simple stick through the middle to check the height.
When your satisfied with the shape, cover with plastic or layers of wet newspaper to stop the morter from sticking to the soil.
Now brick it up with 1/2 bricks layer by layer till near the top you'll need some smaller say1/4 brick sizes. Yes use the poor mans mortar mix.
Leave to set for a couple of days, remove the entrance formwork and dig out your sand formwork. ( a good trick is to include some empty softdrink bottles in the sand form, less soil to dig out)
Of course you'll have to use that lovely cast door somewere in here and you have inslate the dome, a cover over that, entrance, chimney etc but first thing first.
Anyway hope something in here helps

Regards Dave