portable oven

[david s]

Re: portable oven

David your awesome and patient.....

thats 5 parts cement to 1 part vermiculite, by volume isnt

Aahh, NO!
5 parts vermiculite to 1 part cement. I suggested 4:1 because I think you could probably do with the extra strength.
Just looked up osb and it appears surprisingly like what we call chipboard which is notorious for disintegrating when it gets wet. I thought you had settled on marine ply or steel as your supporting base.

[cobpaul]

Re: portable oven

It ended up being 4 parts vermiculite to 1 part cement, I put in some sand aswell. osb its like a cross between chipboard and ply, it is water resistant and does not swell. A cheaper substitute for ply, i think its called aspenite in the states.

The vermicrete is setting nicely and I think I could strike the form now, it feels very slightly soft to touch but it is dry, and it has the slightest amount of give when pressure is applied but it is concrete, unusual stuff alright.

How thick did you make your oven walls david?

What are your thoughts on purchasing a modular oven as opposed to bulding a dome in situe for a mobile oven?

[stonecutter]

Re: portable oven

It ended up being 4 parts vermiculite to 1 part cement, I put in some sand aswell. osb its like a cross between chipboard and ply, it is water resistant and does not swell. A cheaper substitute for ply, i think its called aspenite in the states.

I know it as osb...it's the common term, at least in New England and here in the southeast.... aspenite isn't really used as much. I can't comment on the board made in Ireland, but all the osb I know of here will swell up when wet (eventually), immediately on cut ends. It starts to de-laminate when exposed to uv and the elements after a few months too. It's used as sheathing here, and shouldn't be exposed to the elements for very long.

[cobpaul]

Re: portable oven

well stonecutter i made a shelter for the cat when it out the back garden from osb years ago in our old house it lasted 2+ years.

[david s]

Re: portable oven

i have no idea how your osb will stand up to weather and moisture, but it is sitting against wet vermicrete now, you decide. The 3" of vermicrete will take around three weeks to dry, in perfect drying weather (see attached doc)

I made my dome walls 2" thick for my mobile, likewise the floor.

I doubt whether you could find a precast kit small enough for your slab.

[stonecutter]

Re: portable oven

Best of luck with your build.

[david s]

Re: portable oven

My apologies I forgot to attach doc.

[cobpaul]

Re: portable oven

Ok I found a suplier who can custom make me a dome with 50mm thick walls, the overall measurements I have come up with are:

exterior diameter of dome: 660mm
fibre blanket insulation: 50mm
vermiculite cement: 75mm

My base is 910mm square, will these mesurements be sufficient for a oven that will hold a good enough heat for several hours??

Can I add the link of the supplier so that people can see what I am using or is that against forum rules???

Mikku I would love to be ready to go for the markets, but time and money are always against us + curing time lol. seriously im going as quick as I can. If I HAD to choose between a wooden or sand mould, I would choose sand

[david s]

Re: portable oven

Make your vermicrete layer thinner otherwise you won't have enough room for the outer shell or the vent at the front. With 50 mm blanket you don't need so much vermicrete anyhow.

[cobpaul]

Re: portable oven

so...what do you reckon 50mm vermicrete david? Also are there pros and cons if I incorperate a chimney stack?

[david s]

Re: portable oven

so...what do you reckon 50mm vermicrete david? Also are there pros and cons if I incorperate a chimney stack?

Yes, a flue is not mandatory, but you will get sick of the smoke in your face if you don't have one. You could always have one fabricated from sheet metal after you've finished covering the dome

[cobpaul]

Re: portable oven

forno bravo is based in the US I am not. Why not use the forum?? Its my first oven why not use precast?(I recall you suggesing that). I go at my own pace and schedule, I dont need to justify my time to anyone here, but out of manners and common courtesy to the people who have given their time replying to my posts and questions, I want them to know that their time is appreiciated and to know that I am still in the progress of the build.

Is that ok with you mikku?

[cobpaul]

Re: portable oven

mikku,mikku,mikku the only one that I have shown contempt for is you, and from what Ive seen Im not the only one who finds you irritating.

Ill invite you mikku NOT to post on my thread again.

[cobpaul]

Re: portable oven

You love the attention dont you!! What pics do you want to see and why so eager? Also how am I getting off easy, what power exactly do you think you have over me mikku? If I show you a pic will you go away?

[mikku]

Re: portable oven

You love the attention dont you!! What pics do you want to see and why so eager? Also how am I getting off easy, what power exactly do you think you have over me mikku? If I show you a pic will you go away?

Hey cobpaul!
The weather is beginning to turn cold, did you accomplish anything since May when we last conversed? There were a lot of people giving you advice --they are still waiting to see some results. Everyone asks for pictures when a build is in progress. It is a way to show that the person is not B.S.ing and doing nothing! It seemed like you were in such a rush--how about an update on your progress!