newbie need advise for my oven

[david s]

Re: newbie need advise for my oven

Outside is better IMO. Outside makes it a crossdraft, inside makes it an updraft. Crossdraft produces more even heating and more efficient. Check out Lburou's build for cross draft. If you put it inside the oven you will need a damper on the flue.This configuration does not have an entry to hav to work past, check out Brickie in Oz's build.

[gonzo420]

Re: newbie need advise for my oven

Hi again,
A quick question but I'm re-watching demos of constructing a barrel shape oven, and I noticed all of them place the chimney inside the oven rather than outside like the pompeii shape. Which way should I do it? I was gonna do it outside..

[david s]

Re: newbie need advise for my oven

If you halve the bricks you should end up with a more spherical form to render over the final coat (presuming you are intending an igloo rather than a dog house). Love to see some photos.

[gonzo420]

Re: newbie need advise for my oven

They will conform to the spherical surface better if you halve them.

If they conform is that a good thing or bad? Do you mean it will create more mess to take heat into and by that make the oven not efficient? Sorry if my understanding is poor

I bought the ceramic blankets today. I will cover the dome with the blankets and then maybe cut 'em to half and extra insulate the dome

With the ceramic blankets I think I'm good to go!

Bought the refractory concrete and the rendering mix too! Can't wait to get my hands dirty

[gonzo420]

Re: newbie need advise for my oven

forklift that puppy off and on to a trailer and happily take it to its perminent home.....
Just saying ......
Regards dave

If I can use a forklift then I'd build a proper one to begin with.

My design is pretty simple. The heaviest part of my oven will be the dome which will be separate from the cooking floor. It will take a few men to lift up and put on a trailer.

[david s]

Re: newbie need advise for my oven

The bricks are 32x12 and 80mm thick, they are the same size as the fire bricks.
If you say 100mm thick then I shouldn't cut them and I'll use them 'as is' on top of the dome. I guess breaking them apart and do the homebrew mix will make the insulation better but wouldn't it be fine just like this?

I placed a firebrick on the stove this morning with the insulating one on top of it for more than an hour. The temp on top of the insulating brick was 30 degrees. on top of the fire brick was 160 and where the insulating brick touches the fire brick it was 77 degrees.


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They will conform to the spherical surface better if you halve them.

[cobblerdave]

Re: newbie need advise for my oven

Gudday
This is getting to be an awfull amount of effort and good materials going into an oven that's to be pulled apart in a years time and hopefully be able to save the materials . If it was me I would consider two options
One ....buy myself a pizza stone, save the materials and research and dream of next year
Two..... Build an E shaped dry stacked block stand. Bolt together a top from layers of 12 mm compressed concrete and build me a proper ridge didge 25inch oven on that with all the bells and whistles and have 12 months to play. Then ....comes the time, forklift that puppy off and on to a trailer and happily take it to its perminent home.....
Just saying ......
Regards dave

[gonzo420]

Re: newbie need advise for my oven

ummm I didn't give anyone my email addy... just called the number. Probably someone selling a stock shipped from china

How thick do they normally come as?

[brickie in oz]

Re: newbie need advise for my oven

I just saw an ad on gumtree for ceramic blankets
Price: $70 per roll 600mm wide x 25mm thick x 3600mm long
BUY 2 FOR $99
My bricks+ blanket= 110mm~ of insulation
So that should be good right?

Users on Gumtree just phish for your email addy so they can spam you, why else do you think the deal was so good?

[gonzo420]

Re: newbie need advise for my oven

I just saw an ad on gumtree for ceramic blankets
Price: $70 per roll 600mm wide x 25mm thick x 3600mm long
BUY 2 FOR $99
My bricks+ blanket= 110mm~ of insulation
So that should be good right?

[gonzo420]

Re: newbie need advise for my oven

I'd be breaking them into manageable pieces (around half a brick each piece) and fill between them like crazy paving, This insulating layer should be at least 100 mm thick.

The bricks are 32x12 and 80mm thick, they are the same size as the fire bricks.
If you say 100mm thick then I shouldn't cut them and I'll use them 'as is' on top of the dome. I guess breaking them apart and do the homebrew mix will make the insulation better but wouldn't it be fine just like this?

I placed a firebrick on the stove this morning with the insulating one on top of it for more than an hour. The temp on top of the insulating brick was 30 degrees. on top of the fire brick was 160 and where the insulating brick touches the fire brick it was 77 degrees.


Uploaded with ImageShack.us

[david s]

Re: newbie need advise for my oven

I'd be breaking them into manageable pieces (around half a brick each piece) and fill between them like crazy paving, with homebrew insulation mix 5:1:1:1:1 (perlite or vermiculite,portland cement,sand, builders lime,bricklayers clay. This insulating layer should be at least 100 mm thick. (You don't say how thick your bricks are).This insulation layer does not have to be strong, the outer shell holds it all in place. It is the air that you want to trap in the insulation layer.

[gonzo420]

Re: newbie need advise for my oven

Yes, you can smash them to create an insulation aggregate, but don't crush them to powder

If I use the bricks halved or aggregate, should I mortar them together or can they remain loose? I will use mesh wire and little mortar on the dome part, then do the final layers of rendering.
If so, I don't need to spend $110 on ceramic blanket is it?

If the above is correct then I just need to buy refractory mortar, water resistant mortar (not sure what to get from Bunnings) and mesh wire and I'm good to go I hope

[david s]

Re: newbie need advise for my oven

Gudday
Could they not be "mortared" together with pearlite and cement mix.
Regards dave

Certainly can and this would be easier than crushing them. The question was can they be crushed to use as an aggregate and I answered accordingly.
Perlite or vermiculite makes a lightweight insulating mixture that is way easier than crushing insulating bricks. But if you have them and they're free they can be used as an aggregate. In my case I wanted a high temperature mix. Both perlite and vermiculite are only good for 1100 C, which is of course way more than you need for a WFO.

[cobblerdave]

Re: newbie need advise for my oven

Gudday
Could they not be "mortared" together with pearlite and cement mix.
Regards dave