Oven on wheels

[david s]

Re: Oven on wheels

Do you think its better to do a vermiculite "inlay" in the slab before you pack the floor or (depending on the quality and thickness of the brick) just the floor straight on the concrete?

No you must insulate under the floor if you want the oven to work properly. Follow the plans.

[wotavidone]

Re: Oven on wheels

I always think you should insulate under the oven, whether you intend to insulate the dome or not.
This is because, if you change your mind, there is no practical way to install under oven insulation later.

3.9 inch dome is good. If you use the 60mm bricks, there will be a couple less courses to lay, but the triangle in the vertical gap will be a little more pronounced, and my seat of the pants feel is that 50 mm floor is just a little thinner than optimum, so the 60mm bricks would be good there two.

I've built three ovens. In each case I've built the inner arch then run the dome off that see the picture at the link below.

http://www.fornobravo.com/forum/8/ne...tml#post167578

After doing the dome, with its inner arch, I then build a free standing entry arch in front of it.
Others lay the inner and outer arches as one construction. Personal preference, I guess.

[RaymondW]

Re: Oven on wheels

Please excuse the stupid question, but how did you determine the angle to cut the bricks on the dome side of the arch?

[wotavidone]

Re: Oven on wheels

Please excuse the stupid question, but how did you determine the angle to cut the bricks on the dome side of the arch?

There are no stupid questions, only stupid answers.
It's a lot easier to do than describe.
I drew a circle that was the intended inside diameter of the oven. Then I decided what the width of my opening should be. Then I decided I wanted the inner face of the arch brick to be about 50mm.
That gave me a line that was 100mm longer than the opening I wanted. So I drew that line so it intersected the circle at those measurements. I marked the dimension and the centre on a stick. I sort of sliced off an arc that had a straight side that was the measurement I wanted. I was then able to use a straight edge from the centre point of the circle to draw a line to the point where the straight edge crosses the intersection.
I've had a go at drawing it in paint to give you the general idea.
I found the angle is slightly less than 45 degrees, so I just cut the bricks at 45. This way I ended up with a little bit of a wedge of mortar, with the thin end of the wedge on the inside of the oven. This matches what happens with all the other bricks. If you cut it exact, there is no room for mortar unless you have a thick seam facing the fire, which you don't want if it is practical to avoid it.
Hope this helps.
Once you build the arch, you will find that as every thing curves around it all sort of follows. On mistake people make is to not have the arch set far enough back into the oven. Since the arch is usually a little bit more than a semicircle to get the height, it doesn't exactly fit the hemisphere of the dome. You might have to set it in 13mm/half an inch to ensure the dome meets the arch at the top properly.

[wotavidone]

Re: Oven on wheels

Come to think of it, the entrance is always at least half the internal diameter of the oven. So the theoretical angle will always be a little less than 45 degrees, if any sort of internal face is left on the bricks of the arch.
I reckon it'd almost always work out just right if the angle is 45 degrees.

[wotavidone]

Update. 7 years after I started laying bricks, the oven is going well.
Can't see any structural issues. I think one brick in the inner arch has a hairline crack in it.
Floor bricks OK. Can't see any internal bricks cracked. Pretty sure that some of the mortar isn't still adhered to some of the bricks.
However not crumbling anywhere I can see. With the dome structure the mortar really is gap filler rather than glue so all is good.
If you can't afford firebricks and proper refractory mortar, you really can do a good oven with fired clay pavers and homebrew mortar.

Had to take time out for some surgery, but last Wednesday I got to fire the beast up and cook a 90 sec margherita.
Scored some 00 flour from the local Coles supermarket for $2.20 per kilo.
Got the floor at 430C per VPN instructions, dome was off scale, so a bit more than the 480C minimum, but that's OK since my oven isn't a low dome Napoli oven.
Really can't beat the flavour of a simple flour water yeast and salt dough that has been fermented for more than 24 hours and superheated for 90 seconds max.

[cobblerdave]

Gday Mick
recon it’s time to bump this