48" brick oven from Melbourne

[Dario]

Re: 48" brick oven from Melbourne

Hey Dario,

How are you going, I'm doing a similar build to you. My cooking area is 1m in diameter.

I started a few weeks/weekends ago and today I'm going to insulate my dome.

How do you plan on building the dome? Are you using sand or are you building a frame to follow?

Accrig
I've used sand, you can see on the pictures now I'm thinking about next step to finish the front arch chimney to.
I haven't make desision am I going to put blanket on the dome or add extra mass. What have you done with yours?
Cheers Dario

[UtahBeehiver]

Re: 48" brick oven from Melbourne

Dario, your build is going exceptionally fast. Your proposed inner arch looks fine but you will probably need to bolster your vertical walls since the shape of the arch has a natural tendency to push out the vertical wall sections out.

[cobblerdave]

Re: 48" brick oven from Melbourne

Accrig
I've used sand, you can see on the pictures now I'm thinking about next step to finish the front arch chimney to.
I haven't make desision am I going to put blanket on the dome or add extra mass. What have you done with yours?
Cheers Dario

G'day Dario
You have 120 mm (4 1/2 ins ) mass on the dome and 75 mm (3 ins) mass on the floor. Pretty much what I have. Insulated you'll be able cook pizza on fri night, bread sat morning, roast sat lunch and you'll probably get in a slow stew sun. If you need more heat in the oven you can always take a warm oven up to temp faster than a cold one. If you increase the mass to much it will only take you longer to heat and that heat will be wasted during the times that your not using it during the week. Put a layer of homebrew mortar to smooth things out and I recon that will be all you'll need.
Insulate the sh@t out of that and you'll be cool
Regards dave

[Dario]

Re: 48" brick oven from Melbourne

G'morning,

Thanks Russel, Dave
Very much appreciate your advice
I've worked my @ss of since friday the input shows at the end but i can feel on my back . hehe
Dave homebrew mortar you mean sand and GP cement, what ratio would you use ?
Should i keep my dome under the tarp while i am building it ?
Can i trim CalSil board to the size of my dome now ?


Thank you

[cobblerdave]

Re: 48" brick oven from Melbourne

G'day
Not quite you true "home brew" but I recon for a sparging layer...,1part Portland cement, 1 part hydrated lime, 3 parts sand. All measured by volume not weight.
Regards dave

[Dario]

Re: 48" brick oven from Melbourne

Thank you Dave.

[Greenman]

Re: 48" brick oven from Melbourne

Hey Dario - You are certainly powering along with your build! You will definitely need to better buttress the sides of your entrance arch or failure could be a real prospect.

This link shows the lines of thrust of arch constructions. Auroville Earth Institute

Not sure about your extra calsil board but I expect that any that does not protrude past your insulation layers would not need to be removed.

[Dario]

Re: 48" brick oven from Melbourne

Ok thank you Steve,

I was thinking to install stainless flue at the top nothing fancy or heavy just modern design like what Laticeeper have on his WFO.
Nice and simple design ?

http://www.fornobravo.com/forum/51/n...-18249-66.html

[Greenman]

Re: 48" brick oven from Melbourne

That does look good. Mine is basic, just the SS flue fitted into a slot cut in the bricks and caulked with heatproof rope. Next time I will build a full arch entry.

[Acrigg]

Re: 48" brick oven from Melbourne

Hey Dario,

Sorry for the delay,


I insulated my dome with perlite cement with a bit of fire clay added to the mix. I then rendered over with home brew, cement lime fireclay sand 1:1:1:3

If I get to much heat loss I'll do another layer but as the other fellas said I think there will be plenty of thermal mass.


I'm curing my oven over the week and will do my first real fire and cooking this weekend .

[Greenman]

Re: 48" brick oven from Melbourne

Thermal mass and insulation are two different things. Not sure that the addition of fire clay will help with insulation and the thickness of the perlite cement or vermicrete is critical depending if any other insulation material is used.

Adequate insulation needs to be in place before the render goes over the top or it will just get untidy. Without decent insulation you could end up with a wham-bam-thanks mam oven. Building an oven is a bit of work and the extra effort to get it close as you can to right is worth the doing. IMHO

[david s]

Re: 48" brick oven from Melbourne

Hey Dario,

Sorry for the delay,


I insulated my dome with perlite cement with a bit of fire clay added to the mix. I then rendered over with home brew, cement lime fireclay sand 1:1:1:3

If I get to much heat loss I'll do another layer but as the other fellas said I think there will be plenty of thermal mass.


I'm curing my oven over the week and will do my first real fire and cooking this weekend .

This sounds to me like a recipe for outer shell cracking. 3:1:1:1 is too rich a mix and you are likely to get cracks. In addition, if you layered perlcrete directly over your dome without a blanket layer between it and the dome it's likely to turn to steam very rapidly unless you dried the perlcrete out really well before applying the render. Remember that around 1/3 of the perlcrete volume is water and the greater part of that needs to be removed. If you end up with some big cracks in the outer shell, leave them and continue to use the oven until it's dry, then give it another render layer and you should be ok.

[Acrigg]

Re: 48" brick oven from Melbourne

Hi David,

Thanks for the advice, I did layer the perlite/vermiculite cement over the dome without a blanket 3-4 inches. I left it about a week before rendering.

If been starting the fires small and growing then to reduce and cracking. Only a few small cracks so far.

If it gets to bad then I'll put down some blanket or fiberglass insulation and apply another layer of perlite and render again.


What sould I seal the outer skin with to reduce water soaking in. It is open to the elements. I have read people use an acrilic sealer?

[david s]

Re: 48" brick oven from Melbourne

If the cracks are bad just render over them again. Don't start adding more insulation over the oven now. Your outer shell only serves to keep out the weather. Use an acrylic render over your cement render, but wait until you've had around 10 decent cooking firings, otherwise trapped moisture may create some blistering under the acrylic layer. You can paint over the acrylic render with any acrylic house paint, it works fine.

[NCMan]

Re: 48" brick oven from Melbourne

building an oven is a bit of work and the extra effort to get it close as you can to right is worth the doing. Imho

+1..........