My first attempt for 42" oven / changed to 36"

[jas0ny]

Question since I am currently building an oven myself, how many layers of FB blanket goes on the outside of the dome? And after the blanket is laid, cant you put just regular mortar over it since its well insulated already?

[George_M]

here's a resource that I used: https://www.directcolors.com/resourc...t-calculators/

I will check the colours. Thanks!

[George_M]

Question since I am currently building an oven myself, how many layers of FB blanket goes on the outside of the dome? And after the blanket is laid, cant you put just regular mortar over it since its well insulated already?

2-3 layers i think is ok.
Check post #281 for your second question.

[jas0ny]

Got it on the vermiculite. The thickness should be half thickness of the blanket? Or just a thin layer is fine? Not sure I understand post 281.

2-3 layers i think is ok.
Check post #281 for your second question.

[George_M]

I add perclrete not vermiculite and I add almost the same thickness as blanket. Not a thin layer. You need insulation.so the more insulation the better result

[cnegrelli]

Question since I am currently building an oven myself, how many layers of FB blanket goes on the outside of the dome? And after the blanket is laid, cant you put just regular mortar over it since its well insulated already?

Mortar or Stucco?
Everything I've read is that the V-crete is suggested not only to add extra insulation but to regain the shape you are looking for to an igloo style build, before doing the stucco layer. It's a very cheap way to add additional insulation as well as get the igloo back into the shape you need for final finishing.

As for thickness, it's all dependent on how much insulation you are looking for and the R-value of your blanket. Post #281 from David was simply explaining that it's hard to render Stucco onto the blanket (lumpy etc) and that a layer of V-crete would get you something firm, smooth and back to the shape you are looking for, before Stucco.

[jas0ny]

I bought the FB Insulation Blanket from fornobravo hoping that is well enough insulation so I wouldnt have to add more mass. When I spoke to the tech over the phone he mention that a few layers of blanket should be enough and not much of a need for more insulation unless you wanna spend $$. So putting stucco over should be fine, but what i gather is i should put v-crete or vericulite over the blanket to get the igloo back in shape?

[SableSprings]

I bought the FB Insulation Blanket from fornobravo hoping that is well enough insulation so I wouldnt have to add more mass. When I spoke to the tech over the phone he mention that a few layers of blanket should be enough and not much of a need for more insulation unless you wanna spend $$. So putting stucco over should be fine, but what i gather is i should put v-crete or vericulite over the blanket to get the igloo back in shape?

The ceramic blanket is going to provide plenty of insulation for your oven. Since it would be nearly impossible to apply stucco directly over the ceramic blanket...you first need to provide a firm base. In addition, stucco is generally applied in a relatively thin layer which won't allow you to easily correct the "lumpy igloo" shape that results from just the blanket cover. You want to create a reasonably thick layer--at least a couple of inches ( IMHO )--to smooth out the shape of the dome/igloo. Many of us simply opt to do this with either a 10:1 mix of perlcrete or vermicrete (or build an enclosure that's hides the blanketed igloo/dome, mouse proofs, and protects the blanket from water & critter infestations ).

First wrap some chicken wire or hardware cloth over your insulated dome. Secure it as tightly as possible and keep it as close to the shape of the dome as you can. Next, apply either a layer of insulated cement (p-crete or v-crete) over the dome and use it to shape and smooth to your personal specs. Once you've got a relatively smooth and firm base layer over the dome, the stucco will be much easier to apply. It's also perfectly acceptable to apply homebrew or stucco base mortar over the wire mesh/blanket...you just are trying to provide something for the stucco to have as a firm base for adherence & to build up the visual shape/form you want for the oven.

Hope this helps...

[George_M]

Hi,
2inch perlcrete layer around my dome is good enough?

[SableSprings]

Yes George, you have plenty of insulation with the ceramic blanket and 2" of perlcrete over the blanket will give you a good base for the final stucco layer(s). As David S pointed out earlier, when you keep adding dome structure up against those two side walls it's going to get more and more difficult to work (and keep that igloo shape). It's also going to be difficult to keep the area behind the oven from collecting lots of cobwebs & dust. Your oven looks really good and I'm sure it will be even more impressive when you do the final finishing touches.

[George_M]

Thanks sablesprings for your reply.
As for the shape,i love the ingloo style and i accept the difficulties to clean it behing from dust etc.
Now, i need to buy cement pigment powder to finish my oven.

[George_M]

Hi,
It's time to render my dome.
What mixing ratio to use for dome rendering?I will use white cement to add powder color in the mix.

[George_M]

Update!

[George_M]

Mortar or Stucco?
Everything I've read is that the V-crete is suggested not only to add extra insulation but to regain the shape you are looking for to an igloo style build, before doing the stucco layer. It's a very cheap way to add additional insulation as well as get the igloo back into the shape you need for final finishing.

As for thickness, it's all dependent on how much insulation you are looking for and the R-value of your blanket. Post #281 from David was simply explaining that it's hard to render Stucco onto the blanket (lumpy etc) and that a layer of V-crete would get you something firm, smooth and back to the shape you are looking for, before Stucco.

Which materials to use to make the final finish layer?
And what ratio?

[George_M]

The crack in the position you describe is quite common in ovens that have no thermal break or expansion joint between the oven and the flue gallery. This expansion joint allows the expanding oven to move a little without putting stress on the outer arch of the flue gallery. The other problem is the uninsulated flue gallery itself. Stress on the refractory is increased when the inside gets hot but the outside remains cool. By insulating around it this temperature difference is reduced and thereby reduces cracking tendency.
Don't worry about the crack, it probably won't get worse. As they say there are two kinds of ovens, those with cracks and those with owners who lie about their ovens having no cracks.

Hi David,
Today i made some pizzas for first tray.
I reach very high temperatures and the oven was almost saturated.
I see the same crack again and the corner of the brick just a little down.
Which is your opinion on this?Need some protection or is not a problem?