Planning out my first WFO

[M_K]

Hey,

First post here as I have more or less just been reading through existing posts trying to plan this thing out. My goal is to create something a bit light weight in case I need to move it since I don't have a permanent home for it in the backyard just yet. My question is around the dome itself. If I constructed it with the following layers would it be sufficient to contain the heat in the oven?

First layer (starting form the inside) 2" of portland/perlite 1:5 mix
Second layer 2" ceramic blanket
Third Layer stucco to protect it from the weather as it will be stored outside through a Canadian winter.

[deejayoh]

Welcome to the forum!

For building an oven, "a bit light weight" is a relative term... Firebricks alone probably weigh 1500 pounds. If you want to move an oven I'd focus on the support structure. There are a couple of examples of ovens built on wooden frames. Not sure how they turned out. I would think that if you think you will need to move the oven, look into casting it.

on your insulation plan, I would start with the ceramic blanket. Its your most effective insulator. Then the perlite, then the stucco. Several builds (gulf, utah beehiver) have gone that way with good results.

[M_K]

Thanks and sorry for the lack of detail. I am planning on casting the first layer 2" of the portland/perlite mix. This would be the inside of the dome that is exposed to the flame. I am not going to be making the dome out of fire brick because of the weight it would add. You are suggesting start with the ceramic blanket but that would expose it to the flame so I think there was maybe a bit of confusion as to how I was listing out the layers.

As for the weight reduction I am looking at a way to reduce the weight excluding the base so any suggestions on light weight materials to use from the "Hearth up" is more of what I am looking for.

[RandyJ]

None of that can be exposed to the flame inside the oven. You will need some kind of castable refactory material. Then the blanket then the pearlcreet then the stucco. If you need it light you will need to go smaller. You should look at what DavidS did for his.

Randy

[deejayoh]

What Randy said. I assumed all the materials you mentioned were going over your dome. The internal dome needs to be a refractory material. Firebrick or castable refractory, That's what makes the whole thing work. It absorbs, retains, and reflects heat. Perlcrete is a) an insulator so it does the opposite of retaining heat and b) not a terribly strong material. It would probably collapse with the first fire if you managed to stand up a dome made out of it.

you might just want to wait until you figure out a suitable place to build an oven. "Heavy" is one of the defining characteristics of a WFO!

[RandyJ]

If you really want a movable oven you should look at some of the fully built ovens offered by forno bravo. They are available with metal stands and Castors I believe. That might be your best bet. Otherwise a light build might be in the 3-5000# range. My enclosed oven is in the 16,000# or more range.

Randy

[dakzaag]

The guys are right on about trying to use a pericrete mixture for your dome. It will constantly be shedding stuff onto the floor if it survives the form removal at all. You can do a smaller size oven, maybe 28" or even smaller and you could build it out of half brick so it would be 2" thick instead of 4.5". It will still end up in the 2000# range probably once it is all finished. I know of a similar build I could reference you to if you are interested.