38" Pompeii build

[david s]

I use a similar method using a template. The whole back of the oven is then pretty much covered in one single piece, using the off-cut triangles to fill any gaps at the base. Very little wastage and the blanket sits in place by itself.

[Frenchie]

Very nice, david s!

[Frenchie]

I managed to find a couple of hours a couple of days ago, wired the insulation, fitted mushroom cowl, and first layer vermicrete. Since lit a hotter curing fire (dome getting to 250C now).

JRPizzas suggestion about lath was good, but the lead time was long for me by mail order and I already had chicken wire and vermiculite so I just cracked on with it.

feels like progress.

vermicrete is weird stuff isn’t it! Got a bunch more to do.

[david s]

Yes it is weird stuff. Because perlite and vermiculite are so hygroscopic, a large amount of water is required to make up a workable mix. I usually use 4 litres of water for every 10 litres of vermiculite/perlite, but the amount required does also depend on the grade used (finer grades require more water) as well as the amount of moisture thats already contained in the dry material. The drying time is also dependant on how thick the layer is, but when it has dried it will go white and appear to be dry, but be careful because while it may appear dry on the surface it will be moist deeper in. Judging from your pic, yours still appears moist. If the temperature gets higher, say around 350 C internal, the layer will sometimes crack from the expanding steam. Try throwing a sheet of plastic over the oven during your drying fires to see if there's any condensation on the underside of the plastic. I prefer to allow sun and wind to do much of the drying and for a layer of around 40mm thick this usually takes a week, weather dependant. Sun and wind will dry the layer from the outer surface while drying fires will push moisture out from the inside to the outer surface.

Your oven looks fabulous and I understand your enthusiasm to get it completed.