Done mold out of clay

[The Plumber]

Hi
I am planning on building a pizza oven and I’m in no rush so spending time pouring through sites and forums. I have been fortunate to find plenty free natural clay in a huge construction area very close to where I stay. A mate is the chief Civil engineer on site, so really as much as I need. My question is, can I possibly cast/create the dome base structure out of clay instead of building from bricks? If so, what is the best option, home brew as I have seen discussed, a more natural cob with dried hay or by adding stainless steel needles for for structural strength? Has anyone done this and does the clay hold up or just crack badly?
I would then cover in a ceramic blanket and potential perlite mix on top of that.

[SableSprings]

Welcome to the forum! Cob ovens using straw for internal strength/insulation has been used for centuries...but mostly in climates that are very dry. Obviously, cob is very sensitive to weathering and if not protected (or in a dry climate), tends to need either a lot of repair/maintenance or a cover. If you have such an great source of clay, there is a book by Kiko Denzer that is dedicated to cob oven building. It's still a very labor intensive project and (IMHO) is a lot of time spent on something that has a short "half-life". I think you might have fun doing a small cob oven and learning about using it...but I would be looking at it as a learning process and not worth stainless steel needles, ceramic blankets, or even putting a perlcrete insulation base under and/or over.

As attractive as "free" is...you do get what you pay for...