Aircrete Refractory Mold Oven

[Lou M]

Hi, a new follower to the forum here. I am in search of some answers to the ideas of building a molded oven and using the technique of using refractory cement with all of the additional stuff for adding strength but using the methods for aircrete DIY manufacturing.
Has anyone done this on the forum?
What are the experts thoughts, pros and cons?
What materials and formulations of mix would be best if so?

My ideas is to make a wood/ metal foundation on large caster wheels. Create a fiber glass mold of which is shaped like the Amphitheater designed clay oven. make the Mold between 4" thick all around for strength yet lightweight.

Is this a pipe dream or something that is durable.
I hear topics on oven chipping or flacking during the curing process and first fires, would this even be a problem with refractory cement?

I would love everyone's input before I jump into this project! The wife wants this oven made yesterday...lol!
Thanks
Lou M

[david s]

If you are planning on making your own castable mix with refractory cement and the properties required "refractory cement with all of the additional stuff for adding strength",
then you should consider purchasing a dense castable refractory from a refractory supplier. This contains the cement, high temperature aggregates, burn out fibres and other goodies formulated and tested and will give you good results. The drawback is that it's relatively expensive. If you are looking for an alternative that's not quite as good, but substantially cheaper, you can use the home-brew mix 3:1:1:1 sand, portland cement, hydrated lime, powdered clay. But you need to add some burnout fibres or risk steam spalling when firing and expelling moisture.
Regarding aircrew, you really don't want a lot of air in the inner dome as it reduces thermal conductivity as well as strength. It is better for the inner dome to be dense and strong, then insulate it well over the top. You could use aircrew here, but there's a fair amount of mucking around to generate the foam unless you plan on doing this on a continuing basis. I've done some experimenting with it and could only purchase 20 litres of the concentrate. That is enough to last me more than a lifetime. See here on Foamcrete.
https://community.fornobravo.com/for...rete#post16031

Timber stands are generally a poor choice because of movement and deterioration from weather, steel or masonry far better as is stationary rather than mobile.

A fibreglass mould to make a single casting is both expensive and time consuming. A simple sand mould far cheaper, easier and allows casting in situ. I suggest you read a lot more about other builds before settling on a design and procedure.
Here's a start
https://community.fornobravo.com/for...and#post396954
https://community.fornobravo.com/for...sea#post400413

[Lou M]

Mr David, thank you so much for your wisdom. I've been reading and absorbing as much as possible. I'll get this till it hurts in the brain, I'm sure to have more questions soon.

Thanks,

Lou M