Fox James

There is a thread on Donkey pro boards about 3d printing but based on molds and casting.
https://permies.com/t/155825/printed-Peter-Van-Den-Berg#1220996

I cant think of a suitable material to use?

I have seen other folk using printers to make inner and outer molds from foam.

Perhaps a water jet cutter could cut refractory cement but that would be a large expense.
There may be a solid ceramic product that I dont know about but again that would be massively expensive!
Ceramic fibre board might work but ‘A’ it would cause massive and dangerous dust and blunt cutters. ‘B’ it wont stand up to the riggers of a fire box.
Perhaps Vermiculite board but apparently diffacult to get in the States and again would blunt cutters in a second.

Nate, you should study the batchbox design as it is difficult to beat it on shear performance, the design is very well tested and proven.
Also look up Bell chambers as they are largly superseding piped systems.
https://batchrocket.eu/en/

Hi Nate, if you forward  wind my video to around 2minutes you can see my version of a glass front J tube with airwash !

No it is a J tube with a glass front and a few mods but I though the  design and small mass might interest you!
It started life as a standard J tube, I have other videos showing it in a more basic J tube configuration.  
The wood is just dropped in the top as required rather than loading up a big batch.

Hi April, I have found the 4” vortex to run fine without any secondary air, there is a slight temperature difference but that is probably a good thing in my case!
It also runs well without a door but it burns out very quickly that way so I would recommend a door.
Yes you can control the fire by restricting the air but then you will quite likely get smoke on the viewing glass and out of the chimney.
I found that by using the BBQ cast iron under the ceramic glass the cooking temps are just about right, around 350-400c at peak burn but mainly around 250-300c.
To be honest compared to a electric or gas stove or oven, rocket stoves are nowhere as easy to cook on, they are designed to burn hot and fast, perfect for heating a mass but a bit volatile for cooking!
However with my outdoor vortex stove the surrounding bricks and granite worktop get lovely and warn.
The vermiculite board is still looking fine, no noticeable Deterioration so far but I dont expect it to last for ever.
In my case, if the board fails after a couple of years I can just replace the whole unit for £150 and a couple of hours work.

That is not a cheap build so I would use ceramic glass for the door and and consider insulating fire brick for the top box. You may be able to  successfully cook in the top box while the fire is running on coals but you would need door for that too.

The hot plate is best in thick steel or cast iron, you can buy BBQ cast iron plates 12 x 16” maybe use two.

Also you could use a vermiculite box on top of your hot plate to cook in ( I have a video) even with a Rotisserie!  
You can buy wood oven doors with glass, I paid around $200 for the last one I bought or you could get someone like Thomas to build you a custom one.

As Gerry points out, most European standard ceramic fibre products are fairly safe to handle using sensible precautions however, if you should ever need to remove any ceramic fiber that has been super heated then you must be super cautious!
All the ceramic products that I use are rated as body soluble, meaning that the fibers can be broken down by our own body should they get inhaled.  
The issue becomes far more dangerous  if you inhale any airborne fibers once they have been exposed to high heat as the dust is no longer body soluble!
So you can use ceramic fibre board, although it would be best to coat it with some high temperature coating, and just be aware that if you should take the stove down, to be extremely careful of the possible dust in the air.

Hi Rob, I have a few different styles of rocket stove on my youtube channel, some more basic than others but this style might suit your requirements ?

Local woodworking shop sells bags of super dry offcuts £1.50 per bag, gives me 4 hours of burning.