Fox James

Paul LeMay wrote:Yes, I am interested in avoiding the steel oil drum design or the steel rocket tube. All brick. Thanks

Hi Paul, I have read your desire to gain info on masonry heaters only but, I think that once you grasp how a modern rocket stove and brick bell is constructed and how it works, it might broaden your prospective and change your mind.
From the outside there need not be any difference in appearance  at all, in other words a rocket mass heater is fundamentally the same apart from the rocket engine is more efficient and the whole system easier to build.
I can understand the confusion in relationship with the somewhat dated oil drum designs but that need not be the case at all.
In very basic terms….  a modern rocket mass heater comprises of a very efficient fire box with a door and viewing window that is situated inside a brick enclosure.
The brick enclosure only contains the rocket stove engine and no complex additional brick work, the actual size of the enclosure is defined and documented and is based on volume so it can be made into many shapes to fit your requirements.
So in summery, a modern rocket mass heated, is a very direct alternative design, that can look from the outside,  virtually identical to a more traditional masonry stove.

I think it is a well made video, good workmanship and he even mentions the dangers of using ceramic fibre but still uses the stuff!
I for one would not want that inside my home, every time you attend the fire you could be exposing yourself and family to toxic dust!
I did actually ask that question in the comments some time ago but never got a response.

Hi Ben, I am just checking that you know the risk involved with ceramic fibre?
Just be very aware that if you should ever need to expose or manipulate the riser once it has been fired, it will release millions of toxic particles into the air.
If it is sealed in and not accessible then you are good?
There are products available to seal the surface that work to an extent.

Good luck with the new build, exciting for you and hopefully a Success!
PS good point with the ceramic fibre riser as that would be extremely unhealthy option!
If you even touch the stuff once super heated, it just produces  so many air born particles!

It might work with a square nozzle or perhaps for ease of build, the latest trend of a triangular shape!
In my case, I would try using vermiculite board rated at 1200c and proven to last for years in the vortex stove but it is 25mm thick.
Perhaps a kiln shelf but not so easy to join the corners.
However I would agree from what you have said that thin metal might well be the best option.
Cast iron tube might work a bit longer than stainless but hard work drilling the holes!

I use a piece of 1” steel mesh in my J tube vortex stove and regard that as a disposable component, it last about 20-30 burns but is very cheap and easy to replace.
On that basis and certainly for your own use, a disposable part might be just fine?

Does the nozzle have holes in the top?
What size is the fire box, does it have a door?
Have you calculated what all the holes add up to in relation to the system size?

Sounds great!
So you have a fire box with a hole in the ceiling and an exit somewhere out of the riser?
Can you post a basic diagram?

Lots of effort and time but you must enjoy the satisfaction as well?

Yes there are lots of post already on the forum, just type in Permies Maple Sap Evaporator into google and there plenty of forum links.

Well if you want a really good heater that gets very hot but does not produce any smoke, then you need to insulate the fire box and heat riser.
You can just make a basic J tube with no secondary air or any complicated accessories, if it is made to know specification then you will have a very effective patio heater and cook stove.
The problem with using steel is … as soon as you use insulation, the metal will start degrading and not last very long at all.
If you are only going to use it on an occasional basis the is might be fine for you but if you want to use it regularly , then you need to consider using a more long lasting material that steel.
My own J tube in a barrel, built with insulating vermiculite board, will heat a large area radiating heat from the sides  at around 300c.
You could have a circle of 20 friend sitting around it and cook food for them all very easily.