Fox James

New video…..

Well that is fantastic to see you have fired it up and it is working but….. the construction will be holding moisture and it will take several fires to completely dry out .
Even the ceramic fibre will hold moisture but the bricks can be really stubborn and take an age before they are allowed to operate at max efficiency.
It is always best to do this slowly to avoid cracking any bricks!

When I joined this forum, the gap was a frequent discussion and lots of people offered to solve the  question with calculations and advice.
This subject really confused me and it seemed like a critical measurement but as it tuned out there is a minimum sized gap but as Jordan points out anything above the minimum is fine.
However if you are using the barrel top for cooking or boiling, then the gap becomes more important.
The hight of the riser may be more critical but again it seems a minimal hight is more important to achieve than a max hight.

Hi Tim, I use the basic SkamoStove Board  is suitable for hot face or back up insulation of all refractory constructions. It will not decompose even when subjected to direct flame, but the maximum service temperature should be taken into consideration. This one is rated for 1100c or around 2000f they do make other more expensive boards but I prefer the cheap one to play with!
It is 25mm thick.

If you are concerned then perhaps use split brick and wrap that with ceramic fibre?
How do you intend to close the top of the bell or clean out the floor ash?
Personally I would want to have access to the core and riser.

Delicate in this context means the coating has been baked hard to the extent of being fragile, it is possible to crack it by pushing it with a finger.
You dont have to coat the fibre with anything and it should last for years but, it will by then have become a hazardous material and potentially deadly if breathed in!

So ‘delicate’ also means to me, that I have to be very careful not to break the coating that is containing the danger, but delicate does not mean the riser would not still Function.

I must of missed that post!
Funny enough I just used my old 5 minute riser in my last video and I felt ill at ease just touching it haha…

That particular one was used for at least two years and is coated with Vitcas ceramic fibre rigidiser.

It has worked and appears to be still forming a crust on the surface though be it, pretty delicate.
The zircon works ok on ceramic board and I think might be ok on ceramic mat but it has badly cracked and flaked on vermiculite board.
Vitcas are experts and suggested their  riigidiser would be the most suitable product they stock however that was several years ago and they have new products now.
Personally I am trying my best to stay way from ceramic fibre products and I am using cast thin wall risers  with an outer tube filled with loose vermiculite. (Also can seen in my recent videos)

A bit more fun…..

Super wool needs to be treated with respect, look for body soluble version as they are safer to work with but still be aware of the facts of the individual product and use a mask.
Also be aware that once the material has been heated, it could be a serious heath hazard if it is disturbed and the fibres become airborne
There are alternatives but none are as effective or as easy to install.

As I am sure you know, steel is not going to be a long lasting material to use as a hot face in any insulated rocket stove.
The top gap on a 5” should not be less that 2.5” but there is not really an upper limit so 3-4” will be fine.

A lot of European style stoves are quite advanced, they have to pass quite strict safety and ani pollution levels.
Most use secondary air and are lined with vermiculite.
I made this thread https://permies.com/t/208777/European-box-stove