Stainless 304 Build?

I watched this guys build using stainless steel for his burn box and riser. Appears to work well. Since stainless has a melt temp over 2500 degrees F, I can't imagine any steel degradation occurring, can you?    

Well there are rocket stoves and there are ROCKET stoves!
That one is not insulated, not designed to run for several hours every day and is pretty small … so yes the stainless should last quite well.
However, stainless will deteriorate, the process  is  known as intergranular corrosion, this corrosion results from heating stainless between 550C and 850C.
This causes chromium to precipitate from the stainless steel and reduces the ability for the passivation layer to regenerate. (I dont really know what that means but that is what is says on Google)
Also stainless is very prone to expand and contract when heated and cooled and that is one of the main reasons it is not used very often for stoves.
I have tried using it for pizza oven doors but it warps really badly.

Fox James wrote:Well there are rocket stoves and there are ROCKET stoves!
That one is not insulated, not designed to run for several hours every day and is pretty small … so yes the stainless should last quite well.
However, stainless will deteriorate, the process  is  known as intergranular corrosion, this corrosion results from heating stainless between 550C and 850C.
This causes chromium to precipitate from the stainless steel and reduces the ability for the passivation layer to regenerate. (I dont really know what that means but that is what is says on Google)
Also stainless is very prone to expand and contract when heated and cooled and that is one of the main reasons it is not used very often for stoves.
I have tried using it for pizza oven doors but it warps really badly.

I would imagine it to hold up quite well. There are various grades of stainless as you likely know. My guess is it would outlive the fabricator hence rendering untrue to "not use metal" in your fabrication of your burn tunnel. Make it bigger if required IMO.  

You can use metal in a smaller, uninsulated rocket-style stove and it may last, but it will absolutely be less efficient than one built to established standards, and stainless steel is considerably more expensive than other materials. You are welcome to experiment with it; please publish the process and the long-term results, not just the initial build/test. Also, proper emissions testing with professional equipment is the only way to compare with the current best practices.