Has anyone built a rocket-mass-kiln?

What’s the hottest you can get a cavity for one of these things? I did a cursory search for rocket mass kiln and got no results!

Hi Shahar;
You used the wrong name to search.
What you are searching for is a "Rocket Kiln"
There are plenty of hits on Google.

Here's one built at Paul's place, Wheaton Labs.

https://permies.com/wiki/177379/harvest-clay-and-make-pottery#1393607

Here's a thread with photos and videos of that kiln.

https://permies.com/wiki/177379/harvest-clay-and-make-pottery#1393607


Plans for the rocket kiln are in this bundle. The rocket engine would also be needed, if I remember right. Those plans are included in the bundle.
https://permies.com/wiki/214139/Tech-Lab-Plans-Bundle-builds

Good luck!