Haven't seen these before and, checking them out, just noticed this on their website.
"Plumos fire pits are designed to contain a moderate fire. Do not overload the fire pit. To build a coal bed for cooking, start with a moderate fire and gradually add more firewood as the fire burns down rather than building a large fire and waiting for the fire to burn down. This allows for more control over heat, builds a coal bed faster and is safer to manage.
Can I use heat beads or brickettes in a Plumos?
Heat Beads and Brickettes tend to burn significantly hotter than firewood which can lead to damage of the walls if left to burn too hot for too long, we recommend using only firewood for this reason. If you must use heat beads we advise building a coal bed from firewood first then use heat beads in addition to maintain heat for cooking."
With 3mm mild steel plate, maybe your fire was too hot for the unit? Just guessing.
Keith
