On putting the item to melt in, the stack is ejected whole and the furnace gets converted into opening-less vanilla furnace with duplicate stack of 1 item, which drops regular furnace on break. Happens instantly even with several Nether Furnaces. Botania 141, Forge 1240, Natura 2.2.0.1.

Speaking of Exoflames, would be nice (but probably overpowered) if they could fuel TC4's Alchemical Furnace and various generators.

Mod compatibility like that needs to be handled by the other mods, botania has something in the API just for this I believe.

The Exoflame will now ignore other mods' Furnace blocks unless they specifically opt in with the API interface. Fixes a dupe with Natura Nether Furnaces.

Hurr.