A field-ready oven (10) has reinforced telescoped side walls (70) that extend and hold a base (51), shelf, tray support (20 ) and cover spaced apart. A low air intake (17) and a semipermeable membrane (110) deliver air and vapor fuel to catalyst pads (31) on the shelf. Radiant heat from exothermic reaction is diffused over a bottom of a tray (20). Hot gas circulates around the diffuser (80) and tray (20) with a chimney effect before exhausting. A lid (53) on the cover lifts for access to the tray. A fuel container (100) in the oven forces fuel through a capillary restriction to limit fuel flow. A spring (107) in the container is released to start fuel flow.
