A method of curing a composite material. A tool is heated using microwaves. At least a part of the composite material is shielded by reflecting microwaves away from the composite material with a shield. Heat is transferred from the tool through the shield to the composite material. The tool comprises a material which is sensitive to microwaves so that, when microwaves are incident upon the tool, some of the microwaves are absorbed by the microwave-sensitive material, thereby heating the tool.