Methods and apparatus are provided for making a rotor blade spar (14) from composite material wherein a multi-component mandrel (10) is used to form the composite spar (14). The mandrel (10) is made using a number of components (38,44, 50, 56) that are assembled and held in place using a roller assembly(62). The roller assembly (62) is removed after pre-cure lay up and compaction of the composite material. Once the roller assembly (62) is removed, the remaining mandrel components (38, 44, 50, 56) can be separated from each other and easily removed from the spar (14). The mandrel components, including the roller assembly ( 62 ), can then be re-assembled and re-used to form additional composite spars.