A method of manufacturing a hybrid structure (100) having a layer of CMC
material (28) defining an interior passageway (24) and a layer of ceramic
insulating material (18) lining the passageway. The method includes the
step of casting the insulating material to a first thickness required for
effective casting but in excess of a desired second thickness for use of
the hybrid structure. An inner mold (14) defining a net shape desired for
the passageway remains in place after the casting step to mechanically
support the insulating material during a machining process used to reduce
the thickness of the insulating material from the as-cast first thickness
to the desired second thickness. The inner mold also provides support as
the CMC material is deposited onto the insulating material. The inner
mold may include a fugitive material portion (20) to facilitate its
removal after the CMC material is formed.