Abstract: A lining for a compressor case is provided. The lining comprises a layer of primer applied to an interior surface of the compressor case, and at least one layer of a seal compound applied to the layer of primer. The primer has been found to significantly improve the bond strength between the base metal and the coating. Also, the primer provides a waterproof coating at the bond interface, which prevents any moisture from creeping under the plastic and causing material break-out. The waterproof coating also provides an increased corrosion resistance to the base metal and stator vanes where the plastic lining has been applied. A method of lining a compressor case is also provided, comprising applying a first layer comprising a primer to an interior surface of the compressor case, and applying at least one second layer over the first layer of primer, the at least one second layer comprising a seal compound to line the compressor case.