BONDERITE M-CR 871 AERO ALODINE 871 BONDERITE® M-CR 871 (known as ALODINE 871 TOUCH-N-PREP) Coating is a non-hexavalent chromium dry-inplace conversion coating designed for use on aluminum and its alloys. The applicator used to deliver this product provides an easy and safe method of repairing bare areas of aluminum surfaces.