Corrosiveness to copper from petroleum products by Copper Strip test
7. Reagents and Materials
7.1 Wash Solvent - Any volatile, less than 5 mg/kg sulfur hydrocarbon solvent may be used provided that it shows no tarnish at all when tested for 3 h at 50°C (122°F). 2,2,4-trimethylpentane (isooctane) of minimum 99.75 % purity is the referee solvent and should be used in case of dispute. (Warning - extremely flammable, see A2.1.)
7.2 Surface Preparation/Polishing Materials, 00 grade or finer steel wool or silicon carbide grit paper or cloth of varying degrees of fineness including 65-µm grade (220-grit CAMI-grade or P220 FEPA-grade); also a supply of 105-µm (120-grit to 150-grit CAMI-grade or P120 to P150 FEPA-grade) size silicon carbide grain or powder and absorbent cotton (cotton wool). A commercial grade is suitable, but pharmaceutical grade is most commonly available and is acceptable.
7.3 Copper Strips Specification - Use strips approximately 12.5-mm (1/2-in.) wide, 1.5 to 3.0-mm (1/16 to 1/8-in.) thick, cut approximately 75-mm (3-in.) long from smooth-surfaced, hard-temper, cold-finished copper of 99.9 + % purity; electrical bus bar stock is generally suitable (see Annex A1). The strips may be used repeatedly but should be discarded when the strip’s surface shows pitting or deep scratches that cannot be removed by the specified polishing procedure, or when the surface becomes deformed.
7.4 Ashless Filter Paper or Disposable Gloves, for use in protecting the copper strip from coming in contact with the individual during final polishing.
