FED-STD-791D
5.3 n-Hexane (ACS Grade) non-corrosive (as determined by ASTM D 130)
[1,3,0].
5.4 Acetone (ACS Grade) [1,3,0].
5.5 Polishing materials.
5.5.1 Fine silicon carbide or alumina grit paper.
5.5.2 240-grit silicon carbide paper.
5.5.3 150-mesh silicon carbide grains.
6. PROCEDURE
6.1 Prepare finish of copper strip as follows:
a. Surface preparation - Remove all blemishes from all six sides of the strip with
silicon-carbide or alumina grit paper of such degree of fineness as is needed to
accomplish the desired results effectively (see Note 1). Finish with 240-grit
silicon carbide paper, removing all marks that have been made by other grades
of paper used previously. Immerse the strip in acetone (see Note 2) from which
it may be with-drawn immediately for final polishing or in which it may be
stored for future use.
NOTE 1:
As a practical manual procedure for surface preparation moisten it with
kerosene or acetone and rub the strip against the paper with a rotary
motion protecting the strip from contact with the finger with an ashless
filter paper. Alternatively the strip may be prepared by use of motor
driven machines using appropriate grades of dry paper or cloth.
Caution. Acetone is both toxic and flammable. Use only in a well
NOTE 2:
ventilated area. Do not breathe its fumes nor allow it to come in contact
with the skin. Keep all flames away from the acetone.
b. Final polishing - Remove a strip from the acetone. Holding it in the fingers
protected with the ashless filter paper, polish first the ends and then the sides
with 150-mesh silicon carbide grains picked up from a clean glass plate with a
pad of absorbent cotton moistened with a drop of acetone. Wipe vigorously
with fresh pads of absorbent cotton and subsequently handle only with stainless
steel forceps; do not touch with fingers. Clamp in a vise and polish the main
surfaces with silicon carbide grains on absorbent cotton. Rub in the direction of
the long axis of the strip, carrying the stroke beyond the end of the strip before
reversing the direction (see Note 3). Clean all metal dust from the strip by
rubbing vigorously with clean pads of absorbent cotton until a fresh pad remains
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