FED-STD-228A
Method 3011.1
18 APRIL 2014
BUFFING, INSULATION AND SHEATH
1. SCOPE
1.1 This method is intended for use in removing unevenness of surface from rubber and thermoplastic
insulation and jacket materials which would interfere with the measurement of thickness of the specimen
or subsequent tests. It also may be used to reduce the thickness of the piece where necessary before
testing and to remove glaze or skim coat that may interfere with further examination or tests.
2. PIECE
2.1 The piece for buffing should consist of a portion of the inspection unit of sufficient size to permit the
preparation of a specimen of the required size for test.
3. APPARATUS
3.1 The apparatus shall be as follows:
3.1.1 The apparatus shall consist of a grinder equipped with a motor-driven abrasive wheel 5 inches in
diameter, composed of approximately number 30 grit. Larger diameter wheels may be used provided the
speed is adjusted to give a surface speed equivalent to a 5-inch wheel operating at the speed specified in
4.1. The grinder shall also be equipped with a slow feed in order that very little of the material will be
removed at one cut.
4. PROCEDURE
4.1 The speed of the abrasive wheel shall be from 2,500 to 3,500 revolutions per minute if a 5-inch wheel
is used. The face of the wheel shall be sharp and the final buffed surface shall be finished uniformly and
smoothly. Very little material shall be removed at one cut, otherwise the piece may be injured by
overheating. The buffing shall not be carried beyond the point at which the unevenness of gage just
disappears, except in the case of thick materials where it is necessary to reduce the thickness for tension
or other tests. In such cases it may be desirable to slice the piece to approximately the correct thickness
of the required specimen before buffing. The specimen shall be permitted to rest at least 30 minutes
between buffing and testing.
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