NAVAIR 01-1A-509-3
01 March 2005
TM 1-1500-344-23-3
TO 1-1-689-3
connection displays evidence of galvanic corrosion,
c. Prevent the buildup of static potentials that could
use a washer of anodic material installed between the
result in a spark discharge.
dissimilar metals. This will cause any corrosion to
occur in the washer, the easiest and least expensive
d. Minimize static and stray currents in units
part to replace. To accomplish this, Figures 6-8 through
involved.
6-13 show the proper assembly configurations. The
corresponding material selections are shown in Tables
e. Prevent a unit from emitting electromagnetic
6-1 through 6-3. Selection of hardware material(s) and
energy that would interfere with other units and provide
order of assembly depend on the particular metal(s)
a signature for enemy detection/recognition.
specified for the structure/jumper terminal. For example,
using the configuration shown in Figure 6-8, a bolt is
f. Shield equipment from outside electromagnetic
secured as a stud through a flat structural surface. The
interference (EMI) sources.
structure is aluminum alloy and bond/ground jumper
terminal is also aluminum. This terminal maybe
6-4.2. BIMETALLIC JUNCTIONS. The connecting of
attached over a cadmiumplated steel bolt (stud) and
two or more diverse electrical objects often results in
clamped together by a cadmiumplated steel nut.
a bimetallic junction that is susceptible to galvanic
Uncoated aluminum washers are used in the position
corrosion. This type of corrosion can rapidly destroy a
as shown.
bonding connection if suitable precautions are not
observed. Aluminum alloy jumpers (bonding straps)
6-5. BONDING/GROUNDING SURFACE PREP-
are used in most bonding situations. However, copper
ARATION.
jumpers sometimes are used to bond together parts
made of stainless steel, cadmium-plated steel,
6-5.1. GENERAL. Procedures for preparation of a
aluminum, brass, or other metals. Where contact
metallic surface before mating electrical conductor(s)
between dissimilar metals cannot be avoided, the
are as follows:
choice of bonding material and associated hardware
material is important. Materials should be chosen such
that the part most prone to corrode (anode) is the
easiest and least expensive to replace. At bimetallic
junctions, where finishes are removed to provide good
Solvent, Degreasing
7
electrical connection, a protective finish/sealant shall
MIL-PRF-680
be reapplied to the completed connection to prevent
corrosion. This chapter describes and illustrates the
a. Remove all dirt, oil, and grease from a circular
procedures for the assembly and preservation of
area slightly larger than the connection. This area
bonding or grounding connections. This includes
should correspond to about 1 1/4 times the diameter of
special emphasis on techniques to minimize galvanic
the connection. Use Cloth, Non-Woven Wiping Cloths,
corrosion. Refer to Volume I for discussion on galvanic
A-A-162 Type I Class 1 or 2 (Volume IV or V, Chapter 2)
corrosion.
dampened with Degreasing Solvent, MIL-PRF-680
Type III (Volume IV or V, Chapter 2).
NOTE
b. If more vigorous soil removal is required, scrub
For additional information on bonding and
with Brush Typewriter, A-A-3077 (Volume IV or V,
grounding straps and selection of hardware,
Chapter 3), until all contaminants are removed.
refer to NAVAIR 01-1A-505, NAVAIR 01-1A-1
(Navy); TO 1-1A-14, TO 1-1A-8 (Air Force); or
c. Wipe with a dry cloth, Non-Woven Wiping Cloth,
TM 55-1500-323-24 (Army) as well as other
A-A-162 Type I Class 1 or 2 (Volume IV or V,
applicable service directives.
6-4.3. HARDWARE SELECTION. When repairing/
d. Remove paint, anodic, or conversion coating
replacing existing bonding or grounding connections,
film and surface corrosion from the planned attachment
use the same kind of attaching hardware as the original.
area with Abrasive Mat, A-A-58054 Type I (Volume IV
This hardware has been selected on the basis of
or V, Chapter 2). For corrosion beyond the surface
mechanical strength, electrical requirements, corrosion
corrosion stage, refer to Volume II of this manual
resistance, and ease of installation. When the original
(Navy and Army) or TO 1-1-691 (Air Force).
