Figure 3-29. Simplified epoxy repair.

hard-to-reach areas. In addition to cleaning the metal, it

NOTE

also etches the metal for a positive bonding surface.

d. Use air blow gun to remove any foreign particles

Leaks in aluminum radiators are most commonly

from repair. Wipe surface with a clean cloth that has been

repaired with epoxy compound. Since the work life

saturated in lacquer thinner. Before applying epoxy, the

of the prepared epoxy compound is limited, all

surface to be repaired and the small surrounding area

leaks should be exposed and repaired using one

should be thoroughly dry.

batch of epoxy compound.

e. For repairing with epoxy, an epoxy repair kit is

recommended. The kit is supplied with two separate

a. Leak test radiator (para 3-42),

tubes, one contains resin and the other hardener. For

b. If leak is in tubes, the fins surrounding leak

use, mix equal lengths (not portions) from each tube and

should be removed with duck bill pliers to facilitate

blend with mixing stick which is included. Mix until

cleaning and repairing. Remove fins to a depth of 1/4 inch

compound is a uniform grey color. The working life is

beyond leak to allow space for cleaning and applying

approximately 15 minutes, depending on room

epoxy

temperature. See Figure 3-29 for illustration of simplified

c. Clean area to be repaired. The area must be.

epoxy repair.

absolutely clean. Do not use muriatic acid. Clean with

wire brush, sandpaper or air blaster. An industrial blasting

machine will quickly and completely clean cracks and

Figure 3-29. Simplified epoxy repair.

The mixed compound can be applied with

h. Replace removed fins before curing so fins will

spatula, putty knife, mixing stick or other convenient

be bonded. Narrow strips of aluminum sheet can be used

means. When repairing a leak, apply epoxy to the repair

for replacement fins. Hand crimp the sheet with duck bill

area using a wiping and circular motion to remove any air

pliers. If care is used, the crimping will resemble the

bubbles. The epoxy compound should be applied to the

original fins.

entire area around the leak. In general, extremely thick

quantities will add nothing to the effectiveness of the

Allow epoxy to cure at room temperature for

repair.

approximately two hours. After curing, the epoxy may be

g. Holes, gaps or structural repairs may require

sanded, filed or machined.

reinforcing with glass tape, aluminum screening or other

Leak test radiator at required air pressure. Tools

approved material. When reinforcing is used, apply epoxy

compound .to both sides of the reinforcement until it is

used to apply epoxy may be cleaned with lacquer thinner,

saturated. The reinforcement should then be placed over

acetone, methyl ketone or xylene before epoxy sets up.

the repair area and covered with additional epoxy

compound. For increased strength use alternate layers of

epoxy compound and reinforcing material.

3-21