BRAZING - TM-9-4120-428-140220

TM 9-4120-428-14

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4. Apply sufficient heat uniformity around the joint to quickly melt the filter alloy. If heat is applied slowly or on one

side, the entire component or length of tubing will be heated. The filler alloy in adjacent joints may also be melted.

Remove heat as soon as the joint is separated.

CLEANING

The entire filler alloy must be cleaned from debrazed joints before reassembly. Heat each piece of the joint until the filler

alloy is melted, then wipe it away with a wire brush. Be sure that no filler alloy or other debris is left inside any tubing,

fitting, or component.

BRAZING

1. Be sure the work area is well ventilated. Dry nitrogen should be flowing through the refrigeration system at a rate of

1 2 cfm (0.028 0.057 m3/minute). See WP 0000 00.

WARNING

The polyurethane foam, used as insulation in the air conditioner, will break down to form

toxic gasses if exposed to the flame of a torch or brazing temperature.

2. Protect the insulation, wiring harnesses, and other components with appropriate shields.

WARNING

Never use a heating torch on any part that contains refrigerant. Heat will cause the

refrigerant to break down and form carbonyl chloride (phosgene), a highly toxic and

corrosive gas. All of the refrigerant must be discharged from the system. The entire

system must be purged with dry nitrogen before beginning any debrazing operation.

NOTE

All joints, except those provided with flare fittings, are made by brazing in accordance

with MIL-B-7883. Radiographic examination is not required.

Grade IV or VI brazing alloy and Tube B flux, as specified in MIL-B-7883, must be used

for all copper to brass joints. Grade III brazing alloy may be substituted for Grade IV or

VI for copper-to-copper joints. Flux is not required for copper-to-copper joints.

3. When brazing a joint on a valve, disassemble the valve to the extent possible and wrap all but the joint with a wet

cloth (to act as a heat sink).

NOTE

If interconnected tubing was removed with a component, braze the tubing to the new

components before installation.

4. Position the component or assembly into place.

5. To quickly melt the filler alloy, apply sufficient heat evenly around the joint. If heat is applied slowly or on one side,

the entire component or length of tubing will be heated. Filler alloys in adjacent joints may also be melted. Remove

heat as soon as brazing is completed.

NOTE

FOLLOW-ON MAINTENANCE:

Remove service manifold (WP 0064 00)

END OF WORK PACKAGE

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