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TM 10-4130-239-14
5-5.
REFRIGERATION SYSTEM SERVICE - BRAZING/DEBRAZING (CONT)
c.
d.
e.
Parts shall be preheated with a neutral or slightly reduced
flame to bring the entire joint uniformly to the liquid
temperature of the filler metal.
Use only as much heat as
needed to provide a satisfactory joint.
Avoid localized
overheating.
Keep moving the flame in small arcs or figure
eights.
Most of the heat should go to the joint where the
filler material is to flow.
Introduce filler material at the opposite side from the flame.
Use capillary action to fill the joint while feeding the
filler material.
Do NOT use the flame to melt the filler
material.
If the filler material will not melt when brought
in contact with the joint, then the joint is not clean or hot
enough.
Use a wet rag to wipe the joint clean of flux residue.
Inspect completed joint for the following:
1.
2.
3.
4.
5.
The contour of an outside filler joint shall be of a uniform
radius with minimum excess filler material.
Examine joint for pinholes.
A pinhole is a defect caused by
gases being expelled.
It appears as a small, round, smooth-
surfaced pocket on the surface of the filler material.
Do not
permit pinholes in any joint.
Inspect for any residual flux on the surface of a brazed joint.
Clean of necessary.
Brazing filler material in excess of that required for the joint
is acceptable providing the excess filler metal does not interfere
with the function of the completed assembly.
When possible, inspect inside the joint for filler material
penetration.
Filler must appear at all edges of a joint to prove
proper flow through the joint.
Lack of penetration shall be cause
for rejection of the joint.
5-11
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