Printed Wiring Assemblies (PWAs)
Staking compound negating stress relief

The white arrow in figure 2 points to a fractured solder connection caused by insufficient stress relief. The red arrow points to staking material that was applied directly over the change of direction of the wire where the stress relief was originally provided.

Reference :
NASA-STD-8739.1, paragraph 9.2-3a:
The staking compound does not negate stress relief of parts and enclose joints, part leads, or mechanically compromise the reliability of the hardware.

NASA-STD-8739.3, paragraph 8.1-1:
Stress relief shall be incorporated, wherever possible, into all leads and conductors terminating in solder connections to provide freedom of movement of part leads or conductors between points of constraint. Leads shall not be temporarily constrained against spring-back force during solder solidification so that the joint is subject to residual stress. Examples of stress relief are shown in figures throughout this chapter.