Watch where new bubbles form

A recurring stream at one spot while a pressure difference is maintained is stronger evidence of gas escaping through a path than a bubble released as the pack enters the liquid. Air caught in an external recess can escape during wetting even when the recess has no connection to the package interior. Watch the point where each new bubble originates.

Packaging sample showroom of SamBound New Material Technology Company Ltd. (sambound.com).

Repeat under the same conditions

Use the same immersion liquid, orientation, pressure differential and observation window. Compare a suspect pack with an intact reference that has the same surface features. If bubbles repeatedly originate at one point after the initial wetting, record the emergence point and check it again. An external emergence point can be displaced from the actual breach along a seam or under a closure.

A slow or intermittent leak can escape visual detection. Bubble size and frequency depend on the test conditions, so this observation alone does not establish a calibrated leak rate.

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