Which method helps identify voids in plywood panels?

• A. Inspect sheets and test for voids with light or tapping.
• B. Store panels in direct sunlight to dry them.
• C. Use water to identify delamination.
• D. Sand the surface to detect voids.

Answer: (B)

Voids are internal gaps between the plies of plywood that can weaken the panel and affect its performance. The most effective way to identify them is to perform a non-destructive check using light and sound.

Shining a bright light through the sheet helps reveal voids because gaps or weak glue lines will show up as dark spots or irregular glow when viewed from behind and along the edges. Move the light slowly across the panel and inspect both sides and the edges.

Tapping the panel provides an acoustic cue. When you tap a solid area, the sound is crisp; a void or hollow area produces a duller, more muffled tone. Compare various spots across the sheet, including near seams or where glue lines run, since voids often occur there.

These methods directly target the internal structure and are far more reliable for detecting voids than drying panels in sunlight, using water to test for delamination, or sanding the surface, which only reveals surface or near-surface issues and won’t reliably show hidden gaps.