Adhesives, Sealants & Industrial Bonding worked example

Lap Shear Strength Estimate at 63% surface-prep effectiveness: a worked example

This worked example runs the lap shear strength estimate numbers for a tougher week than the baseline: 63% surface-prep effectiveness instead of the typical 88%. Estimate effective lap shear load capacity from overlap area, adhesive shear strength, surface-prep effectiveness, and cure yield.

The inputs for this scenario

  • Lap overlap area: 2.5 in² or mm² (held at the documented default)
  • Adhesive shear strength: 2,800 psi or MPa (held at the documented default)
  • Surface-prep effectiveness: 63 % (the input this scenario stresses; the baseline uses 88)
  • Cure/process yield: 92 % (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Theoretical lap shear capacity = lap overlap area × adhesive shear strength.
  • Effective lap shear capacity works out to 4,057 lbf or N at these inputs, and this is the headline figure for the scenario.
  • Theoretical lap shear capacity works out to 7,000 lbf or N at these inputs.
  • Surface-prep loss works out to 2,590 lbf or N at these inputs.
  • Cure/process loss works out to 353 lbf or N at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where surface-prep effectiveness sits at 88% and the headline result is 5,667 lbf or N, this scenario comes in 28.41% below the baseline at 4,057 lbf or N.
  • Use it for early joint sizing, adhesive candidate screening, or setting a realistic proof-load target before physical pull testing. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Effective lap shear capacity: 4,057 lbf or N (headline result)
  • Theoretical lap shear capacity: 7,000 lbf or N
  • Surface-prep loss: 2,590 lbf or N
  • Cure/process loss: 353 lbf or N

Run it with your numbers

  • To rerun this with your own numbers, open the live Lap Shear Strength Estimate calculator, set surface-prep effectiveness to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.