Page 23 - Shock and Vibration Overview

Equipment Setup

Figure 12: The frequency responses of different adhesives are compared which shows that the
adhesive itself has little impact on the performance.

a. Loctite or Epoxy
Loctite or a two part epoxy offers a permanent mounting option which
improves repeatability and testing time. There are many different types of
Loctite; but 454 is a popular type for accelerometer testing. Must times the
accelerometer can also be dismounting with a small shear load from the tap

of a hammer (be careful not to damage the sensor or test article though!).
Accelerometer manufacturers will recommend using a de-bonding agent like
Acetone and gently twisting the accelerometer.

b. Wax or Duct Seal Putty

Wax or duct seal putty are other popular adhesives that aren’t as effective as
Loctite or epoxy but still offer surprisingly good frequency response. The
major benefit of using this type of adhesive is that removal of the
accelerometer is much easier. Hi-Test, who does much of the shock and
vibration testing for large military systems, recommends using duct seal putty
for shock testing because it can mechanically filter out high frequency (and
thus low energy) vibration content that could risk exciting an accelerometer’s

internal resonance. Petroleum wax would have similar benefits; but note that
this can have adverse effects for an application that is interested in higher
frequency vibrations. Blanchard wax is a much stiffer adhesive and may be
preferred for these applications.

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