Clamping Pressure

All M-M instruction bulletins for epoxy adhesives specify a recommended clamping pressure. Specified in pounds per square inch (psi) or kilonewtons per square metre (kN/m ² ) clamping pressure is calculated by dividing the applied force by the surface area of the rubber pad in contact with the strain gage and specimen surface. Normally the desired clamping pressure is known from the instruction bulletin, and the proposed pressure pad area can be measured. Therefore, the necessary quantity to be determined is clamping force.

As an example, the gage shown below is to be bonded with M-Bond 610 adhesive at a recommended clamping pressure of 45 psi (312 kN/m ² ). The gage pattern selected can be conveniently covered with one of the clamping pads from the M-M GT-14 pad kit. These pads measure 0.5 x 1.25 in (13 x 32 mm). The necessary clamping force can be computed by multiplying the required clamping pressure by the pad area:

Thus a 28-lb (125-N) clamping force for the example shown above would yield the recommended 45 psi (312 kN/m ² ) clamping pressure.

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