Leadwire Selection

Ideally, the smallest practicable diameter leadwire should be soldered to the gage to reduce solder connection height and its effect on uniform clamping pressure. This is not without limitation since the smaller the leadwire the greater its resistance and corresponding effect on circuit stability and sensitivity.

As a general guideline, no larger than stranded 30 AWG wire, 0.031 in (0.8 mm) overall diameter including insulation, should be used with the 100%-solids epoxy adhesives. These include M-Bond AE-10 , AE- 15 , GA-2 , and GA-61 adhesives.

With solvent-thinned adhesives such as M-Bond 43-B , 600 , and 610 , attainment of uniform clamping pressures is more critical. The maximum recommended leadwire diameter for these adhesives is 0.01 in (0.25 mm) including insulation. Leadwire types with film insulation, such as 130-AWN or 134-AWP are preferred.

Cyanoacrylate adhesives, such as M-Bond 200 , present difficulties in adhesive application and clamping due to their quick-setting nature, and are seldom used for gages with preattached leadwires.

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