Bonding A Strain Gauge with Pre-Attached Leadwires

For those you who hate to solder or your application demands preattached leads Micro-Measurements offers several options. C2A series gages, CEA W/Option P2 and EA W/Option P all have 10 feet of leadwire pre-attached; however, when using these leaded gages some special techniques should can be used to insure successful installations.   For more detail, please view Micro-Measurements Tech Tips VMM-9 and VMM-10.

In the following example we will bond a C2A series gage using our M-Bond 200 adhesive (typical of leaded gages)

After surface preparation appropriate for the material and alignment marks applied the test part, the gage is laid out onto a glass plate then transferred to the part.  

The PCT-2M ( or PCT-3M) gage handling tape is placed transverse to the long axis of the gage/leadwire . Further we recommend taping the bundle of leadwire to the part on test prior to bonding. This will help to avoid damaging the uninstalled or recently installed gage if you were to drop the leadwire bundle; especially if the gage is to be bonded to a vertical surface.

After the gage is properly aligned, peel up the gage handling tape at a shallow angle exposing the bonding surface of the gage. Apply the Catalyst C to the gage backing with a single wiping motion with the side of the brush cap applicator (like a squeegee). Allow it to air dry for at least 1 minute.

Apply the drop of M-Bond 200 at the tape/part interface. Using a gauze sponge wipe the tape back down into position. Hold thumb pressure for 1 full minute. Wait for 2 minutes with the tape still in place for the 200 to fully cure.

Carefully pull the gage handling tape 180° back over its self being sure not to damage the gage leadwire interface. Rosin solvent can be used to break down the tape mastic to help limit the force applied to the leadwire thus limiting the potential for damage to the leadwires. Finally, apply the appropriate environmental protection commensurate with the test conditions.


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Yuval Hernik

StrainBlog Editor in Chief