1. PREPARE SHAFT SURFACE:
- Remove paint and other coatings; degrease as necessary.
- Rough sand with 220 grit paper then polish with 400 grit paper.
- Finish sanding with 400 grit paper and M-Prep Conditioner.
- Rinse with M-Prep Conditioner.
- Rinse with M-Prep Neutralizer and wipe dry.
2. MARK SHAFT SURFACE FOR STRAIN GAGE ORIENTATION AND ALIGNMENT.
- The strain gage should be installed flat and square to the axis of the shaft. For a straight reference line square to the axis, wrap a piece of paper around the shaft, align the edges and then mark or etch the straight reference line onto the shaft.
3. PREPARE STRAIN GAGE FOR MOUNTING.
- Part # CEA-06-250US-350 is a common torque-pattern strain gage.
- Remove strain gage from package.
- Apply cellophane tape to top side of gage. Use the tape as a “handle.”
4. POSITION STRAIN GAGE BEFORE GLUING:
- Tape gage in place on the shaft using reference marks on shaft and gage for alignment.
- Lift one end of tape and “hinge” back to expose bottom of gage.
- Apply an even, thin layer of catalyst to bottom side of gage and let dry.
5. GLUE STRAIN GAGE TO SURFACE:
- With the gage/tape still hinged back, apply bead of M-Bond 200 Adhesive where the tape meets the shaft surface. (M-Bond 200 is a special Cyanoacrylate which has been pretested and certified for use in bonding strain gages – manufactured by Vishay Measurements Group.)
- Using Teflon film or equivalent as a non-stick barrier between your thumb and the adhesive, press the gage/tape to shaft surface with single rolling/wiping motion of the thumb.
- Apply thumb pressure for one minute, followed by a minimum two-minute wait before removing the cellophane tape. Bond strength increases rapidly during first five minutes.
6. ATTACH LEAD WIRES AND PROTECT STRAIN GAGE:
- Discard Teflon film and carefully peel back cellophane tape from the strain gage.
- Tin with solder the solder pads of the strain gage plus the lead wires. Attach lead wires to solder pads.
- Clean solder joints with rosin solvent.
- For waterproofing – Apply polyurethane coating to strain gage and solder joints.
- For mechanical protection – Cover the gage with butyl rubber or equivalent.
- For electrical shielding – Cover the strain gage and lead wires with aluminum tape or equivalent.
- M-Coat J from Vishay Measurements Group is a two-part polysulfide liquid polymer compound for environmental protection of strain gage installations. When fully cured, it forms a hard rubber-like covering that provides an effective barrier against water and many other fluids. The tough coating also protects installations from mechanical damage.
7. STRAIN GAGE WIRING DIAGRAM: