Installing Strain Gages on Fiberglass
Fiberglass is used as a structural material, and it is found all around us in such things as automotive bodies, boat hulls, sports equipment, utility enclosures, etc. Installing strain gages on fiberglass laminates is a fairly straightforward process as long as the correct steps are followed:
- Select a strain gage with an active grid length of sufficient length to span 3-5 repetitions of the fiber. Typically, a resistance of 350 or 1000 ohms is preferred since fiberglass is a poor heat sink and the higher resistance helps reduce self-heating, thus improving zero stability.
- Degrease the surface with GC-6 Isopropyl Alcohol.
- Lightly abrade the surface with 400-grit Silicon Carbide Paper, just enough to remove all surface gloss. Do not abrade too far as it is important not to damage the glass fibers; this would reduce structural strength.
- Mark the gage location. Avoid surface contamination and damage.
- Scrub with Micro-Measurements Conditioner A and then wipe dry.
- Scrub with Micro-Measurements Neutralizer 5A and then wipe dry.
- Bond the gage with Micro-Measurements M-Bond 200 or AE-10 adhesive
- Install leadwires
- Apply appropriate protective coating