When bonding Micro-Measurements Advanced Sensors Technology strain gage sensors (CEA, C4A, C5K) you want to ensure an excellent bond. The key element in bonding strain gages is surface preparation.
The video above demonstrates specific procedures and techniques with proven advantages. By precisely following these carefully developed instructions (along with the requisite procedures for gage and adhesive handling), the result will be strong and stable bonds. This video presents a procedure that is simple to learn, easy to perform, and reproducible. Keep in mind, it is very important to pay attention to detail and follow the instructions precisely. The importance of surface preparation for strain gage bonding cannot be understated.
1) Degreasing
Rigorously degrease the gaging area with a good solvent, such as CSM Degreaser or GC-6 Isopropyl Alcohol. Be aware though that some materials (e.g., titanium and many plastics) react with strong solvents. Make sure your solvents do not contain any contaminants2) Abrading
Preliminary dry abrading with 220 or 320-grit silicon-carbide paper is generally required if there is any surface scale or oxide. Final abrading is done by using 320-grit silicon-carbide paper on surfaces thoroughly wetted with M-Prep Conditioner A; this is followed by wiping dry with a gauze sponge. Repeat this wet abrading process with 400-grit silicon-carbide paper, then dry by slowly wiping through with a gauze sponge. Finish with 320 grit on most steels and 400 grit on aluminum alloys.3) Burnishing of Layout Lines
Using a 4H pencil (on aluminum) or a ballpoint pen (on steel), burnish (do not scribe) whatever alignment marks are needed on the specimen.4) Conditioning
Repeatedly apply M-Prep Conditioner A and scrub with cotton-tipped applicators until a clean tip is no longer discolored. Remove all residue and Conditioner by again slowly wiping through with a gauze sponge. Never allow any solution to dry on the surface because this invariably leaves a contaminating film and reduces chances of a good bond.5) Neutralizing
Now apply a liberal amount of M-Prep Neutralizer 5A and scrub with a cotton-tipped applicator. With a single, slow wiping motion of a gauze sponge starting within the clean area and wiping outward in one direction. Repeat the wiping step with a clean gauze pad, again, start in the clean area, wipe though the gage location moving outward in a single stroke to fully dry this surface. Do not wipe back and forth because this may allow contaminants to be redeposited.For proper outcomes, the procedures and techniques presented here should be used with qualified installation accessory products from Micro-Measurements, namely:
- CSM Degreaser or GC-6 Isopropyl Alcohol
- Silicon Carbide Paper
- M-Prep Conditioner A
- M-Prep Neutralizer 5A
- GSP-1 Gauze Sponges
- CSP-1 Cotton Applicators
- PCT Gage Installation Tape