Adhesive-Backed Strain Gages
The majority of foil strain gages are installed using an adhesive system that is purchased separately from the strain gage itself. On some Micro-Measurements gage types it is possible to order the gages with a B-staged epoxy adhesive already applied to the gage backing. B-staged adhesives are a family of adhesives that when initially applied are dry to the touch, but can be re-liquefied and fully cured through exposure to heat and pressure.
How do you use it them? Gages ordered with B-staged adhesive are shipped in special non-contaminating flat trays. To install the gages you simply remove them from the trays, place them at the desired bonding location, and hold them temporarily with a small piece of MJG-2 tape. Then apply normal bonding pressure and oven-cure. No additional adhesive is needed.
Advantages/disadvantages: The biggest advantage is in not having to purchase, mix, apply, and store a separate adhesive for gage bonding. The biggest disadvantages are dealing with gages that now have a shelf life (approximately six months under lab conditions) and needing to use tape to hold them during cure.
Availability: Two conditions must be met. First the gages must be film-backed (Micro-Measurements series, N2A, J2A, N2K, J2K, and J5K), and the gages must be small enough to fit into the flat trays.
Operating temperature range: -452°F to +250°F (-269°C to +120°C)