Cure for a Common Cold
You have been tasked with making strain measurements on a railroad bridge during the middle of a Minnesota winter. Obviously, you can’t warm the bridge sufficiently to cure adhesives for a standard bonded foil sensor installation.
There is a solution: weldable strain sensors.
A weldable strain sensor is basically a standard foil strain gage bonded to a 0.005” (0.127 mm) thick shim using M-Bond 610 adhesive. Several popular patterns are available, including uniaxial and tee-rosette configurations, in two common STC compensations, 06 and 09. To further reduce field time during those harsh winter days, pre-applied environmental protection is also available. Special Use Sensors - Weldable Strain Gages , Special Use Strain Gages - Weldable Strain Gages
The installation is simple.
- Grind away any paint or surface rust (just like any other welding operation)
- Temporarily tape the weldable sensor in place
- Use a Model 700 Welder to spot weld around the perimeter of the metal shim.
Total installation time is only a few minutes. This installation procedure is detailed in Instruction Bulletin B-131-51.
When the test program calls for temperatures above 550 °F, and where organic materials like epoxy adhesives and foil strain sensor backings oxidize and sublimate, then check out the line of high temperature weldable sensors and ceramic cements. Special Use Sensors—Weldable Strain Gages
Remember, when the installation or test environment is not amenable to the use of traditional adhesives/sensors, then weldable strain sensors may be the right solution, hot or cold.