The first strain gage used by Dr. Arthur Ruge at MIT was made of wire, cigarette paper, and bonded with Duco Cement. While the technology has advanced a long way, the base principles have not changed. An intimate bond with a substrate transfers in-plane strain to the sensing foil of the gage which causes the gage resistance to change. Without proper bonding, a gage may come entirely detached from the part, or worse, give unreliable data. The first step to any strain gage application will be preparing the surface appropriately before applying adhesives and protective coatings. Following best practices, the success of strain gage applications will be much higher, and you can have faith in the data which is generated.
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