Plastics are avaialble in many kinds and common in low elasticity, low heat-conductivity and large linear expansion coefficient. For plastics, GF series gauges are used. In strain measurement of low elastic materials, the thinner the specimen's thickness, the smaller the srain sensitivity apparently becomes. This phenomenon is called strain gauge stiffening effect, and the smaller the elastic modulus of specimen, the larger the stiffening effect is, and also the thinner the specimen is, the larger the effect becomes.

A special turn-tab with looped ends to easily get sensitivity to low elastic materials is adopted for the gauge grid. The sensing grid is aligned to minimize the influence of Joule's heat.

In general, plastic materials such as fluorinated resin, polyethylene and polypropylene can not be adhesive-bonded. However, special chemical treatment makes bonding possible. As the adhesive is CN only, the test temperature range is restricted to the operating temperature range of the CN adheisve.

Treatment with the following chemicals makes bonding with CN ahdesive possible.