Glues, connective are applied for fixing of strain gauges on the investigated surface must answer the next basic requirements:
À) to Provide the transmission of deformation of investigated surface to the strain gauges and as possible less creep of testimonies in the working range of temperatures and deformations. A creep is conditioned by plasticity of glue.
B) to Provide electro- isolation of strain gauges from the investigated surface
As a rule the suppliers of strain gauges drive to documentations the list of glues with optimal descriptions for this type of strain gauges and technology of their application.
Short descriptions over of glues are below brought most often used in tensometry.
For foil strain gauges:
Glue of superglue EO. It is glues of cold hot-settings, quickly grabbed. Used for agglutination of unporous materials and metals. Without application of efforts of compression harden during 48 hours. Worker range of temperatures - 80 - +80 °C.
Glue of UVS-10Ò. Hot curing, onecomponent. Connects non-metal unporous materials and metals. Working range of temperatures - 70 - +200°Ñ. Polymerization (hot-setting) of glue is carried out as follows: to survive the glued strain gauges 0,5 hour at normal terms. Further to survive 5 hours at a temperature 180 °C pressure of pinning 0,1 - 0,3 ÌPà (1 - 3 atm) in the conditions of thermo closet. Then at a temperature 215 °C in the conditions of open polymerization to survive 5 hours.
Glue of BFR-2Ê. Behaves to onecomponent glues of hot hot-settings, phenol-formaldehyde. Terms of polymerization, technology of the use analogical to glue of UVS-10Ò.
In addition, for example, most often recommend glues of superglue EO for the strain gauges of 2FKPA, 2FKPD, FK-PA of and other. For the strain gauges of 1FKTK and 2FKTK glues of BF- 2, VL- 9. Varnish of VL- 931 for the strain gauges of 2FKNA, 2FKPD, 2FKRB and other
A table (N.P.Klokova. Strain gauges. Ì., 1990) is below presented from descriptions some other glues.
For the manufacture of strain gauges are used depending on the operating conditions for the hot glue rejection, BF, VS-10T, VL-931 etc.; modified rubber; such as VC-32-20, VC-13, etc.
The most widely used for the installation of strain gages used epoxy glues cold rejection. ??? additionne and have high mechanical performance, allow to measure large strains, admit the overload, long-term cyclic loads of up to 100 million cycles. These characteristics are saved at multicyclic loads.
Adhesives hot rejection are used for installation of strain gauges in the case study sample and design elements that allow thermal processing as well as when using the strain gages as intermediate converters in the measuring devices. To the strain gages had a satisfactory measuring characteristics (linearity transformation, small values of creep and hysteresis, etc.). The temperature of the heat treatment of the strain gages after installation should be above the temperature of polymerization of adhesives specified by razrabotchikom. So the use of phenol-formaldehyde adhesives modified with polyvinylacetate having a curing temperature of 140 °C, the strain gages provide satisfactory creep only after two hours of heating at t=200-250 °C, metal foil strain gages with a binder of glue fenolovogo VK-32-200M have satisfactory stability characteristics of the sensitivity in the temperature range 20-200 °C only after heat treatment at 230 °C.