Strain-Gage-Adhesives

Supported Applications

The Omega Cold-Curing Strain-Gage Adhesive series (models SG401 and SG496) consists of solvent-free cyanide-acrylate adhesives developed for applying bonded-resistance strain gauges. These rapid-cure formulations are suitable for all series of strain gauges and compatible with most metals of common use as well as most synthetic materials.

The adhesive is not suitable for porous materials such as concrete, wood, or foam plastic.

Operating Conditions & Performance

Polymerization performance depends on environmental humidity. Relative humidity (RH) between 40% and 70% is most favorable; RH less than 30% retards or stops the reaction, while more than 80% RH causes shock setting.

Setting speed varies by substrate material:

• Steel: 60 to 120 sec.
• Aluminum: 50 to 100 sec.
• Plastics: 10 to 60 sec.

Curing times for measurement depend on the type of measurement and ambient temperature. At 20°C (68°F), minimum curing time is 10 min. for dynamic measurements and 15 min. for static measurements. At 5°C (41°F), these periods extend to 90 min. and 120 min., respectively.

Ultimate curing is achieved after some 24 hours, though measurements can be taken after the minimum times listed above. The thickness of the adhesive film in a correctly adhered gauge is 8 micrometers ± 20%.

Influencing Factors

Setting speed depends on the chemical condition of components to be bonded. Alkaline materials accelerate polymerization, whereas acid materials can retard or completely prevent setting; a neutralizer should be used in acidic cases if a very thin adhesive layer is guaranteed.

Configuration Options

The series supports two package sizes:

• SG401: 0.10 oz. net weight.
• SG496: 1.00 oz. net weight.

The adhesives are supplied as modified versions of a solvent-free cyanide-acrylate adhesive. Complete setting in the given time is achieved only with thin films; thick layers set very slowly and incompletely, making extremely rough contact surfaces unsuitable.

Key Product Differences

The primary distinction between variants is net weight packaging (SG401 vs. SG496). Both models utilize the same solvent-free cyanide-acrylate chemistry with identical setting and curing characteristics relative to substrate material, temperature, and humidity.