Strain Gage Installation Methods

There are basically three methods to attach a gage to a structure:

  1. Thermal Spray Attachment
  2. Ceramic Cement Bonding
  3. Weldable Gage Attachment

Thermal Spray Attachment requires direct access to the surface with the structure located in a non-hazardous non-combustible environment. The surface of the structure must be clean and prepared for bonding using either a coarse grit blasting, or by thermal spraying a special metalizing bond coat. Gages may be attached to the structure with minimal heating of the structure, usually less than 70°C (150°F).

This method is widely used for high temperature applications to attach HPI’s free filament HFN, HFP, HFK, HFH, and HFM Series wire strain gages.

The process requires a ROKIDE® Spray System that utilizes ceramic oxide rods to spray the bond coating. The rods are melted in a patented spray unit which projects the fully molten particles onto the substrate.

Rokide Spray System | Rokide Flame Spray Rods | Gage Installation Techniques

Ceramic Cement Bonding is an inexpensive, low capital investment method for installing high temperature strain gages. Grit blasing or flame spraying a special metalized precoat is required and the structure must be heated to cure the cement. Also, technicians need to be skilled in the cement application technique which requires excellent manual dexterity.

This method is widely used for high temperature applications to attach HPI’s free filament HFN, HFP, HFK, HFH, and HFM Series wire strain gages.

Ceramic Cements for Strain Gage Attachment | Application Instructions

Weldable Gage Attachment is the easiest method to attach either high temperature or waterproof strain gages to a structure. The surface must only be clean and smooth.

Weldable strain gages consist of an active sensor grid pre-bonded to a small coupon of material which is then spot welded to the structure. Gages are attached using a small portable spot welder made for strain gage work. The gages are pre-bonded in a laboratory setting under closely controlled conditions by skilled technicians, allowing for easy field installation. The gages can be pre-calibrated on a sample of structural material, so that calibration on the structure intself is not necessary.

The spot welding method can be used with all HPI’s High Temperature Weldable Series gages and Waterproof Weldable Series gages.

Installation Instructions High Temperature | Welding Instructions Video | Installation Instructions Waterproof Gages | Welding Equipment