Testex Tape

Testex Tape

Testex Press-O-Film replica tape is available in a variety of thicknesses to facilitate profile measurement in differing ranges.

The primary range for measurement with replica tape is 0.8 to 4.5mm (20 to 115µm). Use of Coarse Minus grade (<0.8mm or <20µm)

Testex replica tape can be used with a gauge to measure the surface roughness (“profile”) of blast-cleaned steel in the roughness range 0.8 to 4.5mm (or 20 to 115 micrometers). Because inspectors, as a rule, have a target profile in mind. it is always best to start measurements with the grade of tape that has the target profile closest to the centre of it’s range.

Our Instructions webpage details the averaging procedure used in the overlap region between Coarse and X-Coarse grades.

Testex lowest grade (thinnest) tape, Coarse Minus, should be used only to check measurements at the lower end of the next higher grade, Coarse.

Firmly compress tape with the smoothest surface on the rubbing tool provided, applying sufficient pressure to produce a replica with a uniform pebble grain appearance. You should feel the roughness as you burnish.

Fine/Medium grade material is commonly used in applications in which the replica is analysed using precision laboratory techniques. This grade is not suitable for use with a “dial thickness gauge. Fine grade tape (rarely used) has a thin Gold coating to facilitate electron microscopy. Medium grade tape has a thin Indium coating to facilitate optical interferometric measurement. Fine and Medium grades have the same foam thickness. Only the vapor-deposited metallic coatings differ. “Unmetallized” Medium grade tape is also available without any metallic coating.

All grades are coated onto a tough polyester substrate 2.0 mils (50 um) in thickness.

Because implicit definitions of “roughness” vary between methods, numerical profiles determined using different techniques (replica tape, interferometer, confocal microscope, analog stylus, digital stylus) may yield different values. Always specify the technique used.

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