Testex Press-O-Film Tape consists of foam with a non-compressible backing. The foam side is rubbed into the surface providing a permanent mould of the peak-to-valley profile, which can then be measured using the Elcometer 124 Thickness Gauge.
Testex Press-O-Film Tape is available in three profile ranges. It is important that the tape grade chosen is reflective of the profile being measured, as using tape grade below the actual value may provide a "false" reading.
Runs & Sags: Coatings move under gravity leaving a thin dry film.
Cissing: When a coating does not re-flow to cover the voids generated by air bubbles being released from the surface of a coating.
Cratering: If the substrate is wet or the coating has poor flow characteristics, voids are created in the coating.
Pinholes: Caused by air entrapment which is then released from the surface, or by the entrapment of particulates (dust, sand etc.) which do not stay in place.
Over Coating: If too much coating is applied, as it cures internal stresses of the coating can cause it to crack.
Under Coating: Un-coated areas, or where the coating flows away from edges or corners of a substrate or welds. Insufficient coating over a rough surface profile may also leave the peaks of the profile exposed.
Testex Press-O-Film Tape consists of foam with a non-compressible backing. The foam side is rubbed into the surface providing a permanent mould of the peak-to-valley profile, which can then be measured using the Elcometer 124 Thickness Gauge.
Testex Press-O-Film Tape is available in three profile ranges. It is important that the tape grade chosen is reflective of the profile being measured, as using tape grade below the actual value may provide a "false" reading.
The Elcometer 124 Thickness Gauge is used to measure the peak-to-valley height of a surface profile moulded in the Testex Press-O-Film Replica Tape.
Key benefits and features of the Elcometer 124 Thickness Gauge include:
Available in both Metric and Imperial versions
Quick and easy to use
Anvil pressure as required in the Standards
Reproducibility (ASTM): ASTM standard D 4417-03 cites levels of reproducibility for both "X-Coarse" and "Coarse" grade replica tape. (A revision, with precision and bias data appropriate to Press-O-Film HT, is in development and will likely become available in early 2012. Preliminary results suggest that the associated, newer, testing will indicate that replica tape has much smaller levels of error than is reflected in the numbers below.)
For X-Coarse grade replica tape:
"Two results, each the mean of four replicates, obtained by operators in different laboratories should be considered suspect if they differ by more than 37%." For Coarse grade replica tape, the equivalent level of reproducibility is cited as 28%. According to these ASTM criteria, the following errors are the maximum that should be expected(according to the current version of the standard):
PROFILE (mils) (microns)
ERROR ("COARSE") (mils) (microns)
ERROR ("X-COARSE") (mils) (microns)
1.0 / 25
0.3 / 8
not applicable
2.0 / 50
not applicable
0.8 / 18
3.0 / 75
not applicable
1.1 / 27
4.0 / 100
not applicable
1.5 / 37
Accuracy (NACE): NACE Standard RP0287-95 addresses the issue of accuracy of measurement, reporting the results of round robin tests in which 14 blasted panels were measured by 7 laboratories. Replica tape and focusing microscope measurements agreed within their 95% confidence limits in 11 of 14 cases. The average difference between the two types of measurement was 0.2 mils (5 microns).
