Testex Press-O-Film Replica Tape consists of a layer of compressible foam affixed to an incompressible polyester substrate of highly uniform thickness. When pressed against a roughened steel surface, the foam collapses and forms an impression of the surface. Placing the compressed Testex tape between the anvils of a micrometer thickness gage and subtracting the thickness of the incompressible substrate gives a measure of the surface profile.
Each roll of Testex Tape includes 50 pieces (impressions).
Testex Press-O-Film replica tape is available in a variety of thickness ranges for measuring substrate roughness. The primary range for measurement with replica tape is 20 to 115 µm (0.8 to 4.5 mils). Use of Coarse Minus grade (<20 µm or <0.8 mil) or X-Coarse Plus grade tape (>115 µm or >4.5 mils) should primarily be restricted to checking measurements at the lower and upper ends of the primary range.
Testex Press-O-Film Optical Grade replica tape, when used with PosiTector RTR 3D models, provides higher quality surface data files (.SDF) than conventional replica tape. Optical Grade Replica Tape is available in Coarse or X-Coarse.
A variety of micrometer thickness gages are available for measuring blast steel profile using Replica Tape. Select from dial thickness gages (snap gages) and digital replica tape readers.
Testex Micrometer Dial Thickness Gages measure the surface roughness of blast cleaned surfaces. They are the only gages specifically designed for use with replica tape having the correct accuracy, closing force, anvil/contact point dimensions, and parallelism specifications required for accurate measurement of replica tape.
Includes choice of snap gage, plastic burnishing tool, instructions, carrying case, and one (1) year warranty.
Replica tape readers, such as the PosiTector RTR H and PosiTector RTR 3D, use Testex Press-O-Film replica tape to measure and record surface profile parameters.
All gages come complete with stainless steel burnishing tool, 5 cleaning cards, check shim(s), surface cleaning putty, protective rubber holster, wrist strap, 3 AAA alkaline batteries, instructions, nylon carrying case with shoulder strap, protective lens shield, Long Form Certificate of Calibration traceable to PTB, USB cable, PosiSoft Software, two (2) year warranty on body and probe.
Digital spring micrometers measure and record surface profile parameters using Testex Press-O-Film replica tape—producing a more accurate peak-to-valley surface profile height measurement for blasted steel and textured coatings.
Digital replica tape imagers measure and record peak height, peak density, and 14 common 2D/3D surface profile parameters (Ra, Rq, Rz, Rp, Rv, Rt, Rpc [2D], and Sa, Sq, Sz, Sp, Sv, and Spd [3D]) using Testex Press-O-Film™ replica tape. Download high resolution .SDF files for further analysis (Advanced models only).
Testex Micrometer Dial Thickness Gage Kits include everything required to measure the surface profile using replica tape. Includes choice of snap gage, two rolls of Testex Press-O-Film tape (Coarse and X-Coarse), training surface of known roughness, burnishing tool, and complete instructions.
Clean the surface with a putty to remove dust and other contaminants.
Use cleaning putty to remove dust, debris, or residual blast media from the measurement site by firmly pressing the putty onto the surface to be tested using your fingers and remove.
Select the appropriate grade of replica tape, then pull a single piece of tape free of its release paper and apply to blasted surface.
Firmly compress replica film using burnishing tool by applying sufficient pressure in a circular and x-y rubbing motion. When complete, remove tape from surface.
Insert the compressed replica tape between the micrometer's measurement anvils and take a reading.
Ensure the tape is properly positioned so that the burnished region is centered in the anvils with the adhesive side down.
Testex Press-O-Film replica tape consists of a layer of crushable plastic microfoam coated onto polyester film of highly uniform thickness. It is sold in a number of grades to accommodate measurements in different profile ranges.
Testex Press-O-Film HT is an improved version of Press-O-Film (discontinued in 2010). Press-O-Film HT (High Temperature) is formulated for better performance at high temperatures (up to 140°F or 60° C) encountered in the most challenging environments.
Replica tape consists of a layer of compressible foam affixed to an incompressible polyester substrate. When pressed against a roughened (steel) surface, the foam collapses acquiring an impression of the surface. Placing the compressed tape between the anvils of a micrometric thickness gage, and subtracting the contribution of the incompressible substrate (50 µm or 2 mils), gives a measure of the surface profile. Consequently, the thickness of the compressed tape equals the average maximum peak-to-valley profile plus the thickness of the incompressible polyester substrate. A spring-loaded micrometer gage is used to measure the thickness of the replica.
There are multiple ways of expressing the accuracy or precision of an instrument or test method. The most common method in our industry is to measure on traceable standards in a calibration laboratory. This is challenging for surface profile measurement instruments because no traceable surface profile standards exist. For some instruments, such as depth micrometers (ASTM D4417 Method B), accuracy can be estimated using calibrated height standards. For replica tape, the ASTM D01.46 committee used a set of panels blasted with a range of surface profiles, and compared the results from replica tape against measurements taken on the same panels using a calibrated drag stylus micrometer (ASTM D4417 Method D). Across the 0.8-4.5 mil (20-115 micron) primary range of replica tape, the readings differed by less than ± 0.3 mils (± 9 microns), as summarized in the table below.
However, this tests the accuracy of the instrument or apparatus, but not necessarily the overall test method. For most users, it is more important that measurements are consistent between the various parties (for example, the specifier or contract author, the contractor, and the inspector). Because blasted surfaces are complex, random shapes, the ability of an instrument to measure height in a laboratory is not necessarily indicative of its ability to measure surface profile in a consistent, repeatable manner in the field.
In 2011 the ASTM D01.46 committee preformed an interlaboratory study, which measured the reproducibility of measurements made by multiple users and laboratories (stated as the range that 95% of measurements from all operators across all laboratories fall within). The results are summarized as follows:
The accuracy/reproducibility values are specified at 3 mils in the above table, and typically vary across the range of an instrument. For Replica Tape:
In summary, independent studies have shown that Testex Press-O-Film replica tape is a highly accurate measurement method with industry-leading reproducibility.
Industrial steel in bridges, ships, railcars, etc., is almost always painted or otherwise coated to prevent corrosion. Before they can be painted, these metal surfaces must be cleaned and roughened to ensure that the paint adheres. This is usually done by grit or shot blasting the surface. If the resulting surface is too smooth, the paint or coating will not stick. If the surface is too rough, the peaks may poke through the coating allowing rusting to occur.
Most international standards instruct users of replica tape to take two replica tape readings in each measurement area, and average those two readings together to yield a 'Profile Measurement'. As with any test, averaging multiple measurements improves repeatability and accuracy.
If a measurement made with either Coarse or X-Coarse replica tape in the 'overlap range' of 38 to 64 µm (1.5 to 2.5 mils), a second measurement should be taken in the same spot with the other grade of tape. If BOTH readings are in the above Overlap Range, record the average of the two measurements as the peak-to-valley roughness. If EITHER reading is outside of the Overlap Range, record it as the profile height.
For more information, consult the Testex Press-O-Film Replica Tape Instruction manual.
Round-end plastic rubbing tool to compress replica film on the blasted surface
Contains a pattern with a known peak-to-valley profile height, to learn and verify correct measurement technique
Used to verify the accuracy and operation of Testex and other spring micrometer replica tape readers