Up to 4x faster measurement speed*—ideal for moving lines and swinging parts
No calibration adjustment required for most powders
Storage of 999 readings with onscreen averaging
No cable to risk disturbing the applied powder
No disadvantages – accurate, fast and easy to use
Less accurate than PosiTest
Prone to error when reading from a dial rather than digital display.
Prone to damage when dropped
Dry Film Thickness Videos
SSPC DFT PA2 Standards Explained
Measuring Paint Thickness on Steel with the PosiTest FM Magnetic Pull-Off Coating Thickness Gage
DFT Readings Made Easy By Extension Pole
How to Measure Coating Thickness using PosiTector and PosiTest Coating Thickness Gages from DeFelsko
WHY USE A DFT GAUGE?
An integral component of coating longevity is getting the correct film build. Too low a film build and you risk delamination or insufficient protection from the environment. Too high a film can compromise the bond between coating and substrate. An essential part of a coating inspectors kit is a coating thickness gauge. There is a gauge and probe combination for almost any coating over almost any substrate. Modern dry film thickness gauges not only read the coating thickness, but the more advanced models stores the test readings, analyze and interpret them and allow them to be downloaded.
COMMON ISSUES WITH COATING THICKNESS INSTRUMENTS
Coating thickness gauges range from the very simple touch and go types to sophisticated data collection tools that measure, store and analyze the readings. The advantage of the more simple units is their low cost and simple operation. Their downside is a lesser accuracy than the more sophisticated units and the lack of compliance to the full range of corrosion control standards. Conversely, the more sophisticated units provide accurate data that is in compliance with these standards and feeds into quality assurance systems. Their downside is more complicated operation which requires a higher level of proficiency.
IMPORTANT CONSIDERATIONS FOR CHOOSING THE RIGHT DFT INSTRUMENT:
Two key questions to be asked when considering purchasing a coating thickness gauge – What level of accuracy and standards compliance do I require? and How competent is the operator who will be using the gauge? Compliance to an international coating thickness standard requested by plant owner and being used by a competent and experienced operator? The DeFelsko Positest 6000 is your gauge. Just doing some quick checks for your own information or bit intimidated by anything too geeky or techish? Select the PosiTest. Another application for the PosiTest is in Hazardous Environments. As the PosiTest is an electronic device it cannot be used in a flammable or explosive atmosphere as there always is the potential for a spark.
Frequently Asked Questions
If I buy a new probe do I need to buy a new body as well?
No, the DeFelsko PosiTector 6000 system has 1 body but accepts a full range of probes. Not only coating thickness (magnetic, eddy current and ultrasonic measurement), but also surface profile, climatic monitoring, soluble chlorides contamination, infra-red temperature,ultrasonic wall thickness, hardness and gloss measurement.
What standards do coating thickness gauges conform to?
The DeFelsko PosiTector 6000 advances is compliant with the widest range of standards -ISO 2178/2360/2808, ISO 19840, ASTM B244/B499/D1186/D1400/D7091/E376/G12, BS3900-C5, SSPC-PA2, US Navy NAVSEA PPI 63101-000, US Navy NAVSEA 009-32, AS 2331.1.4, AS3894.3-B, and others. The PosiTest, ASTM D7091/B499, ISO 2808 and others.
What substrates can be measured over using a coating thickness gauge?
For ferrous (steel) substrates, a magnetic probe can be used. For non-ferrous metallic substrates, a gauge that operates on eddy currents is used. Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor. For non-metallic substrates, an ultra-sonic probe can be used.
What type of coating can be measured?
Most commonly available coating systems can be measured with a coating thickness gauge using one of the three commonly available technologies discussed above. Metallic filled coatings are not as common as previously, however should you be required to measure the thickness of one of these, a destructive test may be required. These place an angled cut in the cured coating and use trigonometry calculate the coating thickness.
What thickness of coating can be measured?
Ferrous probes can range up to 80 mils/2,000 um. Non-ferrous probes 25 mils/ 625 um. Ultrasonic probes up to 300 mils /7,600 um. Two provisos – when measuring thinner coatings use the probe with the smallest range suitable, it will be more accurate at a lower range; when measuring a thicker coating (over 60 mils/1,500 um) make sure that the probe has an upper limit greater than the target thickness on the specification. It is possible when using the wrong probe to get a measurement and not realize that it is inaccurate.