Resources
DONGRU app
Connect your DONGRU instruments, capture readings and generate reports straight from your phone.
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Industry Applications
Powder Coating Thickness on Steel and Aluminum: A Field Guide
Choose magnetic induction for suitable steel and eddy current for aluminum; verify on a matching bare substrate before measuring cured powder coating.
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Measurement Methods
Measurement Records and Inspection Reports: A Field Template
Record the method, gauge checks, locations, readings and acceptance rule in a coating-thickness report so another inspector can verify the decision.
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Measurement Methods
Ultrasonic Measurement: Coupling and Probe Technique Done Right
Ultrasonic thickness readings depend heavily on coupling: pick the couplant for the job, use the right amount, spread it evenly; keep the probe perpendicular,…
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Measurement Methods
Temperature, Humidity and Cure State: Environmental Factors That Move the Reading
Ambient temperature affects the gauge electronics and the coating state, humidity affects surface coupling and the sound speed in substrates like concrete, and the…
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Measurement Methods
Correcting Measurements on Rough Surfaces: From Measurement to Acceptance
Rough surfaces (blast-cleaned steel, hot-dip galvanising, concrete) make readings read systematically high; the correction is to first measure the base metal reading on uncoated…
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Measurement Methods
Measuring on Curved, Small and Edge-Adjacent Surfaces: Special-Geometry Techniques
Errors on curved, small and edge surfaces come from incomplete contact geometry: convex reads high, concave reads low, edges read unstable; countermeasures include a…
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Measurement Methods
Calibration Shim Verification: Correct Practice and 5 Common Mistakes
Shim verification is the every-shift action required by ASTM D7091-22: place a shim of known thickness on bare substrate, and the reading versus nominal…
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Measurement Methods
Spot and Area Measurement: The SSPC-PA 2 Sampling Logic, From Point to Zone
SSPC-PA 2-2022 uses a two-level sampling plan: spot measurement (the average of no fewer than 3 readings within a roughly 1.5-inch diameter circle) and…
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Measurement Methods
Base Metal Reading (BMR) and Zero Adjustment: Blast-Cleaned Steel and Irregular Parts
The base metal reading (BMR) is the "false thickness" measured on bare substrate, coming from surface roughness, substrate material and geometric curvature; both SSPC-PA…
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Measurement Methods
Calibration, Verification and Adjustment: Keep the Three Operations Separate
ASTM D7091-22 breaks gauge use into three steps: Calibration (done once by the manufacturer or a lab), Verification (performed by the operator every shift),…
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Instrument Selection
Accessories and Consumables List: Probe, Reference Shim, Couplant and Test Block
The completeness of a thickness-measurement system relies on four classes of accessories: the probe (replaceable and wear part), the reference shim (runs per-shift verification),…
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Instrument Selection
10 Questions You Must Ask Before Buying an Instrument
Before buying a coating thickness gauge, confirm one by one: substrate and principle, range and accuracy expression, instrument type, calibration-certificate form and traceability body,…