Measuring Profile on Blasted Steel – What is the most accurate Method?

Paint and Blast operators have historically used the Testex Tape system for measuring and recording surface profile following Abrasive Blasting – as it was the simplest way to obtain objective profile readings.  But how reliable and accurate is the Testex Tape system – and are there other profile reading equipment that improves on this system?

Enter the Electronic Profile Reading Devices now available and gaining popularity.  Let’s look at both systems.

When comparing Testex Tape and electronic profile devices to measure surface profiles, several factors impact their accuracy and preference, including precision, ease of use, and industry standards. Below is a detailed comparison:

1. Accuracy

Verdict:

• Electronic gauges tend to be more accurate due to direct measurement and reduced user dependency.
• Testex Tape may introduce variability due to operator technique, tape compression, required dual Tape usage in the 1.5 to 2.5 mil profile and micrometer errors.

2. Preference (Usability & Practicality)

Verdict:

• Testex Tape has historically been preferred for field use due to low cost, simplicity, and no need for power.  However, Dual Tape requirement increases complexity and time.
• Electronic measurement is preferred for high-accuracy applications, quality control, and data logging – and is gaining in overall popularity.

3. Industry Application Considerations

• Coating & Corrosion Inspection: Electronic measurement is often preferred for QA/QC and automated reporting, while Testex Tape has historically been accepted for on-site field measurements.
• Abrasive Blasting & Surface Preparation: Both methods are used, but Testex Tape is commonly referenced in surface profile specifications.
• Regulatory & Compliance: Both are recognized by ASTM and ISO standards, but electronic gauges offer better traceability for audits and reduced time needed for inspection. 

Recommendations for Surface Profile Measurement

1. Electronic Profile Gauges (High Accuracy & Digital Logging)

If you need high accuracy, repeatability, and digital storage, consider the following electronic gauges:

✅ Best for: QC inspections, compliance reporting, digital record-keeping, high-precision surface profiling.
❌ Limitations: Higher cost, requires calibration, and may not be ideal for extreme field conditions.

2. Testex Tape (Portable, Affordable, and Field-Ready)

If you need a low-cost, simple, and field-ready solution, Testex Tape is a great choice. The correct grade depends on the roughness range:

✅ Best for: On-site inspections, field work, quick verification, and low-budget applications.
❌ Limitations: Less precision, requires operator skill, and manual data entry.

Which Should You Choose?

• For high-accuracy quality control & regulatory reporting: Electronic Gauges (e.g., Elcometer 224, Defelsko SPG)
• For field inspections & budget-friendly use: Testex Tape (Coarse, X-Coarse, X-Coarse Plus)
• For best results: Use both—Testex Tape for field verification and electronic gauges for detailed QC and compliance.

Final Conclusion

• If accuracy is the priority → Electronic Profile Measurements is preferred
• If portability and affordability are the priority → Testex Tape
• For regulatory compliance → Both methods are acceptable, but electronic measurements offer better repeatability and digital logging.