How to Measure Surface Profile using the Elcometer 224 ...

The Elcometer 224 is a needle depth gauge, which is very easy to use. Simply zero the gauge on glass, and, when the gauge is placed on the surface, a spring mounted needle measures the depth of the profile from the peaks of the profile at that particular point. As the measurement point is not necessarily at the very bottom of the valley, and could be somewhere on the slope so to speak, the user takes either 5 or 10 individual measurements, after which the gauge then provides a reading. The reading displayed is user selectable, and can either be the more common average peak-to-valley height, or the maximum height.

With the ability to measure profiles up to 500 microns (20 mils), on flat or curved surfaces, the Elcometer 224 Digital Surface Profile GaugeDigital Surface Profile Gauge provides repeatable and reproducible measurements [accurate to ±5%]; can store each reading into memory [150,000 readings in 2,500 batches] – and can instantly transfer them to your PC or mobile device using ElcoMaster; our free, easy-to-use software application, generating professional inspection reports, instantly.

What’s more, the new Elcometer 224’s measurement modes, make sure that you can collect and record the data you need in accordance with your relevant test method, or standard.

As I’ve already mentioned, taking just one reading on a blasted surface will not be representative of the entire surface profile, as the needle could rest in a valley or on any part of the slope. That is why you need to take a number of readings over a small area to get a statistically valid measurement. That’s why most test methods or standards recommend you take multiple readings in one location; some say ten [ASTM 4417-B], others say five [SANS 5772]; and again depending on the standard you should record either the maximum or average of these readings.

The new Elcometer 224 Digital Surface Profile Gauge can store either the average or maximum peak to valley height reading into memory. Alternatively, if you want to store every value, simply select the gauge’s Immediate mode.

So, no matter what number of readings you are required to take, and whether you are required to record the average of the averages, or the average of the maximums; the new Elcometer 224 makes it easy to record the results.

The gauge can also calculate and display statistics live, as you take readings; including the average, low and high values, standard deviation, and coefficient of variation to name a few.

Once you have taken the readings, you now need to decide what to do with them. One way is to write them down individually as you take them, and type them into a spreadsheet later.

Alternatively, connect the Elcometer 224 to your mobile device via Bluetooth, and either transfer the readings from memory, or transfer each reading into the ElcoMaster App, live as you take them. Either way, once the inspection is complete, you can instantly generate and send the inspection report, anywhere in the world, via email or the cloud.

So, when you are measuring surface profile, let the Elcometer 224 and ElcoMaster App, take all the effort.

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Why is Surface Profile Measurement Important?

Steel is often abrasive-blast cleaned or otherwise roughened prior to painting. The peak-to-valley height of the resultant "surface profile" is a critical and determining factor in the performance of applied paint and other protective coatings. A surface profile height that is too low may reduce coating bond strength (adhesion). Too high and the peaks may receive insufficient coverage leading to premature rusting, and often require additional paint (and labor costs to apply it) to cover the anchor profile.

Emerging research over the past 15 years has shown surface profile height is not the only important parameter. Peak density (also known as peak count), the number of peaks in the surface profile per unit area, has been shown to be a strong determinant of coating adhesion and resistance to corrosion. In fact, studies have found that peak density may be a better predictor of coating performance than peak-to-valley height.  

Surface profile height can also be relevant for other industries, as a way to quantify the profile height of non-skid surfaces, and to evaluate the Concrete Surface Profile (CSP) prior to applying coatings on concrete.

See below for more information about surface profile measurement and gauge solutions.