How to Measure Adhesion 8:50
Measuring Coating Adhesion to Metals, Concrete, and more with the PosiTest AT from DeFelsko- the Measure of Quality.
The PosiTest AT-A automatic adhesion tester is a fully automatic hydraulic pull-off adhesion tester designed for precision, repeatability, and ease of use. Built to withstand the toughest job sites, it provides highly reliable measurements of coating adhesion strength on metals, concrete, wood, and other substrates.
By automating the pull-off process, the Automatic Adhesion Tester eliminates operator variability and ensures consistent results across multiple tests. This makes it ideal for quality assurance programmes, compliance inspections, and any application where accuracy and documentation are critical.
Supplied exclusively in the UK by DFT Instruments, and supported by our DeFelsko Authorised Service Centre (DASC), the PosiTest AT-A comes fully calibrated, certified, and backed by local service, calibration, and technical expertise.
Features
- Select from four Stand-offs – 20 mm, 50 mm, 50×50 mm Tile and 50 mm C1583
- Environmentally sealed enclosure—weatherproof, dustproof and shockproof—meets or exceeds IP65
- Inexpensive, single-use dollies eliminate cleaning for re-use and can be kept as a permanent record
- Self-aligning aluminum dolly enables accurate measurements on smooth or uneven surfaces
- 10, 14, 20 or 50 mm dollies maximize capability and measurement resolution across a wide range of bond strengths
- Calibrated and certified to ± 1% accuracy using a NIST traceable load cell
- Certificate of Calibration showing traceability to NIST included (Long Form)
Why Testing Matters
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Prevent Coating Failures – Poor adhesion can lead to peeling, blistering, and delamination that compromise asset protection.
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Compliance with Standards – Test to ISO, ASTM, EN, and other recognised industry standards.
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Evidence for Quality Control – Documented pull-off results and fracture analysis provide proof for contracts and audits.
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Optimise Application Methods – Identify weaknesses in surface prep, primers, or coatings before they become costly problems.
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Confidence in Performance – Ensure coatings will withstand real-world stresses over the long term.
Why Choose DFT?
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Official UK Distributor – Genuine DeFelsko instruments supplied direct to the UK market.
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DeFelsko Authorised Service Centre (DASC) – Calibration, servicing, and repair performed locally to factory standards.
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Traceable Calibration Included – Every unit supplied with a calibration certificate traceable to UKAS/NIST/PTB.
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Fast UK Support – Local turnaround, expert advice, and one-day calibration service.
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Trusted Experience – Over 25 years supporting UK industries from marine to aerospace.
Helpful PosiTest Adhesion Testing Videos
PosiTest AT Self-Alignment Feature 2:50
A helpful video showing the self-alignment feature. Both the PosiTest AT-M Manual and PosiTest AT-A Automatic models compensate for misalignment.
Features & Benefits
Easy to Use
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Simple controls to select dolly size, measurement units, and data storage at the touch of a button.
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Low-cost, single-use dollies and plates remove the need for cleaning and can be kept as permanent records.
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Kits include everything needed for testing straight out of the box.
Built for the Field
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Weatherproof, dustproof, and shockproof housing meeting or exceeding IP65 standards.
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Supplied in a protective hard-shell case, with an optional upgrade to a heavy-duty Pelican case.
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Two-year warranty included.
Laboratory-Grade Accuracy
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Calibrated to ±1% accuracy using a NIST traceable load cell.
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Each instrument comes with a Certificate of Calibration traceable to recognised standards.
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Self-aligning aluminium dollies ensure accurate measurements on both smooth and uneven surfaces.
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Conforms to international standards including ASTM C1583/D4541/D7234/D7522, ISO 4624/16276-1, EN 12004-2, and more.
Flexible Testing Options
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Four stand-offs available for a wide range of applications.
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Supports dolly sizes from 10 mm to 50 mm, plus 50 × 50 mm tile and 50 mm C1583 options.
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Internal memory stores maximum pull-off pressure, pull rate, test duration, dolly size, and fracture type.
Smart & Connected
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Electronic hydraulic pump applies smooth, consistent pressure automatically.
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Impact- and scratch-resistant touchscreen (with keypad for gloved operation).
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Built-in Li-ion battery delivers 250+ tests per charge; USB-C port enables fast charging while in use.
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Rotating display for easy use in horizontal or vertical positions.
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Stores up to 100,000 results with pressure-time graphs, fracture type, and batch organisation.
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Integrated USB, WiFi, and Bluetooth for seamless connection to PC, Mac, mobile devices, or PosiSoft Cloud.
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PosiSoft Suite enables reporting, data sharing, cloud backup, and synchronisation across devices.
Models
| Specification | ATA20 | ATA50 | ATA50T (EN 12004-2) | ATA50C (ASTM C1583 / EN 1542) |
|---|---|---|---|---|
| Dolly Size & Stand-Off | 20 mm | 50 mm | 50 × 50 mm Plate | 50 mm |
| Typical Applications | Higher bond-strength coatings on metals | Lower bond-strength coatings on wood, concrete, and plastic | Cementitious adhesives for tiles | Concrete surfaces and overlays |
| Range | 0.7 – 24 MPa 100 – 3500 psi 220 – 7550 N |
0.1 – 3.8 MPa 16 – 560 psi 220 – 7550 N |
0.1 – 3.0 MPa 13 – 440 psi 220 – 7550 N |
0.1 – 3.8 MPa 16 – 560 psi 220 – 7550 N |
| Resolution | 0.01 MPa (1 psi) | 0.01 MPa (1 psi) | 0.01 MPa (1 psi) | 0.01 MPa (1 psi) |
| Accuracy | ±1% Full Scale | ±1% Full Scale | ±1% Full Scale | ±1% Full Scale |
| Included Dollies | Ø20 mm aluminium (20 pcs) | Ø50 mm aluminium (8 pcs) | 50 × 50 mm steel plates (4 pcs, with threaded post) | Ø50 mm steel (4 pcs, ≥25 mm thickness) |
| Cutting Tool | 20 mm hole saw | 50 mm hole saw | – | 50 mm diamond-grit hole saw with arbor |
Typical Applications:
Protective coatings on steel structures.
Concrete overlays, flooring systems, and cementitious adhesives.
Industrial coatings in marine, oil & gas, and construction sectors.
High-strength bonding evaluations in aerospace and automotive.
Memory & Reports
- Internal memory stores maximum pull-off pressure, rate of pull, test duration and dolly size for 100,000 pulls in up to 1,000 batches
- Record the results as pass/fail and the nature of fracture – cohesive, adhesive and glue failures
- Wirelessly connect to your smart device using our free PosiTector App (Apple iOS and Android)
- WiFi technology wirelessly communicates with PosiSoft.net, downloads software updates and allows access to stored measurement data using standard web browsers (see WiFi Features for full details)
- PosiSoft USB Drive – stored readings and graphs can be accessed via USB using universal PC/Mac web browsers or file explorers. No software required
- Compatible with PosiSoft Desktop, PosiSoft.net and PosiTector App (Apple iOS and Android) software solutions
Touch Screen Display
Use the touch screen to interact with menu options. Swipe horizontally to navigate between views or vertically to move between batch readings. Alternatively, the keypad can be used for navigation and selection.
APP Features
- Add images and notes using the camera or keyboard
- Create customized, professional PDF reports
- Share, backup, synchronize and report measurement data
- Auto-pairing Bluetooth (BLE) connection
- See the Help File to learn about how it works
Recording the Nature of the Fracture
Upon completion of a pull-off test, the dolly and coated surface should be examined. In addition to pull-off force, many National and International standards such as ASTM D4541 and ISO 4624 require the nature of the fracture to be recorded.
- Cohesive fracture: fracture occurs within a coating layer (same coating on dolly face and coated surface).
- Adhesive fracture: fracture occurs at the interface between layers (coating on dolly face differs from surface).
- Glue failure: visible separation of the glue from itself, the coating or dolly (no coating visible on the dolly face).
FAQ’s
Is the PosiTest AT suitable for site use?
Yes. Both the Manual and Automatic PosiTest AT are engineered for demanding field conditions. With a sealed metal housing, robust hydraulic pump, and industrial-grade pressure sensor, they’re built to withstand dust, water, and impact (IP65 rated). The Automatic model also includes rubberised grips and a shoulder strap for extra convenience when working on site.
Do the kits include dollies?
All PosiTest AT kits come with self-aligning loading fixtures designed to meet international standards. The 20 mm and 50 mm models use precision aluminium dollies, while the 50 × 50 mm Tile and 50 mm C1583 kits are supplied with steel dollies. Both aluminium and steel dollies are intended for single use, which avoids cleaning, reduces contamination risk, and allows them to be kept as a permanent record of testing.
Which adhesive should I use?
Every PosiTest AT kit includes ResinLab EP11HT epoxy adhesive, which is suitable for most coating systems and substrates. For specialist coatings or unusual applications, alternative adhesives may be required — our team can advise if a different adhesive is more appropriate.
Is the Automatic model more accurate than the Manual?
Both instruments are certified to ±1% accuracy. The key difference is that the Automatic model applies hydraulic pressure electronically, removing potential operator influence and producing more consistent results, especially in formal inspection and quality assurance programmes.
What’s the difference between 20 mm and 50 mm dollies?
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20 mm: Best for high bond-strength coatings on metals or other strong substrates.
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50 mm: Recommended for concrete, wood, and composites where adhesion is typically lower.
The choice of dolly size ensures the test is suited to both the substrate material and expected adhesion range.
Can the PosiTest AT be used on pipes or curved surfaces?
Yes, for larger diameters. Customers report reliable performance on internal or external pipes greater than 200 mm in diameter, with a maximum glue gap of 0.5 mm. For smaller pipes, 10 mm or 14 mm dollies may be used where appropriate. Flat dollies are required for compliance with international standards, so curved dollies are not recommended.
How long does the AT-A battery last?
The Automatic model uses a rechargeable Li-ion battery capable of more than 250 tests per charge. It features a USB-C port for fast charging, and the instrument can also operate while charging — ensuring uninterrupted use.
What is the lowest adhesion strength measurable?
With a 50 mm dolly, the AT-A requires a priming pressure of 16 psi before recording measurements. Below this, results may not be consistent. The Manual model can be used more gradually at very low pressures, but both models maintain the same ±1% accuracy across their full scale.
Is there a faster-curing adhesive option?
The supplied epoxy cures within 24–48 hours, which suits most inspection schedules. For faster turnaround, some users employ cyanoacrylate (superglue) adhesives for lower-strength coatings. Always confirm compatibility with both the coating and the test dolly material.
What is the minimum substrate thickness required?
There is no strict minimum, but adhesion results can be influenced if the substrate bends or deforms under load. ISO 16276 recommends a minimum of 3 mm for steel substrates. For thinner materials, support fixtures or backings should be used to prevent flexing during the test.
Can I test flexible or brittle substrates?
Adhesion testing is designed for rigid materials. Flexible substrates may distort the readings, while brittle substrates may crack or shatter during testing. In these cases, results may reflect substrate failure rather than coating adhesion.
Are PosiTest AT instruments calibrated before shipping?
Yes. Every tester is calibrated at the factory and supplied with a long-form Certificate of Calibration traceable to UKAS/NIST/PTB standards. This certificate documents actual test results, unlike basic “conformance” certificates offered by some competitors.
Do I need training to use a PosiTest AT?
No specialist training is required. The gauges are straightforward to operate and are supported by clear manuals, quick guides, and tutorial videos. If you need help, our UK team offers ongoing telephone and email support.
Still need help?
If you experience an issue, check our troubleshooting guide or contact our support team directly. As a DeFelsko Authorised Service Centre (DASC), DFT Instruments provides calibration, repair, and technical assistance locally in the UK.
Find out more about the PosiTest AT-A and all the features that come with it
What’s Included in Each Kit:
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Automatic Adhesion Tester (AT-A)
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Built-in rechargeable Li-ion battery + charger
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Dollies (quantity varies by model)
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Abrasive pad, cutting tool, adhesive, mixing sticks & palettes, cotton swabs
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USB cable + PosiSoft software
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Instruction manual & quick guide
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Shoulder strap
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Certificate of Calibration (traceable to NIST/UKAS)
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Protective carrying case (upgradeable to Pelican)
The PosiTest AT-A combines automation, accuracy, and durability to deliver world-class adhesion testing—now available with full UK support and calibration through DFT Instruments.
📞 To enquire about this product, contact our team today on: 01442 879494 or Complete the form.