PosiTest Pull-Off Adhesion
Measures adhesion of coatings to metal, wood, concrete and other substrates
The PosiTest Adhesion Tester literature is available online
Overview: Measures adhesion of coatings to metal, wood, concrete and other rigid substrates Revolutionary self alignment features and pull rate indicator. Conforms to national and international standards including ASTM D4541/D7234, ISO 4624/16276-1, AS/NZS 1580.408.5 and others
Two Models (now available in Manual or Automatic)
The PosiTest Pull-Off Adhesion Tester measures the force required to pull a specified
test diameter of coating away from its substrate using hydraulic pressure.
|Rugged Features: With an environmentally sealed, metal enclosure, heavy duty hydraulic pump and a hi-grade industrial pressure sensor, both the Manual and Automatic PosiTest AT are built to last and can be used indoors and outdoors in all types of weather.|
Unequal pulling force during testing caused by uneven adhesive bond lines and coating surfaces can result in random, unexplainable readings. To obtain more repeatable and meaningful adhesion measurements, it is imperative that the pulling force applied to the test dolly is uniformly distributed over the surface being tested.
Both the PosiTest AT manual and AT-A automatic compensate for misalignment. The self-aligning, quick-coupling actuator and spherical articulating dolly head enable uniform distribution of the pulling force over the surface being tested, preventing a one-sided pull-off.
Technical Data (AT manual and AT-A automatic)
Conforms to national and international standards including ASTM D4541/D7234,
ISO 4624/16276-1, AS/NZS 1580.408.5 and others
PosiTest AT (manual model kit shown above)
Resolution: 1 psi (0.01 MPa)
Accuracy: Â± 1% Full Scale
Warranty: 2 Years
Q & A
Are there different models of PosiTest Adhesion Tester to choose from?
Yes, there are two models to choose from. The PosiTest AT-A features an automatic hydraulic pump while the PosiTest AT comes with a manual hydraulic pump.
What are the differences between the current PosiTest AT Manual and the new PosiTest AT-A Automatic?
The New PosiTest AT-A is an automatic version of the popular PosiTest AT Manual Adhesion Tester. The electronically controlled hydraulic pump automatically applies smooth and continuous pull-off pressure at a user-specified rate.
New features include...
Aside from a few functional differences, your customers will find the New PosiTest AT-A Automatic Adhesion Tester comparable to the current PosiTest AT Manual Adhesion Tester in all respects but the pump.
Are they rugged?
Absolutely. With an environmentally sealed, metal enclosure, heavy-duty hydraulic pump and a hi-grade industrial pressure sensor, both the Manual and Automatic PosiTest AT are built to last and can be used indoors and outdoors and in all types of weather.
What are the benefits of the optional PosiSoft software?
All PosiTest Adhesion Testers have memory for storing data on 200 pulls. This includes maximum pull-off pressure, rate of pull, test duration and dolly size. PosiSoft software downloads this information to a PC. A unique âListen-to- Gageâ feature allows for real time graphing of individual pulls for a more detailed analysis of applied pressure over time (Manual model only).
How are the Manual and Automatic PosiTest Adhesion Testers calibrated at DeFelsko?
The Manual and Automatic PosiTest Adhesion Testers are calibrated against known conditions using NIST traceable equipment. A Certificate of Calibration containing actual measurements is included with every tester.
How much time should be allowed for the included Araldite 2011 to cure?
Are curved dollies available for convex surfaces?
We do not provide or support the use of curved dollies for adhesion testing.
In addition to affecting the surface area used in calculating pull off strengths and the direction of the force lines (creating unwanted shear forces), most adhesion testing standards specifically call for the use of flat dollies.
Feedback from our customers is that most internal or external pipe applications greater than 200 mm in diameter do not require curved dollies for satisfactory results. In such cases the maximum adhesive gap between the surface of the dolly and the coating is 0.5 mm.
For smaller pipe diameters, depending on the expected pull off strength of the coating, it may be possible to use a 10 mm or 14 mm dolly. The smaller surface areas of the dollies will allow them to sit flatter on the curved surface. The height of the actuator pulling the dolly becomes the limiting factor within internal diameters. External diameters can be decreased to as low as 50 and 100 mm respectively.
If you have more specific information on the application it may be possible to provide a more definitive response.
Can pull-off adhesion tests be conducted underwater?
The PosiTest can be used for underwater measurement provided only the cable and actuator are placed under the surface. In such cases, the following precautions should be taken.
Note: During measurement, the manual PosiTest AT may require more than one continuous stroke to complete the test. This differs from our recommendation in the instruction manual and operational video.
PosiTest adhesion testers can be specifically manufactured with longer pressure hoses to facilitate underwater measurement.
Where does failure occur?
Tensile adhesion pulls are evaluated in pounds per square inch (psi) or megapascals (MPa), and visually, as follows:
|PosiTest AT - Adhesion Tester|
|ATM20A||PosiTest AT Manual Pull-Off Adhesion Tester 0 - 3000 PSI / 0 - 20 MPa / 20MM DOLLY|
|ATM50A||PosiTest AT Manual Pull-Off Adhesion Tester 0 - 3000 PSI / 0 - 20 MPa / 50 MM DOLLY|
|ATA20A-B||PosiTest AT Automatic Pull-Off Adhesion Tester 0 - 3000 PSI / 0 - 20 MPa / 20MM DOLLY|
|ATA50A-B||PosiTest AT Automatic Pull-Off Adhesion Tester 0 - 3000 PSI / 0 - 20 MPa / 50MM DOLLY|
|AT50KIT||PosiTest AT Includes 50 mm stand-off, holesaw and test dollies (12) 0 - 500 psi / 0 - 3.5 MPa|
|DOLLY20||PosiTest AT Additional 20 mm dollies (10)|
|DOLLY50||PosiTest AT Additional 50 mm dollies (4)|
|ATADHESIVEKIT||PosiTest AT Adhesive Kit (additional adhesive, mixing sticks, palettes, cotton swabs)|
|TMPLTAS||PosiTest AT Drilling Template for 50 mm Dollies|