Faqs
Übersicht FAQs
Are there different models of the PosiTest Adhesion Tester?
What are the differences between the current PosiTest AT-M Manual and the PosiTest AT-A Automatic?
Are the PosiTest Adhesion Testers rugged?
What are the benefits of the optional PosiSoft software?
How are the Manual and Automatic PosiTest Adhesion Testers calibrated at DeFelsko?
How much time should be allowed for the included Loctite 907 to cure?
Are curved dollies available for convex surfaces?
Can pull-off adhesion tests be conducted underwater?
Where does failure occur?
Are there different models of the PosiTest Adhesion Tester?
Yes, there are two models to choose from. The PosiTest AT-A features an automatic hydraulic pump, the PosiTest AT a manual hydraulic pump.
AufwärtsWhat are the differences between the current PosiTest AT-M Manual and the PosiTest AT-A Automatic?
The PosiTest AT-A is an automatic version of the popular PosiTest AT-M Manual Adhesion Tester. The hydraulic pump is electronically controlled and automatically applies smooth and continuous pull-off pressure at a user-specified rate.
New features include...
- Test with a sole push of a button. No twisting, cranking or pumping. No valves to close, no needles to reset, no scales to adjust
- User-selectable pull rates ensure compliance with international test standards for many industries including metal, wood and concrete
- Built-in rechargeable batteries perform over 200 tests per charge. While batteries recharge , use AC Power to continue testing. A universal AC Adapter is part of the standard supply.
Apart from few functional differences, the PosiTest AT-A Automatic Adhesion Tester can be compared to the PosiTest AT-M Manual Adhesion Tester in all respects but the pump.
AufwärtsAre the PosiTest Adhesion Testers 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 for both indoor and outdoor purposes in any kind of weather.
AufwärtsWhat are the benefits of the optional PosiSoft software?
All PosiTest Adhesion Testers can store data of 200 pulls in the internal memory. This includes maximum pull-off pressure, rate of pull, test duration and dolly size. PosiSoft software downloads this information to a PC. A unique “Listen-to- Gage” feature allows for real time graphing of individual pulls for a more detailed analysis of applied pressure over time (Manual model only).
AufwärtsHow 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. Each PosiTest Adhesion Tester comes with a certificate of Calibration containing actual measurements.
AufwärtsHow much time should be allowed for the included Loctite 907 to cure?
Complete cure is obtained after 24 hours at room temperature. HYSOL 907 will achieve handling strength in 3-4 hours at 25°C (note: this can vary with different bond configurations). Hysol 907 can also be fully cured with heat such as 2 hours at a 60°C or 1 hour at 85°C. See Product Description Sheet for full details.
AufwärtsAre 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 specify the use of flat dollies.
Field experience learns that most internal or external pipe applications with a diameter greater than 200 mm do not require curved dollies for satisfactory results. In these cases the maximum adhesive gap between the coating and the surface of the dolly is 0.5 mm.
For smaller pipe diameters, depending on the expected pull-off strength of the coating, a 10 mm or 14 mm dolly may be used. The smaller surface areas of the dollies allows them to rest flatter on the curved surface. The height of the actuator pulling the dolly is the limiting factor within internal diameters. External diameters can be decreased respectively to as low as 50 and 100 mm.
With more specific information on the application it may be possible to provide a more definitive response.
AufwärtsCan pull-off adhesion tests be conducted underwater?
With the PosiTest Adhesion Tester underwater measurement can be performed provided only the cable and actuator are placed under the surface. In these cases, this precautions need to be taken:
- The standoff and actuator should be thoroughly dried immediately after the test is completed.
- Once dried, a generous amount of lubricant should be applied to discourage corrosion (rust).
Note: During measurement, the manual PosiTest AT may require more than one continuous stroke to complete the test. The instruction manual and operational video state something different.
PosiTest adhesion testers can be specifically manufactured with longer pressure hoses to facilitate underwater measurement.
AufwärtsWhere does failure occur?
Tensile adhesion pulls are evaluated in pounds per square inch (psi) or megapascals (MPa), and visually, as follows:
- Adhesion failure - defined as a failure between two distinct paint layers or between the substrate and the first layer of paint.
- Cohesion failure - defined as a failure or break within one coat of paint (the coating breaks within itself).
- Glue failure - coating bond exceeds the glue strength. Re-gluing may be required.
Zurück
