Faqs

Summary FAQ's

Are there different models of TQC Adhesion Tester to choose from?
What are the differences between the current PosiTest AT Manual and the new PosiTest AT-A Automatic?
Are they rugged?
How are the Manual and Automatic PosiTest Adhesion Testers calibrated ?
Can pull-off adhesion tests be conducted underwater?
Where does failure occur?
What are the benefits of the optional PosiSoft software?
How much time should be allowed for the included Loctite 907 to cure?
Are curved dollies available for convex surfaces?

Are there different models of TQC Adhesion Tester to choose from?

Yes, there are two models to choose from. The TQC 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.

Extra features include...
Test with the simple push of a button. No twisting, pumping or cranking. No valves to close, needles to reset, or scales to adjust User-selectable pull rates ensure compliance with international test methods for a variety of industries including metal, wood and concrete Built-in rechargeable batteries perform over 200 tests per charge. Continue testing with AC power while batteries recharge. Supplied with universal AC Adapter

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.

How are the Manual and Automatic PosiTest Adhesion Testers calibrated ?

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.

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.

The standoff and actuator should be thoroughly dried immediately upon completion of testing.
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. 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:
*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, and may require re-gluing.

What 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).

How 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.

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 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.

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