DeFelsko PosiTest AT User Manual [en, de, es, fr]

®

PosiTest

Pull-Off Adhesion Tester

INSTRUCTION MANUAL v. 4.0

PosiTest AT-M

(manual)

PosiTest AT-A

(automatic)

Introduction

Introduction

The portable, hand-operated PosiTest Pull-Off Adhesion Tester measures the
force required to pull a specified test diameter of coating away from its substrate
using hydraulic pressure. The pressure is displayed on a digital LCD and repre­sents the coating's strength of adhesion to the substrate.

In accordance with ASTM D4541, D7234, ISO 4624 and others, the PosiTest
evaluates the adhesion (pull-off strength) of a coating by determining the greatest
tensile pull-off force that it can bear before detaching. Breaking points,
demonstrated by fractured surfaces, occur along the weakest plane within the
system consisting of the dolly, adhesive, coating layers and substrate.

NOTE:

about the particular topic or feature is available on our website.

Throughout this manual, the symbol indicates more information

Go to: www.defelsko.com/manuals

Basic steps for testing coating adhesion with a PosiTest Adhesion Tester:

1. Dolly & Coating Preparation

The dolly and the coating are cleaned and abraded. (see pg. 4)

2. Adhesive & Dolly Application

The adhesive is prepared and applied to the dolly . The dolly is then adhered
to the coated surface and the adhesive is allowed to cure. (see pg.4)

3. Test Area Separation - Optional step

The test area of the coating is separated from the area surrounding the
dolly by cutting or drilling. (see pg. 5)

4. Pull-off Test

a) PosiTest AT-M (manual) (see pg. 6)
b) PosiTest AT-A (automatic) (see pg. 8)

5. Analysis of Test Results

The dolly and the coating are examined and evaluated to determine the
nature of the coating failure. (see pg. 10)

6. Store Pull-Off Test Results - Optional step

The PosiTest’s internal memory stores maximum pull pressure, pull rate,
test duration and dolly size for up to 200 pulls. (see pg. 10)

Page 3

Step 1: Dolly & Coating Preparation

Step 1: Dolly & Coating Preparation

Dolly Preparation

1. To remove oxidation and contaminants, place the included abrasive pad on a

flat surface and rub the base of the dolly across the pad 4-5 times.

2. As required, remove residue left from the abrading process using a dry cloth
or paper towel.

Coating Preparation

1. Lightly roughen the coating using the included abrasive pad.

NOTE:

necessary to remove surface contaminants, or when the bond strength between
the adhesive and the coating is insufficient for pull testing.

2. To promote the bond between the dolly and the coating, degrease the area of
the coating to be tested using alcohol or acetone to remove any oil, moisture
or dust.

NOTE:

sives do not alter the properties of the coating. Test by applying a small amount
of degreaser or adhesive to a sample area and observing effects.

Step 2: Adhesive & Dolly Application

Step 2: Adhesive & Dolly Application

As coating abrasion may introduce flaws, it should only be used when

Ensure that any alternative abrasion techniques, degreasers or adhe-

Adhesive Selection

The adhesive included in the PosiTest Adhesion Tester kit has been selected due
to its versatility. This adhesive has minimal impact on a variety of coatings and
has a tensile strength exceeding the maximum performance capabilities of the
pressure system under ideal conditions. Other adhesives may be preferred based
on requirements such as cure time, coating type, working temperature and pull­off strength. Quick curing one-part cyanoacrylates (super glues) may be sufficient
for painted surfaces, but two-part epoxies are preferred for porous or rough coat-

ings

Dolly Application

1. Mix the adhesive per manufacturer’s instructions and apply a uniform film of

adhesive on the base of the dolly (approximately 2-4 mils or 50-100 microns
for best results)

2. Attach the dolly to the prepared coating test area.

NOTE:

hold the dolly in place during the cure time may be required, i.e. removable tape.

If the coated surface to be tested is overhead or vertical, a means to

Page 4

3. Gently push down on the dolly to squeeze out excess adhesive. Do not twist

or slide the dolly back and forth on the coating as air bubbles may be gener­ated.

4. Carefully remove excess adhesive from around the edges of the dolly with

included cotton swabs.

5. Allow to cure per the adhesive manufacturer's instructions

NOTE:

with heat. Similarly, cold environments may cause a longer cure time and weak­er bond strength.

Step 3: Test Area Separation

Step 3: Test Area Separation

The decision of when to cut around a dolly is dependent on the standard,
specification or contractual agreement to which the test is to comply. The primary
purpose for cutting through the coating is to isolate a specific diameter test area.
When the decision to cut into the coating has been made, it is recommended to
cut all the way through to the substrate. As a minimum, it is suggested to carefully
cut away excess adhesive from the dolly application process. This typically
prevents a larger area of coating from being pulled away from the substrate,
resulting in a higher pull-off pressure.

Many adhesives cure faster and provide a stronger bond when cured

Cutting Instructions

1. Cut through the coating around the edges of the dolly with the included cut-

ting tool, removing any excess adhesive.

2. Clear away any debris from the cutting process.

NOTE:

- Cutting may induce coating surface flaws such as microcracking that

may alter test results.

- For coatings with strong lateral bonding it is recommended to cut

completely through the coating down to the substrate.

Drilling Template

When testing very thick coatings, an optional drilling template may be preferred.

Page 5

Step 4a: Pull-Off Test

Step 4a: Pull-Off Test

(PosiTest AT-M Manual)

Pump Handle

Actuator Handle

Hose

Actuator

Assembly

Quick Coupling

The PosiTest AT-M powers-up and displays dashes when the button is
pressed. To preserve battery life, the instrument powers down after 5 minutes of

no activity.

LCD

Pump

USB Data Transfer /
Power Port

Quick Guide

(1) Open the pressure relief valve completely (turn counter clockwise)
(2) Connect the actuator to the dolly
(3) Close the pressure relief valve completely (turn clockwise)
(4) Zero - Press the Zero button.
(5) Pump pressure into the system until the dolly pulls the coating away

1. Ensure the pressure relief valve on the pump is completely open. (turn

counter clockwise)

OPEN

CLOSE

2. Push the actuator handle completely down into the actuator assembly. Place

the actuator assembly over the dolly head and attach the quick coupling to the
dolly by reaching through the holes in the actuator assembly and lifting the quick
coupling. Release the quick coupling when the dolly head is completely engaged.

Page 6

3. Close the pressure relief valve on the pump completely. (turn clockwise)

NOTE:

button. Select the pressure units by pressing the button. The
instrument will maintain these adjustments even after the button is

pressed.

As required, verify and adjust the dolly size by pressing the

4. Zero the instrument BEFORE pumping by pressing the button. This

prepares the instrument for the test by clearing the display, and zeroing the
instrument.

5. Prime the pump slowly until the displayed reading approaches the priming

pressure. The priming pressure is the point that the instrument begins calculating
and displaying the pull rate. It is also the pressure at which the ability to store

readings is enabled. Priming pressures for the various dolly diameters are:

10 mm 400 psi 2.8 MPa
14 mm 200 psi 1.4 MPa

20 mm 100 psi 0.7 MPa

50 mm 50 psi 0.4 MPa

NOTE:

pump handle to its full upright position and then complete a single stroke at the
desired pull rate until the actuator separates the dolly from the coating.

For optimum results, prior to exceeding the priming pressure, return the

6. Open the pressure relief valve and remove the dolly from the actuator

assembly.

7. Readings may be stored into memory by pressing the button (pg. 10).

Troubleshooting (PosiTest AT-M)

Digital display “freezes” at a low value

The Tester uses a sudden drop in actuator pressure as an indication that the dolly
has been pulled from the surface. The test stops and the highest pressure
remains on the display for easy viewing and recording. Pumping up pressure too
quickly at the beginning of a test can cause a sudden pressure pulse, fooling the
Tester into thinking the test is complete. If this happens, restart the test by
opening the pressure relief valve, closing it, then pressing the button. For
more information, see Step 5 above.

Page 7

Step 4b: Pull-Off Test

Step 4b: Pull-Off Test

(PosiTest AT-A Automatic)

Hose

Actuator
Handle

Actuator

Assembly

USB port

AC Adapter Port
(Charges batteries

and powers instrument)

LCD

Quick
Coupling

Quick Guide

(1) Connect the actuator to the dolly
(2) Power-up with the button
(3) Verify measurement units, dolly size and pull rate
(4) Ready the instrument with the button
(5) Test with the button

1. Place the actuator assembly over the dolly head and attach the quick coupling

to the dolly by reaching through the holes in the actuator assembly and lifting the
quick coupling. Release the quick coupling when the dolly head is completely

engaged.

2. Press the button to power-up the instrument if necessary. The instru-

ment will power-down after 5 minutes of no activity or by holding the but­ton for 2 seconds.

3. Check settings:

(a) Verify displayed measurement units. Change with the button if

necessary.

(b) Verify dolly size with the button and change if necessary.
(c) Verify pull rate with the button and change if necessary. The

following user selectable rates are available:

Dolly Size PSI Rates MPa Rates

10 mm 125, 200, 400, 600, 725 1.00, 2.00, 3.00, 4.00, 5.00
14 mm 60, 100, 200, 300, 360 0.40, 0.70, 1.40, 2.00, 2.50

20 mm 30, 50, 100, 150, 180 0.20, 0.30, 0.70, 1.00, 1.20
50 mm 5, 8, 16, 24, 30 0.04, 0.08, 0.12, 0.16, 0.20

Page 8

4. Press the button to ready the instrument. This prepares the PosiTest

for the test by clearing the display and zeroing the instrument.

5. Press the button again to start the test that consists of 4 stages

that occur automatically:

Stage 1. Initiation - the display shows a blinking "0".

Stage 2. Priming - the pump applies initial pressure to the dolly.

Stage 3. Test - when the priming pressure has been achieved (see step 5 on pg.

7) the instrument begins calculating and displaying the pull rate established by the

user. Pressure build-up stops when the dolly is pulled from the surface or when
the button is pressed.

Stage 4. Retraction - the maximum pull-off pressure value blinks on the display

while the pump retracts the actuator. The buttons are locked during this stage.

CAUTION: To avoid injury, keep fingers away from the quick coupling

and actuator assembly until the pull test has completed and the actuator
has been fully retracted. Press to stop the pull test at any time.

6. Remove the dolly from the actuator assembly.

7. Readings may be stored into memory by pressing the button (pg. 10).

All settings and test results in memory are retained during power-down.
The red button may be pressed to stop the pull test at any time. The

maximum pressure value will remain on the display while the pump retracts the
actuator. This value can be stored into memory and will be uniquely identified by
the optional PosiSoft software. Stopping the pull test before destruction is handy
when specifications allow the test to be stopped when required adhesion
strengths have been exceeded. Uncouple the actuator from the dolly and then
remove the dolly from the surface with a sharp, sideways hammer tap.

Troubleshooting (PosiTest AT-A)

Instrument is unresponsive or will not power down

In the unlikely event that the PosiTest becomes unresponsive or will not
power down, press and hold the button, then press the
button. The instrument will power down.

Page 9

Step 5: Analysis of Test Results

Step 5: Analysis of Test Results

Test results can be considered 100% valid when the coating is completely
removed from the substrate. When only a portion of the coating is removed, spe­cific results should be noted including the fracture pattern to determine the cohe­sive properties of the coating and adhesion properties between the dolly and
adhesive, adhesive and coating, distinct coating layers, and coating and sub­strate.

Step 6: Storing Pull-Off values into Memory

Step 6: Storing Pull-Off values into Memory

The PosiTest’s internal memory stores maximum pull pressure, pull rate,
test duration and dolly size for up to 200 pulls.

Press the button upon completion of a test to store pull-off test
results. The display will show the pull rate and alternate between the test
number and the maximum pull pressure for that test. The con will
appear to indicate that there are test results in memory.

Press the button repeatedly to view previously stored test results.
The PosiTest AT-A also displays dolly size and pull rate by
pressing their respective buttons.

Complete information on all test results can be downloaded to a PC and
viewed using the optional PosiSoft software. Test results are not erased
from memory after downloading. Press (AT-M manual) or
(AT-A automatic) to exit viewing mode.

To remove all stored test results from memory, press and hold the
or button, then press the button. The icon will
disappear from the display.

All settings and test results in memory are retained during power-down.

Available Options

Available Options

A variety of accessories are available to help you get the most out of your
PosiTest Pull-Off Adhesion Tester.

Page 10

Power Supply / Low Battery Indicator

Power Supply / Low Battery Indicator

PosiTest AT-M (manual)

Power Source: Built-in rechargeable NiMH battery (~60 hours continuous)
The built-in rechargeable NiMH batteries** are charged using the included USB

AC power supply/charger. Ensure batteries are charged prior to use. The
symbol will blink while the instrument is recharging and disappear when fully
charged. The charging process will take up to 14 hours depending on remaining
battery power.

Alternatively, the AC power supply or any computer USB port can be used to
power and charge the instrument.

PosiTest AT-A (automatic)

Power Source: Built-in rechargeable NiMH battery (>200 pulls with full charge)
The symbol will appear when remaining battery power is below 35%.
The built-in rechargeable NiMH batteries** are charged using the included AC

power supply/charger . Ensure batteries are charged prior to use. The symbol
will blink while the instrument is recharging and disappear when fully charged.
The charging process will take 2-3 hours depending on remaining battery power .

Alternatively, the AC power supply can be used to power the instrument.

NOTE:

connection will drain battery power when connected for an extended period of
time.

**Do not attempt to remove or replace the internal NiMH battery pack. In the
unlikely event power issues are experienced, please contact our technical
support for assistance.

The USB port will not charge or power the PosiTest AT-A. The USB

Technical Data

Technical Data

Conforms to: ASTM D 4541, ASTM D 7234, ISO 4624 and others.

Specifications:

Resolution: 1 psi (0.01 MPa) Accuracy: ±1% Full Scale

Dolly Size (mm) Max Pull-Off Pressure

10 mm

10,000 psi (70 MPa)

Adhesion
Strength

14 mm
20 mm

6,000 psi (40 MPa)
3,000 psi (20 MPa)

50 mm*

*requires optional 50 mm accessory kit

Page 11

500 psi (3.5 MPa)

Calibration

Calibration

The PosiTest is shipped with a Certificate of Calibration showing traceability to a
national standard. For organizations with re-certification requirements, the
PosiTest may be returned at regular intervals for calibration. DeFelsko
recommends that our customers establish the instrument calibration intervals
based upon their own experience and work environment. Based on our product
knowledge, data and customer feedback, a one year calibration interval from
either the date of calibration, date of purchase, or date of receipt is a typical
starting point.

Returning for Service

Returning for Service

There are no user serviceable components. Any service must be performed by
DeFelsko Corporation.

If you need to return the Instrument for service, describe the problem fully and
include reading results, if any. Be sure to include contact information including
your company name, company contact, telephone number and fax number or

email address.

www.defelsko.com/support

Limited Warranty, Sole Remedy and Limited Liability

Limited Warranty, Sole Remedy and Limited Liability

DeFelsko’s sole warranty, remedy, and liability are the express limited warranty,
remedy, and limited liability that are set forth on its website:

www.defelsko.com/terms

www.defelsko.com

© DeFelsko Corporation USA 2011. All Rights Reserved

This manual is copyrighted with all rights reserved and may not be reproduced or transmit­ted, in whole or part, by any means, without written permission from DeFelsko Corporation.

DeFelsko, PosiTector, PosiTest and PosiSoft are trademarks of DeFelsko Corporation reg­istered in the U.S. and in other countries. Other brand or product names are trademarks or
registered trademarks of their respective holders.

Protection provided by the equipment may be impaired if the equipment is used in a manner
not specified by the manufacturer.

Every effort has been made to ensure that the information in this manual is accurate.
DeFelsko is not responsible for printing or clerical errors.

Medidor de adherencia

por tracción de PosiTest

MANUAL DE INSTRUCCIONES v. 4.0

PosiTest AT-M

(manual)

PosiTest AT-A

(Automático)

Simple. Duradero. Preciso.

Introducción

Introducción

El medidor de adherencia manual portátil por tracción Positest mide la fuerza
necesaria para realizar una tracción de prueba sobre un diámetro específico para
separar un revestimiento de su sustrato con presión hidráulica. La presión se
muestra en una pantalla LCD digital y representa la fuerza de adhesión del reves­timiento a su sustrato.

De acuerdo con las normas ASTM D4541, D7234, ISO 4624 y otras, el PosiTest
evalúa la adhesión (fuerza de tracción) de un revestimiento determinando la
mayor fuerza de tensión por tracción que puede soportar antes de separarse.
Los puntos de fractura que se muestran en las superficies se suceden a lo
largo del plano más débil del sistema formado por la dolly, las capas de reves­timiento y el sustrato.

NOTA:

El símbolo que encontrará en diferentes secciones de este
manual indica que puede encontrar mayor información sobre ese tema o
esa característica en nuestra página web.

Visite: www.defelsko.com/manuals

Pasos básicos para probar la adherencia del revestimiento con un medidor de
adherencia de PosiTest:

1. Preparación del dolly y del recubrimiento

La dolly y el revestimiento estarán limpios y lijados. (consulte la pág. 4)

2. Aplicación del adhesivo y del dolly

Prepare el adhesivo y aplíquelo al dolly. Pegue el dolly a superficie preprada y
deje que el pegamento fragüe. (consulte la pág. 4)

3. Prueba de desprendimiento de la zona - paso opcional

Separe el revestimiento del área de prueba del resto del recubrimiento cor­tando alrededor del dolly. (consulte la pág. 5)

4. Prueba de tración

a) PosiTest AT-M (manual) (consulte la pág. 6)
b) PosiTest AT-A (automático) (consulte la pág. 8)

5. Análisis de los resultados

Examine el dolly , el revestimiento y evalúelos para determinar el fallo. (consulte
la pág. 10)

6. Almacenamiento de los datos de la prueba de tración - paso opcional

La memoria interna de PosiTest almacena la presión máxima de la prueba de
tración, la duración de la prueba y el calibre del dolly hasta 200 traciónes. (con­sulte la pág. 10)

Página 3

Paso 1: Preparación del dolly y el revestimiento

Paso 1: Preparación del dolly y el revestimiento

Preparación del dolly

1. Para eliminar óxido y contaminantes coloque la lija provista sobre una

superficie plana y frote con ella la base de la dolly unas 4 o 5 veces.

2. Si fuera necesario, elimine los residuos resultantes del proceso de lijado con

una bayeta o papel secos.

Preparación del revestimiento

1. Cree una ligera rugosidad en el revestimiento con la lija facilitada.

NOTA:

cuando sea necesario para eliminar residuos de la superficie o cuando la fuerza
de adhesión entre el adhesivo y el revestimiento sea insuficiente para la prueba
de tracción.

2. Para facilitar la adhesión entre el dolly y el revestimiento, desengrase la zona

del revestimiento que se va a probar con alcohol o acetona y retirar así
cualquier grasa, humedad o polvo.

NOTA:

pegado no alteran las propiedades del revestimiento. Haga una prueba apli­cando una pequeña cantidad de desengrasante o adhesivo sobre una zona
de muestra y observe los efectos.

Paso 2: Aplicación del adhesivo y el dolly

Paso 2: Aplicación del adhesivo y el dolly

Selección del adhesivo

El adhesivo facilitado con el medidor de adhesión PosiTest se ha seleccionado
por su flexibilidad. Este adhesivo tiene un impacto mínimo en numerosos reves­timientos y tiene una fuerza de tensión que supera las capacidades máximas
de rendimiento del sistema de presión en condiciones ideales. Otros adhesivos
pueden ser mejores según las necesidades como el tiempo de fragua, tipo de
revestimiento, temperatura de trabajo y fuerza de tensión. Los cianoacrilatos de
fragua rápida de un componente pueden ser apropiados para superficies pin­tadas mientras que las resinas de dos componentes son más adecuadas para
revestimientos porosos o ásperos.

Como el lijado del revestimiento puede crear defectos, utilícelo solo

Asegúrese de que las técnicas alternativas de lijado, desengrasado o

Aplicación del dolly

1. Mezcle el adhesivo según las instrucciones del fabricante y aplique una

película uniforme de adhesivo en la base del dolly (aproximadamente 50­100 micras para obtener mejores resultados)

2. Pegue el dolly al área preparada para la prueba del revestimiento.

NOTA:

vertical o está bajo el techo, puede ser necesario algún sistema de fijación para
el dolly durante el tiempo de fragua, por ejemplo, una cinta adhesiva.

Si la superficie de contacto del revestimiento que se va a probar es

Página 4