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User Guide
Elcometer 138
Abrasive Soluble Salt
Test Kit - ASTM D4940

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CONTENTS
Section1
Overview
2
Box Contents
3
Test Procedure: ASTM D4940
4
Spares & Accessories

Page
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Appendix A: The Elcometer 138 Conductivity Meter

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For the avoidance of doubt, please refer to the original English language version.
Kit Dimensions:456 x 384 x 127mm (18 x 15.1 x 5")
Kit Weight:
2.2kg (4lb 14oz)
A Material Safety Data Sheet for the Elcometer 138 Standard 1413μS/cm Calibration Solution is available todownload via our website:
http://www.elcometer.com/images/stories/MSDS/Elcometer_138_1413uScm_Calibration_Solution.pdf
CAUTION
If the standard solution used for calibration of the meter comes into contact with the skin, wash theskin with fresh water. If the standard solution comes into contact with eyes, immediately flush theeye with large amounts of fresh water and seek medical advice.
© Elcometer Limited 2020. All rights reserved. No part of this document may be reproduced, transmitted,
transcribed, stored (in a retrieval system or otherwise) or translated into any language, in any form or by anymeans (electronic, mechanical, magnetic, optical, manual or otherwise) without the prior written permission of
Elcometer Limited.

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1 OVERVIEW
Abrasives used for blast cleaning surfaces can be contaminated withsoluble salts due to the source or the re-use of the blasting media.
This contamination can be transferred to the blast cleaned surface andresult in accelerated corrosion conditions and also cause premature
coating failure, if this contamination is not removed prior to applying
the coating.
Testing abrasives for soluble salt contamination can be carried out
quickly and easily using the Elcometer 138 Abrasive Soluble Salt Test
Kit, according to the ASTM D4940 method.
Elcometer 138 Abrasive Soluble Salt Test Kit provides all theequipment needed to carry out the test in the field or in the laboratory.

2 BOX CONTENTS<

Elcometer 138 Conductivity Metera<

Calibration Solution 1413µS/cm; 14ml (0.47 fl oz)<

Conditioning Solution; 14ml (0.47 fl oz)<

Bottle of Pure Water; 1000ml (33.8 fl oz)<

Glass Beaker; 100ml (3.4 fl oz)<

Glass Beaker; 600ml (20.3 fl oz)<

Plastic Measuring Beaker; 500ml (16.9 lf oz)<

Funnel<Stirring Rod<

Filter Papers; Box of 100<

CR2032 Lithium Batteries; x2 (supplied fitted to the Elcometer 138)<

Transit Case<

User Guidea

The Elcometer 138 Conductivity Meter included in the test kit measures the conductivity of aqueous
solutions. The meter is NOT designed to measure solids, organic solvents, surfactant, oil, adhesive,
alcohol, strong acids (pH: 0 to 2) or strong alkalis (pH: 12 to 14). The life of the sensor will be extremely
short if these substances are measured.

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3 TEST PROCEDURE: ASTM D4940
3.1 BEFORE YOU START
1
Calibrate the conductivity meter, see Appendix A, Section A2.5 on
page en-11.
2
Determine the conductivity meter sensor cell constant, see
Section 3.2 below.
3
Rinse the beakers, stirring rod and funnel with pure water until
tests show the rinse water has a conductivity of 5µS/cm or less.
4 Measure the conductivity of the rinse water using the Elcometer 138

Conductivity Meter, see Appendix A, Section A2.6 on page en-12.

4

As the test is sensitive, we recommend that clean latex or nitrile
gloves are worn during the test procedure to prevent crosscontamination.

3.2 DETERMINING THE SENSOR CELL CONSTANT (K25)
The conductivity meter sensor cell constant should be determined andchecked periodically using the procedure outlined below.
The Elcometer 138 Conductivity Meter and standard 1413 µS/cm(1.413 mS/cm) calibration solutionb supplied in the kit can be used forthis purpose.
1

Using the Elcometer 138 Conductivity Meter, measure theconductivity of the standard calibration solution at 25°C (77°F),
see Appendix A, Section A2.6 on page en-12.
4 Rinse the sensor cell several times with the solution to be measured before

taking the reading.

2

Calculate the sensor cell constant (K25) using the following
formula:K25 = (Cs / Cm)
where:
K25 = conductivity sensor cell constant
Cm = measured conductivity of the standard calibration solution
Cs = specific conductivity of the standard calibration solution(1413 µS/cm if using the standard calibration solution supplied.)

Note: Users can prepare their own potassium chloride solution instead of using thestandard calibration solution supplied. Refer to the ASTM Standard for further
information.
b

Additional bottles of calibration solution are available to purchase from Elcometer or your local Elcometer
supplier, see Section 4 ‘Spares & Accessories’ on page en-5.

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3 TEST PROCEDURE: ASTM D4940 (continued)
3.3 TEST PROCEDURE
1
Measure out 300ml of abrasive in the 600ml glass beaker thenadd 300ml of pure water.
2
Stir the solution for one minute using the stirring rod. Leave tostand for 8 minutes, then stir again for a further one minute.
3
Insert a filter paper into the funnel and filter a sufficient amount of
the solution into the 100ml glass beaker, discarding the first 10mlof filtrate.
4
Rinse the Elcometer 138 Conductivity Meter sensor cell with purewater until tests show the rinse water has a conductivity of 5µS/cm
or less, see Appendix A, Section A2.6 on page en-12.
5
Measure the conductivity of the solution using the Elcometer 138
Conductivity Meter, see Appendix A, Section A2.6 on page en-12.
4 Rinse the sensor cell several times with the solution to be measured before

taking the reading.

6

Measure the conductivity of successive portions of the solution
until a constant value is obtained.

Stir: 1 Min
Stand: 8 Min
Stir: 1 Min

3.4 CALCULATE THE CONDUCTIVITY OF THE ABRASIVE (Cs)
Calculate the specific conductivity of the abrasive (Cs) using thefollowing formula:Cs = Cm x K25
where:
Cs = specific conductivity of the abrasive
Cm = measured conductivity of abrasive / pure water solution
K25 = conductivity cell constant, see Section 3.2 on page en-3.
3.5 AFTER TEST
Rinse all components of the test kit in pure water. They can then be
re-used.
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4 SPARES & ACCESSORIESThe Elcometer 138 Abrasive Soluble Salt Test Kit is complete with all
the items required to get started and take measurements however,
over the life of the kit, replacements may be required. The following
items are available from Elcometer or your local Elcometer supplier.
Description
Elcometer 138 Conductivity Meter
Replacement Sensor for Conductivity Meter
Standard 1413μS/cm Calibration Solution;
250ml (8.45ﬂ oz) Bottle
Bottle of Pure Water; 1000ml (33.8 ﬂ oz)
Glass Beaker; 100ml (3.4 ﬂ oz)
Glass Beaker; 600ml (20.3 ﬂ oz)
Plastic Measuring Beaker; 500ml (16.9 ﬂ oz)
FunnelStirring Rod
Filter Papers; Box of 100

Part Number
E138-CMT13830628
T13830629-2
T13827494
T13827495
T13827496
T13827498
T13827497
T13827499
T13827500

A Material Safety Data Sheet for the Elcometer 138 Standard 1413μS/cm Calibration Solution isavailable to download via our website:
http://www.elcometer.com/images/stories/MSDS/Elcometer_138_1413uScm_Calibration_Solution.pdf
CAUTION
If the standard solution used for calibration of the meter comes into contact with the skin,wash the skin with fresh water. If the standard solution comes into contact with eyes,
immediately flush the eye with large amounts of fresh water and seek medical advice.

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Appendix A
Elcometer 138
Conductivity Meter

SectionA1
The Controls & Display
Using the Elcometer 138
A2
Care & Maintenance
A3
A4
Warranty Statement
Technical Specification
A5
A6
Spares & Accessories
A7
Legal Notices & Regulatory Informationwww.elcometer.com

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A1: THE CONTROLS & DISPLAY
The Elcometer 138 Conductivity Meter is operated using 3 buttons
and displays readings and other information on the LCD screen.
5
2

6

4

7
3

1

8

ELCOMETER 138 CONDUCTIVITY METER OVERVIEW
1

Measurement Cell

Place a liquid sample in this cell to measure it withthe electrode located on the bottom of the cell.

2

Protection CoverProtects the measurement cell and ﬂat sensor instorage.

3

Lithium Batteries

CR2032 x 2

4

MEAS Button

Sets the measurement mode (EC). View theambient temperature measured with the internal
temperature sensor (to be used as a guide only).
Switches from calibration mode to measurement
mode.

5

ON/OFF Button

Turns the meter On / Oﬀ.

6Strap Eyelet

A strap can be attached here.

7

CAL Button

Starts calibration procedure.

8

Waterproof Gasket

Makes the meter waterproof.

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A1: THE CONTROLS & DISPLAY (continued)
10

9

J

11

MEAS CAL

EC

12

13

°C BATT

0000 µS/cm

14
15

DISPLAY INDICATORS
9

Stability Icon

Illuminates when measured value is stabilised.

10 MEAS Icon

Illuminates when in measurement mode.

11

Flashes during calibration and illuminates steadily
when calibration is ﬁnished.

CAL Icon

12 Temperature Alarm
Icon

Flashes when the ambient temperature does notmeet the speciﬁed operating temperature of 5°C to
40°C (41°F to 105°F).

13 Battery Alarm Icon

Illuminates when the batteries are low and need tobe replaced.

14 Measurement Units

The default setting is µS/cm

15 Measured Value

Displays the measured conductivity of the sample

A2 USING THE ELCOMETER 138
A2.1 CAUTIONŸ
The sensor is a consumable part. If it becomes damaged or its
performance deteriorates, it will need to be replaced - see
Section A6 ‘Spares & Accessories’ on page en-14.
Ÿ
Do not drop the meter.
Ÿ
Never apply undue force when opening the meter (to change thebatteries or sensor).
Ÿ
Do not exert undue force on the sensor.
ŸDo not allow utensils (tweezers, pipette, etc) to touch sensor cell.
ŸDo not measure samples hotter than 40°C (105°F).
Ÿ
Do not allow contact with solvents.
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A2: USING THE ELCOMETER 138 (continued)ŸŸŸDo not subject the meter to high temperature or humidity.
Although the product is waterproof, avoid immersing itcompletely. If the meter is accidentally dropped in water, take itout and remove the moisture.
To ensure the meter is waterproof check that the waterproof
gasket is clean, not damaged, Seated properly in the groove andis not twisted or warped.

A2.2 FITTING AND REPLACING THE BATTERIESThe Elcometer 138 Conductivity Meter uses dry cell batteries only andis supplied with two CR2032 lithium batteries fitted with an isolation
strip. Remove the isolation strip before first use.
To fit or replace the batteries:
1
Place batteries in the battery clips ensuring correct polarity.
2
To reassemble the meter, slide the sensor onto the body of themeter and push the body and sensor together gently until sensor
retaining clip engages.

Battery

Battery
Clip

When the battery voltage becomes low, the low battery warning
indicator will flash. Replace both batteries immediately.
Note: Lithium batteries must be disposed of carefully to avoid environmental
contamination. Please consult your local Environmental Authority for information
on disposal in your region. Do not dispose of any batteries in fire.

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A2: USING THE ELCOMETER 138 (continued)
A2.3 ATTACHING & DETACHING THE SENSOR
Ensure the meter is turned OFF before attaching / detaching thesensor. If the meter is turned ON with the sensor detached, thebattery alarm may illuminate. In this case, turn the meter OFF andattach the sensor, and then turn the meter ON again.
Attaching the sensor:
1
Ensure that the waterproof gasket is clean
and undamaged.
2
Slide the sensor across the meter so theclip (A) fits into the hole on the sensor
tongue (a), as shown.

Waterproof
GasketNote: Ensure that the waterproof gasket is lying flat and not twisted.

Detaching the sensor:
1
Lift the sensor tongue tip and slide thesensor slightly away from the meter.
2
The sensor can now be completely
removed from the meter.
When removing the sensor, do not let any
water penetrate the inside of the meter. If
some moisture remains on the waterproof
gasket, very carefully wipe the moisture off.
Correct procedure for closing meter after removal of the sensor:
Ensure that the sensor tongue is outside the meter case. If the tongue
is inserted between the case and the connector of the meter, it may
damage the connector.
Sensor Tongue

Meter

Connector

ü
SensorMeterû
SensorMeter

The sensor is a consumable part. If it becomes damaged or its
performance deteriorates, it will need to be replaced, see Section A6‘Spares & Accessories’ on page en-14.
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A2: USING THE ELCOMETER 138 (continued)
A2.4 ELECTRODE SURFACE TREATMENT PROCEDURE
When using the sensor for the first time or again after several weeks of
disuse, perform the electrode surface treatment procedure as follows:1

Put some drops of the conditioning solution into the measurement
cell.
Leave for approximately 10 minutes.
Clean the measurement cell with running water.
Wash the measurement cell with standard solution.
Perform the calibration procedure, see Section A2.5 below.

2
3
4
5

A2.5 CALIBRATING THE ELCOMETER 138
When using the sensor for the first time or again after several weeks of
disuse, perform the electrode surface treatment procedure, see
Section A2.4 above, before calibrating the meter.
1
2
3

Press the ON/OFF button to switch themeter on.
Press the CAL button until CAL appearson the display.
Open the protection cover and place anappropriate amount of the standard
1413µS/cm solution supplied, see Section
A6 ‘Spares & Accessories on page en-14,
into the measurement cell avoiding theinclusion of bubbles. Washing the sensor
with standard solution beforehand may
provide more accurate calibration.

CAL
ButtonProtection
Cover

4 Bubbles in the solution may cause themeasurement to be inaccurate.

Appropriate

Too Little

CellElectrodeen-11

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A2: USING THE ELCOMETER 138 (continued)
4
Close the protection cover and press the CAL button for over 2
seconds. CAL and J ﬂash and the calibration value is displayed.
After the calibration is completed, CAL and J stop ﬂashing andilluminate steadily.
4 If CAL continues to flash and the ‘Err’ (error message) is displayed, thecalibration has failed. Check that the standard solution conductivity is correct
and perform the calibration procedure again after thoroughly cleaning thesensor. If the calibration failed whilst using the correct standard solution, thesensor may be damaged and should be replaced, see Section A6 ‘Spares &Accessories’ on page en-14.

56Clean the sensor with tap water and remove moisture.
Press the MEAS button for 0.5 seconds to enter themeasurement mode and prepare for measurement.

A2.6 TAKING A READING
1
Press the ON/OFF button to switch the meter on.
2
Open the protection cover.
3
Immerse the sensor into the sample and stir
gently 2 or 3 times.
4
Read the value displayed when J appears. J
illuminates when measured value is stabilised.
Note: If a measurement result is out of the speciﬁed
measurement range, the displayed measured value
ﬂashes.
Note: Although this product is waterproof, avoid immersing it completely. If the productis accidentally dropped into water, take it out of the water and remove themoisture from the instrument.

A2.7 AFTER MEASUREMENT
1
Press the ON/OFF button to switch the meter oﬀ.
2
Wash the sensor with tap water and wipe away any residual
water using a clean tissue.
3
Replace the sensor protection cap.
Note: If the meter is to remain unused for a long period of time, use pure water insteadof tap water to wash the sensor.

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A3: CARE & MAINTENANCE
The Elcometer 138 Conductivity Meter is designed to give many years
reliable service under normal operating conditions.
Ÿ Prolonged periods of non-use may cause the sensor to dry out. Thiscan result in malfunction or unstable readings. Pour conditioning
solution into the sensor cell and leave for a few minutes to allow thesensor to become saturated. Wash the sensor with water prior touse.
Ÿ If the measuring surface of the sensor is contaminated or if air
bubbles are regularly present in the sample, clean the sensor using
a diluted neutral detergent (diluted 100 times).
Ÿ The Elcometer 138 Conductivity Meter incorporates a Liquid Crystal
Display. If the display is heated above 50°C (120°F) it may bedamaged. This can happen if the meter is left in a car parked instrong sunlight.
The Elcometer 138 Conductivity Meter does not contain any userserviceable components. In the unlikely event of a fault, the metershould be returned to your local Elcometer supplier or directly to
Elcometer Limited - contact details can be found on our website,www.elcometer.com. The warranty will be invalidated if the instrument
has been opened.

A4: WARRANTY STATEMENTThe Elcometer 138 Conductivity Meter is supplied with a 12 month
warranty against manufacturing defects, excluding contamination andwear.
The conductivity meter sensor is supplied with a 3 month warranty
against manufacturing defects, excluding contamination and wear.

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A5: TECHNICAL SPECIFICATION
Measurement
Principle

2 Electrode Bipolar AC

Measurement
Mode

Conductivity, Temperature

Minimum Sample
Volume0.12ml

MeasurementRange

0 - 19.99mS/cm

Resolution

0 - 1999µS/cm : 1µS/cm
2.00 - 19.99mS/cm : 0.01mS/cm

Accuracy±2% of full scale (for each range)

OperatingTemperature

5°C to 40°C (41°F to 105°F)

Operating
Humidity

85% or less relative humidity (no condensation)

Battery Type

2 x CR2032 lithium

Battery Life

Approximately 200 hours continuous use
without backlight

Dimensions

164 x 29 x 20mm (6.5 x 1.1 x 0.79")

Weight50g (1.76 oz) - including sensor and batteries

A6: SPARES & ACCESSORIES
Description
Standard 1413μS/cm Calibration Solution:
250ml (8.45ﬂ oz) Bottle
Replacement Sensor for Conductivity Meter

Part Number
T13830629-2
T13830628

A Material Safety Data Sheet for the Elcometer 138 Standard 1413μS/cm Calibration Solution isavailable to download via our website:
http://www.elcometer.com/images/stories/MSDS/Elcometer_138_1413uScm_Calibration_Solution.pdf
CAUTION
If the standard solution used for calibration of the meter comes into contact with the skin,wash the skin with fresh water. If the standard solution comes into contact with eyes,
immediately flush the eye with large amounts of fresh water and seek medical advice.

www.elcometer.com

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A7: LEGAL NOTICES & REGULATORY INFORMATION
Declaration of Conformity: This product complies with the requirements of the following EU Directives:
2014/30/EU
Electromagnetic Compatibility
2011/65/EU
Restriction of the use of certain hazardous substances
The Declaration of Conformity is available to download via:www.elcometer.com/images/stories/PDFs/Datasheets/Declaration of Conformity/English/DoC_138.pdf
This product is Class B, Group 1 ISM equipment according to CISPR 11.
Class B product: Suitable for use in domestic establishments and in establishments directly connected
to a low voltage power supply network which supplies buildings used for domestic purposes.
Group 1 ISM product: A product in which there is intentionally generated and/or used conductively
coupled radio-frequency energy which is necessary for the internal functioning of the equipment itself.
is a registered trademark of Elcometer Limited, Edge Lane, Manchester, M43 6BU.
United Kingdom
All other trademarks acknowledged.
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Please ensure that all packaging is disposed of in an environmentally sensitive manner. Consult yourlocal Environmental Authority for further guidance.

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