Any and all reproduction or transmission of any part of this manual, in any form or by any means
and for any purpose other than the personal use by the purchaser is strictly forbidden without the
express written authorization of Tinker & Rasor.
The Model M/1 Holiday Detector is a highly sensitive device designed to locate holidays (pin holes,
voids, etc.) in thin film protective coatings of relatively high electrical resistance when such films
are applied to the surface of material of low electrical resistance. In these applications, such as
painted metal surfaces, the Model M/1 Holiday Detector will locate these points very accurately
with an audible and visual signal. This method of inspection of thin film is a non-destructive test
and will not injure the protective coating.
EQUIPMENT
The Model M/1Holiday Detector consists of a portable battery powered electronic instrument, a
wand handle, and sponge assembly (open cell sponge ships compressed, will expand with water),
and ground wire. The instrument is housed in a sturdy plastic case with provision for attachment of
optional (not included) headphones.
The detector is a “non-destructive wet sponge” type holiday detector. The basic electronic design
of the Model M/1 Holiday Detector is that of a very sensitive circuit which is energized by one 9v
battery. When current of 500 or 700 (+/- 10/%) micro-amperes flows in the circuit, an audible and
visual signal is actuated.
The test lead wire used in the ground wire can handle a minimum of 100 milliamps at 100 volts. If
replacement or additional wire is needed, make sure it meets these requirements. Up to 100’ length
of ground wire does not adversely affect the detectors operation, in most cases. If adding additional
ground wire, 14 AWG stranded or equivalent is recommended.
The exploring electrode is open-cell sponge material and is conductive when saturated with a
wetting solution. The sponge electrode is attached to the non-conductive wand handle by means
of the bolt with knob, plastic sponge holder and backing plate.
a non-sudsing wetting agent, available in 8 oz. bottles, factory direct or through stocking
distributors.
PRE-ELECTRICAL TEST PROCEDURES
The protective coatings should be dry and free of all contamination prior to electrical holiday testing.
Proper curing and drying time of the protective coating must be established prior to conducting
electrical holiday testing.
Note: Solvents retained in the protective coating film can cause erroneous indications (false
holidays) during electrical testing.
The dry film thickness should not exceed 20 mils when electrical holiday testing is done with the
low voltage Model M/1Holiday Detector. Film thickness should be determined with a nondestructive dry film thickness gauge to make sure limits are not exceeded.
Special Note: Ordinary tap water will generally suffice to dampen the sponge electrode,
provided the protective coating thickness does not exceed 10 mils. The factory
recommended practice is to use a wetting agent at all times, regardless of coating
thickness up to 20 mils. The low voltage holiday detector is not recommended for coatings
greater than 20 mils of thickness.
Check battery voltage. This can be done by shorting the wet sponge with the bare end of the
ground cable of the holiday detector. If a steady, level audible signal is heard, the battery voltage
is OK. If the audible signal starts to attenuate while testing, REPLACE battery. Note: A battery
output voltage drop of over 10% also indicates weak battery.
HOLIDAY DETECTOR ASSEMBLY
Assemble the Holiday Detector by first connecting the ground cable to the handle. Insert the ground
cable connector into the handle, and then rotate one quarter turn counter clockwise to lock. Connect
the wand handle to the front (nose) of the instrument and screw down until firmly seated.
Attach the sponge bracket (aluminum piece), sponge, sponge holder (plastic piece) and the knob
with threaded bolt through all and screw down on the wand end. Saturate the sponge in a wetting
solution.
CHANGING THE BATTERY
The M/1 is powered by a replaceable 9v battery.
To access the battery, locate the BATTERY
ACCESS label on the main top panel of the
instrument. There are two (2) screws near the
handle that need to be removed. Once removed,
lift and rotate the BATTERY ACCESS door toward
the front of the instrument and remove. Replace
the BATTERY ACCESS door by hooking the latch under the mail panel and rotating back into
place. The latch will snap in and the BATTERY ACCESS door will sit flush when properly aligned.
The 9v battery is located inside the battery access area and is attached to a battery terminal
connector. The battery connecter can be removed by firmly grasping the battery with one hand and
the connector with the other and pulling apart. Do not use a screwdriver or any prybar made of a
conductive material to separate the battery from the connector.
When replacing the battery, observe polarity. The 9v battery has two terminals side by side. The
smaller terminal is the Positive (+) connection, as indicated on the battery (most batteries). The
larger terminal on the battery is Negative (-). When connecting the 9v battery to the battery
connector, ensure that the terminals are mating with the corresponding connector. If the battery
terminals do not snap into the battery connector terminals, the battery may be backwards.
ELECTRICAL TESTING PROCEDURES
The sponge electrode should contain sufficient amount of wetting solution to assure moisture
penetration from the sponge electrode into any defect that may be present in the protective coating.
Excess wetting solution should be squeezed out of the sponge electrode.
Attach ground wire directly to the bare structure (substrate) under test. On coated steel structures
the ground wire must be directly connected to the bare metal.
On coated concrete structures the ground wire should be connected directly to the reinforcing steel
embedded in the concrete. If rebar is not present, a ground connection to the concrete can be
made by placing the bare end of the ground wire against the bare concrete surface and anchor it
down with a burlap bag filled with damp sand.
The ground wire can be checked quickly for proper connection by contacting the wetted sponge
electrode to the bare structure and observing an audible signal, indicating correct electrical
continuity of the holiday detector circuit.
The rate of inspection speed of the sponge electrode over the protective coated surface should not
exceed sixty (60) linear feet per minute. Using a double stroke of the sponge electrode over each
area assures better inspection coverage with less likelihood of any missed areas.
CALIBRATION
Factory calibration on Model M/1 Holiday Detectors is set at 700 micro-amperes (+/- 10%) of current
flow to complete the circuit for the audible signal to indicate a coating holiday on metal substrates.
For coatings on concrete substrates, the Model M/1 must be adjusted for current flow of 500 microamperes (+/- 10%).
ADJUSTMENT OF SIGNAL SYSTEM
Model M/1 Holiday Detector sensitivity may be verified by simply depressing push buttons on the
front of the instrument. The instrument is Factory set for use on steel structures.
For use on steel structures, depress BLACK button (80K); Detector should signal and LED will
light if detector is in calibration.
Depress RED button (90K): Detector should NOT signal and LED will NOT light if detector is in
calibration.
If the detector signals when either the BLACK button (80K) or the RED button (90K) is depressed,
the unit is set for concrete structures. The adjustment is a small jumper setting on the main circuit
board.
If the BLACK button (80K) fails to signal, the instrument is not in calibration and should be sent for
Factory calibration.
ACCESSORIES
All accessories included with the instrument (page 1 list) are available for purchase, including
additional sponges. Sponge electrodes are available in standard size, as included with new
instruments, or as custom size widths, or as disks for internal pipeline coatings. Contact T&R for
details.
The Wand with Cable Adapter has been added to the new style M/1 to allow customers to continue
to use the M/1 as it was in its previous form. The unit can be secured using the belt loop on the
side of the case when using the Wand with Cable Adapter.
The M/1 can use optional headphones for loud/noisy environments. Headphones are available for
purchase from Tinker & Rasor or many standard headphones with 3.5mm jack will work with the
M/1.
FACTORY REPAIRS
Holiday Detectors returned to the factory for repairs should be sent TRANSPORTATION PREPAID.
In most cases the detector can be repaired and returned the same day it is received at the factory.
WHEN ORDERING PARTS FOR YOUR DETECTOR OR REQUESTING FURTHER
INFORMATION ALWAYS GIVE THE DETECTOR’S SERIAL NUMBER.
Visit www.tinker-rasor.com/repair for shipping information and the Repair Form
The electrical holiday detector commonly used for inspection for brushed, sprayed or dip-applied
protective coatings is considered a non-destructive device with a source of less than 75 volts
applied to the coatings using an electrode consisting of a cellulose sponge dampened with an
electrically conductive liquid such as tap water. The electrode pushes a film of liquid over the
surface and when a holiday is encountered, current will flow through the liquid to the metal. An
audible indicator is used to signal coating defects.
Recommended points to be included in a specification for the electrical inspection of thin film
coating with the so-called “non-destructive” type holiday detector, Tinker & Rasor Model M/1 are:
1. The voltage between the electrode (sponge) and the metal surface upon which the coatings
lies should not exceed 75 volts measured between the electrode sponge and the coated
metal when the detector is in its normal operating position.
2. An electrical connection must be made from the detector to some bare spot on the metal
structure to be coated.
3. The holiday detector should be equipped with an audible signal which is responsive to high
current flows between electrode and the metal surface.
4. The coated surface should be dry prior to making the inspection and if the surface is in an
environment where electrolytes might form on the surface such as salt spray, the coated
surface should be washed with fresh water and allowed to dry.
The consensus of the industry is that ordinary tap water will suffice to wet the sponge electrode
when this type of electrical holiday inspection is conducted on protective coatings up to 10 mils in
thickness. On film thickness between 10 and 20 mils a non-sudsing type wetting agent added to
the water is recommended. This allows for faster penetration of the liquid into pinhole defects. A
wetting agent such as TINKER & RASOR’S“WATER-WETTER” is an excellent product for this
purpose. Available in 8 ounce size bottle.
It is further agreed that this type holiday detector is not satisfactory for inspection of protective
coatings over 20 mils in thickness and completely ineffective on prefabricated coatings such as
PVC, etc.
An electrical holiday detector should be used at the time the coating is applied. The holiday detector
should never be used to evaluate the quality or usefulness of a coating and should be used only
as an aid in the application of the coating. When the detector is used at the time of application,
holidays can be readily located and repaired. The detector not only locates holidays, but it enables
the applicator to develop techniques of better application.