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NDT Couplant

Silver Bullet Couplants – for inspections that are almost impossible without the right couplant.

Many UT applications require a specialty UT couplant.  For difficult inspections that require high acoustic impedance, shear wave, reduced surface noise, extreme temperature range or extended service life for sensors, we have the right couplant.

High Impedance Couplant: A high impedance couplant typically has an acoustic impedance above 3.5 M Rayls.  Water based couplants typically have acoustic impedances between 1.5 and 1.8 M Rayls depending on the Glycerin content (0% glycerin at 1.5 M Rayls, 12% glycerin at 1.8 M Rayls, 100% glycerin at 2.4 M Rayls). 

The advantage of a high impedance couplant is that more of the acoustic energy is transmitted between the transducer (or delay line) and test object and less is reflected and scattered at the surface of the test object.  This is particularly important when:

  • The test object surface is very rough (porous cast iron, scale, rough grinding).
  • The contact area for the delay line or transducer is small (pencil point probes measuring pit depths).
  • Materials such as concrete which are high impedance, scatter acoustic energy and often have a rough surface.

There are currently two options for water-soluble, high impedance couplants:

  • Z+ MV, a medium viscosity Glycerin based couplant (which has an operating range of 0 to 200°F; however, its viscosity increases quickly with temperature below 45°F.
  • Z+ fluid– does not contain Glycerin and maintains a fluid viscosity down to sub-zero temperatures.

Normal Incidence Shear Wave Couplant:

Not to be confused with angle beam generated shear waves (which rely on refraction of a longitudinal beam), normal incidence shear wave transducers propagate the shear wave with the transducer perpendicular to the test object and do not rely on refraction.  A normal incidence shear wave couplant requires a very high viscosity, high elastic modulus to perform acceptably.  Currently there is one commercially available water-soluble couplant that meets this requirement: Echo Shear Wave Couplant

Flow Meter and Sensor Couplant:

For permanent or long-term use, a flow meter couplant should resist creep, have good resistance to weather and chemicals as well as a broad temperature range.  Water-based couplants are suitable only for short-term flow metering applications. Echo 8 ZH is not water-based and is an excellent couplant for flow metering sensors.

Cryogenic UT Inspection:

CryoSoniX is the only ultrasonic couplant for use in cryogenic applications such as refrigerated ethylene. With an operating range of -200˚ to 60˚F (-129˚ to 16˚C), CryoSoniX enables repeatable and reliable inspections.

Phased Array Wedge Couplant:

Forever Wedge is an ideal couplant for use between phased array or angle beam transducers and the wedge.  Forever Wedge couplant won’t leach out, is impervious to water and couplants and when applied correctly, often lasts the life of the wedge or until it is replaced.  Forever Wedge eliminates phased array element drop out due to wedge couplant failure.

Open top, rigid 1-gallon pail

1-Gallon Pail

We now offer our couplants in a 1-gallon, open top rigid pail.  Ideal for applications where couplant is painted on a part.  Metal handle on the pail for convenient carrying.  UltraSoniX, EchoTrack, SoniX and VersaSonic now available.  Call or e-mail for more information and pricing. (360) 6719121,


Winterized ECONOgel UT Couplant

Economically inspect in severe weather with Winterized ECONOgel™. Winterized ECONOgel ultrasonic couplant has been optimized for performance between 0° and 150°F. Available in 55-gallon drums. Winterized ECONOgel is a low/medium viscosity gel ideal for spreading or painting. This salt-stable couplant has good corrosion characteristics and is cost effective at $595/drum.

Standard ECONOgel performs from 26° to 120°F, and is the lowest cost cellulose couplant.ECONOgel-ultrasonic-couplant

ECONOgel’s reduced surface tension provides fast wetting.

ECONOgel is glycerin and silicone free.

ECONOgel has good ferrous corrosion inhibition and is compatible with most metals, plastics and composites.

ECONOgel is completely salt stable. It will not thin with corrosion salts, marine environments or highway infrastructure subjected to de-icing salts.

Environmental and operator friendly. No formaldehydes or nitrates or nitrites.

For free samples and additional information, visit

New Couplants Introduced at ASNT

Ask us about our four new couplants at booth 205 at the ASNT Annual Convention in Salt Lake City, UT.  EchoTherm and EchoTherm Extreme are the first high temperature ultrasonic couplants with an auto-ignition temperature above 1300°F.  EchoPure is ideal for very cold and very warm inspections and is a water-free yet water-soluble couplant.  EchoMix Powder is now available as a one part packet. 

Introducing EchoTrack™ a new high performance, economical ultrasonic couplant,


Echo Ultrasonics® has introduced EchoTrack™ ultrasonic couplant, an economical high performance ambient temperature ultrasonic couplant for flaw inspection and thickness gauging.  EchoTrack is compatible with most materials, has excellent ferrous corrosion inhibition and is formaldehyde and glycol ether free.  

EchoTrack has a broad operating range (18 to 180°F, -8 to 82°C), leaves a low level, easier to remove residue, is slow drying and is available in a medium and high viscosities.

For free samples, complete the sample request form and let us know what couplant you are currently using.

Explore the new Echo Ultrasonics® website to learn more about our line of industrial ultrasonic couplants with superior performance and fair pricing.

We have been developing and manufacturing ultrasonic couplants for over 50 years. Our founder has formulated most of the NDT couplants commercially available in the United States, including Exosen®, Ultragel II®, Echogel®, Pyrogel®, Sonotrace®, SoundSafe®, SoundClear®, Humex®, UT-30®, UT-X®, Sono® 600, Sono® 950, and Sono® 1100.

Our industrial ultrasonic couplant history began in Pennsylvania in the early 1960s. A lot has changed over the years, including information about operator and environmental safety as well as the availability of new, safer chemicals. With each company, founder Gene Larson has focused on optimizing product performance, improving the chemical safety profile and increasing the operating limits.

Echo Ultrasonics® offers custom formulations and packaging options as well as metallurgical and physical testing. If you have an application that isn’t being met with your current couplant, or you are looking for a superior product at a fair price, call us.

At Echo Ultrasonics, we take pride in the quality, safety and performance of our couplants. Our goal is to exceed your expectations!

Exosen is a registered trademark of GE Inspection Technologies.  Ultragel II, Echogel, Pyrogel, Sonotrace, SoundSafe, SoundClear, Humex, UT-30, UT-X and Sono 600, 900 and 1100 are registered trademarks of Magnaflux.