Echo 8 HT™ is a line of high temperature, slow drying fluid ultrasonic fluids with an excellent safety profile and is compatible with all metals and most plastics.

Echo 8 HT™ High temperature ultrasonic coupling fluids are available in four viscosities; Grades 1, 4, 6 and 10.  Performance of a broad range of AUT and MUT ultrasonic flaw and thickness gaging applications from -50°F to 800°F (-45°C to 425°C) is possible with these four grades.

Grade 1 is the lowest viscosity fluid (100 cST) for long or small diameter lines and quick spreading.

Grade 4 is Echo’s standard viscosity fluid (400 cST) and is usually a good compromise between pump ability and run-off at the transducer.

Grade 6 is a higher viscosity fluid (850 cST) that minimizes run-off at the transducer, however, requires system “pump ability” testing.

Grade 10 is a very thick fluid (5,000 cST – honey like) for MUT.  It spreads easily over large hot surfaces, stays in place and leaves minimal, if any residue.

All grades of Echo 8 HT provide excellent corrosion inhibition on ferrous metals, leave minimal residue and are compatible with all metals and most plastics.

Echo 8 HT has low toxicity and is essentially non-irritating


  • Auto Ignition Temperature:820°F (437°C)
  • Sound Velocity: 4900 ft/sec (1494 meters/sec)
  • Viscosity: ≈ 400 cps
  • Halogens and Sulfur:
  • Specify Gravity: 1.07
  • Weight/gallon: 8.91 pounds/4.04 kg net

Echo 8 HT