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Precision Acoustics

Aptflex F13

A two-part, high performance encapsulation material, exhibiting excellent hydrolytic stability and an acoustic wave speed similar to that of fresh water.

If you have any specific questions about this product, please contact us.

aptflex f13 with sample


Aptflex F13 is a flexible, high-performance encapsulation material, exhibiting excellent hydrolytic stability and an acoustic wave speed and acoustic impedance similar to that of fresh water. It provides a compromise between toughness and flexibility and is visually clear

These properties make Aptflex F13 an ideal system for hydrophone potting, or the encapsulation of marine electronics, especially when subsequent visual inspection is required.

It is particularly useful where small, delicate components are being potted since the material exhibits low shrinkage and hence stress during the cure phase.

Key features

  • Flexibility and resistance to temperature extremes of -50 °C to 100 °C
  • Low moisture sensitivity during the cure phase
  • Excellent hydrolytic stability
  • Excellent electrical insulation properties
  • Acoustic impedance and wave speed similar to that of freshwater
  • Low insertion loss and absorption

Technical specifications

Appearance Natural (straw colour)
Density part A 0.91 g/ml
Density part B 1.22 g/ml
Mix ratio 4:1 (By Weight A:B)
Cured density 0.96 g/ml
Initial mixed viscosity 50 poise at 25 °C
Usable life 25 minutes at 25 °C
Gel time 50 minutes at 25 °C
Curing times*: 24 to 48 hours at 25 °C
7 to 10 days
24 hours at 50 °C
16 hours at 80 °C
Hardness 65 to 70 Shore A
Tensile strength 5.5 MPa
Elongation at break 300%

* Curing times are temperature dependant. Precision Acoustics reserves the right to change the specification without notice.

** Minimum order quantities apply if there is no stock or if longer expiry dates are required.

The shelf-life of unopened containers is at least 12 months.


This product is subject to Dangerous Goods Movement control.

Please note this will typically incur an additional £270.00 surcharge for shipments