FM® 385 - adhesive film was developed specifically for bonding composite and metallic structures for nacelle applications. It provides a unique combination of high Tg, toughness, and flatwise tensile properties.
FM® 385 is compatible with most 350°F (177°C) curing epoxy-based prepreg systems. It has excellent resistance to pre-bond and post-bond humidity and has a dry service temperature of 420°F (216°C).
FM® 385 adhesive film provides excellent handling properties (good tack and drape) and has a minimum shop life of 30 days at 75°F (24°C).

FM® 385 adhesive can be supplied as a supported (woven glass or mat carrier) or unsupported film at various weights and thicknesses. For co-cure or co-bond applications, adhesive film weight of 0.060 lb/ft2 – 0.080 lb/ft2 (293 gsm – 391 gsm) with woven glass or a glass mat carrier is recommended. This adhesive film is suitable for bonding of monolithic or sandwich structures. Honeycomb sandwich panels manufactured using FM® 385 adhesive film demonstrate excellent laminate quality (void content <1%) and very good filleting.

FM® 385 adhesive film can be cured at 350°F (177°C) in 90 minutes at 40 psi (0.28 MPa) or can be cured under vacuum-only pressure. Mechanical performance of vacuum-only cure is comparable to autoclave pressure cure.

Solvay recommends using BR® 6750 (chromated) or BR® 6700 (non-chromated) water-based primers for metal bond applications using FM® 385 adhesive film. For higher temperature applications or continuous service at 350°F (177°C), higher Tg BR® 6800 (non-chromated) water-based primer is recommended.

Typical applications for FM® 385 include co-cure, co-bond and secondary bonding of metallic and composite structures for nacelle applications. Additional applications include honeycomb sandwich structures.

Features and Benefits 
  • Excellent fracture toughness (co-cure, co-bond or secondary bond) 
  • Service temperature of 420°F (216°C) dry and 300°F (149°C) wet 
  • Excellent resistance to both pre-bond and post-bond humidity 
  • Good combination of peel and shear properties 
  • Tg > 375°F (191°C) 
  • Designed for bonding composite sandwich structures (good filleting properties) 
  • Unsupported film designed for reticulation for acoustic structures 
  • Highly flow controlled, good tack and handling properties 
  • Shop life > 30 days at 75°F (24°C) 
  • Compatible with most 350°F (177°C) curing epoxy prepregs


  • Global Business Unit
    Composite Materials
  • Brand
  • Synonyms
    fm385; adhesive film; fm 385


Segments Applications
Airframe Secondary structural materials | Primary structural materials

Chemical categories

Chemical category Chemical family Chemical product
Composites Thermoset Epoxy
Process Materials Release Fabric Modified glass fabrics

Region of commercial availability

  • Asia / Pacific
  • Europe / Middle East / Africa
  • North America
  • Latin America

Download documentation for FM 385