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Adhesives

3M™ Scotch-Weld™ structural adhesives for aerospace manufacturing and MRO — engineered, epoxy, hot melt, film, and foaming adhesive systems trusted across every major aircraft OEM program. The most comprehensive structural adhesive portfolio in aviation, from room-temperature paste adhesives to high-performance film adhesives curing at 350°F. 

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Coast-Line stocks 3M™ Scotch-Weld™ adhesives — the aerospace industry standard across five product families covering every bonding application from structural paste adhesives and freeze-stable film adhesives to core splice films, hot melt systems, and foaming void-fill compounds. 3M™ maintains partnerships with every major aircraft OEM. 

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Film
Thermosetting epoxy in film form. Uniform bondline, freeze-stable storage, for structural metal/composite/honeycomb bonding.
Foaming
Low-density expanding adhesives for honeycomb core splicing, void filling, edge close-out, and gap filling.


Engineered
Specialty systems for contact bonding, sealant primers, and surface prep adhesion promoters.


Epoxy
Two-part paste adhesives — room-temperature or heat cure. For metals, composites, glass, ceramics, and plastics.


Hot Melt
100% solids thermoplastic adhesives applied via gun. Fast bonding, no mixing, shock and vibration resistant.


01

Film Adhesives

Film Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ Structural Adhesive Film AF 163-2
The most widely used 3M structural adhesive film in aerospace — a thermosetting modified epoxy film providing high fracture toughness and peel strength across a broad range of environmental conditions. AF 163-2 is a family of films available in multiple weights (0.03, 0.06, 0.08, 0.10 psf) and with or without supporting carriers (knit, matte). Bonds composites, metals, and honeycomb sandwich constructions for both solid panel and sandwich applications. Cures from 180°F to 350°F. Freeze storage required (−18°C / 0°F). Available with a non-woven matte carrier (AF 163-3M) for enhanced handling and positioning. Excellent pre-bond humidity performance on composite substrates.
Most Widely Specified Film −67°F to 250°F Service Freeze Storage −18°C High Fracture Toughness Multiple Weights & Carriers BMS 5-101 · OEM Qualified
AF 163-2 Family
Service Temp−67°F to 250°F (−55°C to 121°C)
Cure Range180°F to 350°F
StorageFreeze at −18°C / 0°F
Available Weights0.03 · 0.06 · 0.08 · 0.10 psf
Carrier VersionsKnit (K) · Matte (M) · Unsupported
SubstratesMetal · Composite · Honeycomb
Bell299-947-121
Bell299-947-320
BoeingBMS 5-129
BoeingBMS 5-101
Sikorsky/LMSS8612
Description
3M™ Scotch-Weld™ Structural Adhesive Film AF 163-2 is a family of thermosetting modified epoxy adhesives in film form, engineered for the long-term durability demanded by metal and composite solid-panel and honeycomb sandwich construction. It pairs naturally with AC-130: once the bond surface is pre-treated, the film provides a clean, uniform, metered bondline with high fracture toughness and peel strength.

The film is available in a range of weights and carrier types (knit-supported, mat-supported, and unsupported for reticulation) so the bondline can be matched to the application without carrying excess material cost. It is designed for a 250°F (121°C) cure and can be processed from roughly 180°F up to 300°F, and exhibits excellent pre-bond humidity performance on composite substrates. Compatible 3M™ structural bonding primers include EW-5000, EW-5000 AS, EC-3917, and EC-3924 B.
Key Benefits
High fracture toughness and peel strength across a broad service range, -67°F to 250°F (-55°C to 121°C)
Pairs directly with AC-130 surface pre-treatment for a complete prep-to-bond process
Suitable for composites, metals, and metal-to-honeycomb solid panel and sandwich fabrication
Excellent pre-bond humidity performance on composite substrates
Excellent shop-handling characteristics — clean, uniform application with reduced mess vs. paste
Available in multiple weights and carriers; unsupported version available for reticulation
Compatible with multiple substrates and 3M structural bonding primers
Technical Data
TypeThermosetting modified epoxy film adhesive
SubstratesMetals, composites, honeycomb sandwich
Service Temperature-67°F to 250°F (-55°C to 121°C)
CureDesigned for 250°F (121°C); processes ~180°F–300°F
CarriersKnit-supported, mat-supported, or unsupported
Compatible PrimersEW-5000, EW-5000 AS, EC-3917, EC-3924 B
Related ProductsAF 163-2K, AF 163-2M, AF 191, AF 191XS
Available Formats
.030 wt
Lightweight bondline
.045 wt
General purpose
.060 wt
Heavy bondline
Custom
Roll widths & lengths
Film Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ Structural Adhesive Film AF 191
High-temperature structural adhesive film for demanding aerospace applications requiring elevated temperature performance — bonds from −67°F to 350°F (−55°C to 175°C), providing 125°F more service capability than AF 163-2. Thermosetting modified epoxy with high fracture toughness, peel strength, and outstanding environmental durability. Available in supported (knit carrier) and unsupported versions for reticulation onto honeycomb. Part AF 191K .08 features a nylon knit carrier and cure flexibility from 275°F to 350°F. Qualified to multiple OEM specs including A50TF272-S7.
High Temperature — 350°F −67°F to 350°F Service Nylon Knit Carrier (K) A50TF272-S7 · OEM Qualified Freeze Storage
Film Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ AF 3109-2K — Low-Pressure Cure Film
Thermosetting modified epoxy structural adhesive film engineered for low-pressure curing with minimal volatile by-products — ensuring clean, consistent bonds in production environments where autoclave pressure or high bag pressure may not always be achievable. AF 3109-2K .085 psf is designed for bonding composite laminates and sandwich structures where consistent adhesive distribution and reliable processing across complex geometries is critical. Qualified to multiple aerospace OEM specifications.


Low-Pressure Cure Minimal Volatiles 0.085 psf Weight Complex Geometries Freeze Storage
Product 04 For Surface Treatment & Paint Prep
3M™ Scotch-Weld™ Composite Surfacing Film AF 325 LS
Low-density thermosetting epoxy surfacing film that co-cures as the outermost ply of a composite layup — producing a smooth, void-free, pinhole-minimized surface that is ready for paint. The surface-treatment companion to AC-131, with conductive options for lightning-strike protection.
Surface Treatment Composite Surfacing Pre-Paint Ready White or Blue Lightning-Strike Options
Description
3M™ Scotch-Weld™ Composite Surfacing Film AF 325 LS is a low-density, thermosetting epoxy film applied as the outermost layer of a composite part. Co-cured with the layup, it produces a smooth, void-free surface with minimal pinholes — significantly reducing the fill, fairing, and sanding normally required before paint. Where AC-131 prepares metal for coating, AF 325 LS prepares the composite surface, completing Coast-Line's surface-treatment offering across both substrate families.

It delivers excellent temperature-range performance from -67°F to 300°F (-55°C to 149°C) and is co-cure compatible with most epoxy prepreg systems at both 250°F (121°C) and 350°F (177°C). Available in white and blue to provide visual contrast against the underlying prepreg for coverage verification. For lightning-strike protection and EMI shielding, conductive variants such as AF 191XS and AF 536 incorporate a lightweight conductive mesh in the outer ply.
Key Benefits
Smooth, void-free surface with minimal pinholes — reduces fill, fairing, and sanding
Low-density formulation aids pre-paint surface preparation and reduces weight
Co-cure compatible with most epoxy prepreg systems at 250°F and 350°F
Broad service range, -67°F to 300°F (-55°C to 149°C)
White or blue for color contrast against prepreg — easy coverage verification
Conductive variants (AF 191XS, AF 536) provide lightning-strike protection and EMI shielding
Completes the surface-treatment line alongside AC-131 for metallic substrates
Technical Data
TypeLow-density thermosetting epoxy surfacing film
FunctionOuter-ply composite surfacing / pre-paint prep
Service Temperature-67°F to 300°F (-55°C to 149°C)
Co-Cure CompatibilityMost epoxy prepregs at 250°F & 350°F
ColorsWhite or Blue (contrast against prepreg)
Lightning StrikeConductive options: AF 191XS, AF 536
Related ProductsAF 325 M, AF 191XS, AF 536
Version Selection
AF 325 LS · White / Blue
Non-conductive surfacing film for a smooth, paint-ready finish. Color contrast against the prepreg confirms complete coverage during layup.
AF 191XS / AF 536 · Conductive
Surfacing film with an integrated lightweight conductive mesh for lightning-strike protection and EMI shielding on exterior composite structures.

Film Adhesive Storage — Freeze Required

All 3M Scotch-Weld™ structural adhesive films (AF 163-2, AF 191, AF 3109-2K) require frozen storage at −18°C / 0°F. Coast-Line maintains proper freeze storage for all film adhesive inventory. Out-time (time at room temperature before cure) must be tracked. Contact us to discuss program planning for out-time management and delivery scheduling.

02

Foaming/Filler Adhesives and Void Fillers

A New Approach to Core Splice

3M™ Scotch-Weld™ Core Splice Adhesive Film AF 3074 FST

This epoxy-based, low-density splice film can be stored and transported unfrozen for up to six months, and its high and repeatable expansion rates deliver reliable consistency across individual assemblies and entire jobs. The result: more flexible production planning, faster production and reduced weight per part.

  • Repeatable expansion rates add consistency to the parts
  • Low density of 0.4 g/cm³ @ free expansion
  • Less sensitive to heat and humidity
  • Less cold flow keeps cut edges smooth and gloves clean
  • Up to six months shelf life and shop life at room temperature
  • Enables non-refrigerated transport
  • Classified non-dangerous good – can be transported by air
  • Co-curable film is compatible with 120°C and 180°C cure cycles withwide service temperatures from -55°C up to 135°C

Applications for core splicing and reinforcement:

  • Primary and secondary structures
  • Interior monuments
  • Engine nacelle
Foaming Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ Structural Core Splice Film AF 3024
The industry standard for honeycomb core splicing — a low-density, thermally expanding core splice adhesive film with 250% expansion rate. Designed specifically for filling mismatch areas and splicing honeycomb core sections in aerospace sandwich structures. The 250% expansion ensures successful joining of significantly mismatched honeycomb structures that would not be bridgeable with a standard non-foaming film. Low sag during cure eliminates the need for rework. Cures from 250°F to 350°F. High performance from −67°F to 350°F. Low volatile loss during cure. Even at slow heat-up rates as low as 0.5°F/minute, AF 3024 still reaches full expansion. Qualified to A50TF103-S8 and STM 30-301 Type IIIB.
Industry Standard Core Splice 250% Expansion Rate Low Sag During Cure −67°F to 350°F A50TF103-S8 · STM 30-301 Freeze Storage
AF 3024 Key Data
Expansion Rate250% (highest in class)
Cure Temp Range250°F to 350°F
Service Temp−67°F to 350°F
Min Heat-Up Rate0.5°F/minute (full expansion)
VolatilesLow loss during cure
StorageFreeze at −18°C
Foaming Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ Core Splice Adhesive EC-3500 B/A
Two-part, modified epoxy paste adhesive for core splicing, filling mismatched areas, and reinforcing honeycomb core. Low-density formula with low volatile loss during cure. Long work life for large assemblies. High shear and compression strength maintained even at high temperatures. Performance from −67°F to 350°F. Available as standard B/A two-part, as 3500-2 (updated formulation), and as PMF (Pre-Mixed and Frozen) for ready-to-use application without mixing on the shop floor. Used for edge close-out on interior honeycomb sandwich, corner reinforcement, and local reinforcement for mechanical fasteners.
Two-Part Paste Core Splice Low Density −67°F to 350°F PMF Version Available Edge Close-Out
Foaming Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ EC-3500-2 PMF — Pre-Mixed & Frozen
Pre-Mixed and Frozen (PMF) formulation of the 3500-2 void-filling compound — pre-mixed at the factory, frozen for storage, and ready to use after thawing without any mixing on the shop floor. Eliminates mix ratio errors and reduces preparation time. Heat-curing, low-density epoxy-based compound for structural void filling. Ideal for edge close-out, corner reinforcement, complex gap filling, and local reinforcement for mechanical fasteners in honeycomb sandwich structures. High performance from −55°C to 175°C (−67°F to 347°F). Qualified to IPS 10-03-002-01 and MSRR9150.
Pre-Mixed — No Mixing Errors Frozen Ready-to-Use −67°F to 347°F IPS 10-03-002-01 · MSRR9150 Freeze Storage
03

Engineered Adhesives

Engineered Adhesive
3M™ · Scotch-Weld™
3M™ Scotch-Weld™ Contact Adhesive EC-1300L — Neoprene
A neoprene-based solvent contact adhesive for bonding rubber, gaskets, plastics, wood, and metals. One of the most widely used contact adhesives in aerospace MRO — applied to both surfaces, allowed to dry, and bonded on contact for instant holding strength. Fast drying, heat resistant, and provides high-strength bonds suitable for MRO and AOG situations. Used for attaching acoustic insulation, floor coverings, seating foams, rubber seals, and other interior components. Available in tin and bulk formats.
MRO Contact Adhesive Neoprene Solvent Rubber · Gaskets · Plastics Interior Components Contact Bond — Instant Tack
Key Properties
ChemistryNeoprene solvent-based
Bond MethodContact (apply to both surfaces)
Heat ResistanceGood for interior temperatures
SubstratesRubber, gaskets, plastics, wood, metals
ApplicationsInsulation, seating foam, seals
PackagingTin (0.95 L), bulk formats
Engineered Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ Adhesive Primer EC-3924 B
Corrosion-inhibiting adhesive primer providing high-degree protection against corrosive environments both inside and outside the adhesive bondline. Epoxy-based synthetic resin primer formulated for use under 3M structural film adhesives — ensures maximum bond strength and durability on metal substrates in structural aerospace assemblies. Qualified to multiple aerospace OEM specifications including 299-947-320 Class I, 299-947-121 Class III, and STM 30-102 Type II Grade A.
Bondline Corrosion Inhibitor 299-947-320 · STM 30-102 Pre-Film Adhesive Primer Epoxy Resin
Engineered Adhesive
3M · Scotch-Weld™
3M™ EC-3524 B/A Void Fill & Edge Sealing Compound
Fire retardant, void filling, edge-sealing, potting, and complex gap-filling epoxy compound for aerospace weight reduction. Non-sag — applies to multiple work pieces simultaneously without sagging. Sandable within 3 hours at room temperature. Available in blue, off-white, and black. Shelf-stable — no freezer storage required. Used in galleys, luggage bins, partition walls, lavatories, seating, ceiling panels, floorboards, passenger doors, and as an abradable compound in engine nacelles.
Non-Sag Paste Sandable in 3 Hours Edge Sealing & Void Fill Fire Retardant No Freezer Storage
04

Epoxy Adhesives

Epoxy Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ Epoxy Adhesive EC-2216 B/A
The most widely specified 3M aerospace epoxy adhesive — a flexible, two-part, room-temperature curing epoxy providing high shear and peel strength for the most demanding aerospace applications. Outstanding for cryogenic bonding (maintains bond strength to −423°F / −252°C). Mix ratio 2:3 (B:A). Work life 90 minutes at room temperature — allowing repositioning and adjustment. Full RT cure in 7 days; can be heat-cured in 30 minutes at 200°F. Overlap shear strength up to 3,200 psi at 72°F. Bonds metals, plastics, honeycomb to aluminum, composites. Available in duo-pak cartridges with 3M EPX™ Applicator for precise dispensing and minimal waste. Aerospace grade: EC-2216 B/A.
Most Widely Specified 3M Epoxy Two-Part Room-Temp Cure Cryogenic to −423°F 3,200 psi Shear Strength 90 Min Work Life Duo-Pak / EPX™ Cartridge
Key Specs
ChemistryFlexible epoxy — 2 part
Mix Ratio2:3 (B:A)
Work Life (RT)90 minutes
Full RT Cure7 days · or 30 min @ 200°F
Shear Strength~3,200 psi @ 72°F
Cryogenic Rating−423°F (−252°C)
Epoxy Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ Structural Epoxy EC-9323 B/A
Toughened two-component epoxy paste adhesive curing at room temperature or with mild heat — forms a tough, impact-resistant structural bond. Excellent adhesion to metals, glass, ceramics, and plastics including GFRP and CFRP. Extremely high shear and peel strength over a wide temperature range. Outstanding resistance to harsh environments and chemicals encountered in aerospace. Gels in 3 hours, handling strength in 4–5 hours, full RT cure within 14 days. Shelf life 12 months in original containers at room temperature.
Toughened 2-Part Epoxy RT or Mild Heat Cure GFRP · CFRP Compatible Impact Resistant 3-Hour Gel Time
Epoxy Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ EC-9323-2 B/A — Sag-Resistant
Thixotropic, sag-resistant version of EC-9323 — the paste stays where applied even on vertical and overhead surfaces without running or draping before cure. Two-component epoxy curing at room temperature or with mild heat to form a tough, impact-resistant structural bond. Maintains all the shear, peel, and chemical resistance properties of EC-9323 with the addition of non-sag behavior critical for bonding in overhead or vertical assembly positions.




Thixotropic — Non-Sag Vertical & Overhead Bonding Impact Resistant RT Cure
05

Hot Melt Adhesives

Hot Melt Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ Hot Melt Adhesive 3748 — General Purpose
A 100% solids thermoplastic hot melt adhesive for general-purpose bonding — no mixing, no solvents, no hazardous waste. Applied with the 3M Scotch-Weld™ Hot Melt Applicator in stick form (PG, TC, or Q sizes). Provides a strong, flexible bond with excellent shock and vibration resistance — uniform bond line distribution minimizes stress concentration compared to mechanical fasteners. Good thermal shock resistance and excellent bond to polyolefins. Used for bonding components in aerospace interior assembly, electronics, and general-purpose applications. The 3748 VO (Flame Out) version is self-extinguishing (UL 1410 compliant) for fire-sensitive aerospace interior applications.
100% Solids — No Solvents Hot Melt Gun Application Thermal Shock Resistant Vibration Resistant 3748 VO — Self-Extinguishing UL 1410 (VO version)
Key Properties
Chemistry100% solids thermoplastic
ApplicationHot melt gun (PG / TC / Q sticks)
Bond TypeFlexible — shock & vibration
Polyolefin BondExcellent
VO VersionSelf-extinguishing (UL 1410)
Mixing RequiredNone
Hot Melt Adhesive
3M · Scotch-Weld™
3M™ Scotch-Weld™ Hot Melt Adhesive 3748 VO — Flame Out
The self-extinguishing version of 3M Hot Melt 3748 — meets UL 1410 flammability requirements, making it the preferred choice for aerospace interior applications where FAR 25.853 or similar fire certification is required. Same 100% solids thermoplastic construction, shock and vibration resistance, and excellent polyolefin adhesion as the standard 3748 but with a non-burning formulation that self-extinguishes when the combustion source is removed.




Self-Extinguishing UL 1410 Compliant Aerospace Interiors FAR 25.853 Compatible

Why Source 3M Scotch-Weld™ from Coast-Line?

Freeze Storage Capability

Coast-Line maintains proper −18°C freeze storage for all film adhesive and frozen compound inventory, ensuring material is in-specification upon delivery.

Authorized 3M Distributor

Genuine 3M Scotch-Weld™ products with full 3M traceability. Certificate of Conformance available on all aerospace-grade products.

OEM Spec Support

3M maintains spec qualifications with every major aircraft OEM. Our team can help identify the correct product number based on your specification.

Technical Support

Adhesive selection for specific substrates, cure conditions, or OEM specifications — our team can guide you through the 3M aerospace adhesive portfolio.