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Surface Prep Products for Bonding

3M™ sol-gel surface pre-treatments for adhesive bonding of aluminum, steel, titanium, and composite structures. Non-chromated, water-based alternatives to traditional phosphoric acid anodizing — with equivalent or better bond performance.

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Coast-Line stocks both 3M™ Surface Pre-Treatment AC-130 and AC-131  — the aerospace industry’s leading sol-gel surface preparation systems. Both are non-chromated, water-based alternatives to traditional processes like phosphoric acid anodizing (PAA), sulfuric acid-sodium dichromate etchings, and Grit Blast Silane. Qualified to major OEM specifications. 

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Tell us what you need and our team will respond within one business day with pricing and availability.

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Traditional Processes
Phosphoric Acid Anodizing (PAA)
Sulfuric acid-sodium dichromate etch
Grit Blast Silane (GBS)
Hazardous waste — special disposal
Requires heated tanks / facility
No field repair capability
VS
3M™ Sol-Gel (AC-130 / AC-131)
Water-based, non-chromated
Equivalent or better bond performance
35%+ reduction in labor time
Minimal hazardous waste
Ambient temperature cure
Field repair capable — reduces AOG time
Product 01 For Adhesive Bonding
3M™ Surface Pre-Treatment AC-130
High-performance sol-gel surface preparation for structural adhesive bonding of aluminum alloys, steel, titanium, and composites. The industry benchmark for metal-to-metal and composite-to-metal bond preparation — reducing process time by a minimum of 35% vs. PAA.


Structural Bonding Aluminum · Steel · Titanium Composites Non-Chromated BMS5-162 · BMS10-128
Description
AC-130 is a two-part, water-based sol-gel system designed to improve adhesion between metal and composite surfaces prior to bonding with aerospace-approved adhesives and primers. The chemical interaction between the substrate, AC-130, and the primer creates a durable, moisture-resistant bond that performs comparably to phosphoric acid anodizing (PAA) — without the hazardous waste, heated tank infrastructure, or special disposal requirements.

Applied by brush, spray, dip, or wipe. Cures under ambient conditions — no oven or autoclave required. Bond primer or adhesive must be applied within 24 hours of treatment application. Ideal for both production bonding and AOG field repair scenarios.
Key Benefits
Minimum 35% reduction in labor time vs. PAA, PACS, Grit Blast Silane, and PANTA processes
Allows multiple metallic substrates to be prepared with a single unified process
Ambient temperature cure — enables field repairs and reduces Aircraft on Ground (AOG) time
Mechanical performance comparable to PAA-prepared surfaces
Reduces hazardous waste — good alternative to acid paste etches and phosphoric acid containment systems
Qualified to BMS5-162, BMS10-128, and multiple OEM specifications
Technical Data
TypeTwo-part water-based sol-gel
SubstratesAluminum alloys, steel, titanium, composites
ApplicationBrush, spray, dip, or wipe
CureAmbient temperature — min. 60 min dry time
Open TimeApply primer/adhesive within 24 hrs
Chromate-FreeYes — non-chromated
SpecificationsBMS5-162, BMS10-128
Application Steps
1
Solvent clean the bond area to bare metal. Remove all coatings, adhesive residue, and contaminants.
2
Grit blast the bond region slightly larger than the bond area using alumina grit.
3
Apply AC-130 by brush, wipe, or dip. Keep surface wet for a minimum of 1 minute.
4
Drain and dry under ambient conditions for minimum 60 minutes.
5
Apply primer or adhesive within 24 hours. Keep surface clean during this window.
Available Kit Sizes
50 mL
Two-part kit
100 mL
Two-part kit
500 mL
Two-part kit
1 L
Two-part kit
Product 02 For Paint Adhesion
3M™ Surface Pre-Treatment AC-131
High-performance non-chromated sol-gel pre-treatment for aluminum, steel, and titanium alloys prior to painting with epoxy or polyurethane-based organic coatings. Qualified to multiple OEM specifications. Available in blue (BB) and clear (CB) versions.
Paint Adhesion Aluminum · Steel · Titanium Non-Chromated Blue (BB) or Clear (CB) Multiple OEM Specs
Description
AC-131 is a water-based, non-chromated sol-gel system that improves adhesion between metallic surfaces and epoxy or polyurethane-based organic coatings — meeting high-performance aircraft paint application requirements. It provides equivalent or better wet and dry adhesion performance vs. traditional conversion coatings in both OEM manufacturing and repair/repaint applications.

AC-131 is proven to significantly reduce rivet rash — the loss of paint at rivet heads on forward aircraft sections that occurs with inferior surface prep products. This protects against corrosion and maintains aircraft appearance over the service life. Available in blue (AC-131 BB) for visual verification of coverage, or clear (AC-131 CB) where no color indicator is needed. Applied by brush, dip, or spray, curing under ambient conditions.
Key Benefits
Equivalent or better wet and dry adhesion vs. traditional conversion coatings
Proven to significantly reduce rivet rash on forward aircraft sections
Non-chromated — reduces hazardous waste and associated handling costs
Significant water reduction during use vs. conventional processes
Total cost reduction compared to traditional conversion coating processes
Qualified to multiple customer specs across the aerospace industry
Available in blue (BB) for coverage confirmation or clear (CB) for invisible application
Technical Data
TypeWater-based non-chromated sol-gel
SubstratesAluminum, steel, titanium alloys
Compatible TopcoatsEpoxy & polyurethane-based coatings
ApplicationBrush, dip, or spray
CureAmbient temperature
Chromate-FreeYes — non-chromated
VersionsAC-131 BB (blue) / AC-131 CB (clear)
Primary Application
OEM Manufacturing — pre-paint surface prep on aluminum, steel, and titanium airframe components
Repair / Repaint — MRO and depot-level paint strip and repaint operations
Rivet Rash Prevention — forward aircraft sections where paint loss at rivet heads increases corrosion risk
Field Application — ambient cure allows AOG and on-wing applications without facility infrastructure
Version Selection
AC-131 BB · Blue
Blue color allows visual confirmation of complete surface coverage during application. Preferred for inspection-critical applications.
AC-131 CB · Clear
Clear version for applications where no color indicator is needed or where the treated surface must remain visually unchanged.
AC-130 vs AC-131 — Quick Reference
Property
AC-130
AC-131
Primary Use
Structural adhesive bonding
Paint / coating adhesion
Substrates
Al, steel, Ti, composites
Al, steel, Ti alloys
Compatible With
Epoxy adhesives & bond primers
Epoxy & polyurethane coatings
Format
Two-part kit
Single component (BB or CB)
Application Method
Brush, spray, dip, wipe
Brush, dip, spray
Cure
Ambient — 60 min min.
Ambient temperature

Why Source 3M™ Surface Prep Products for Bonding from Coast-Line?

Full Documentation

AS9120-certified distributor. Certificate of Conformance and specification compliance documentation available for every order.

Authorized 3M Distributor

Genuine 3M products with full lot traceability. Qualified to Boeing BMS and other OEM specifications, not gray-market product.

Application Support

Our team can help you select the right product and kit size for your process, including structural bonding, painting, and AOG field repair.

AOG Ready

Small kit sizes available for same-day dispatch. We understand AOG situations, so call us directly for urgent requirements.

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Source 3M™ Through Coast-Line.

Whether you need a single roll of film adhesive or a core splice, our team can supply the full 3M™ portfolio with fast turnaround and U.S.-based technical support.

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Product 03 For Structural Bonding
3M™ Scotch-Weld™ Structural Adhesive Film AF 163-2
High-performance thermosetting epoxy film adhesive for bonding metal and composite structures — the natural bonding step after AC-130 surface pre-treatment. Delivers high fracture toughness and peel strength across a broad temperature range, in solid-panel and honeycomb sandwich construction.
Film Adhesive Metal · Composite · Honeycomb Epoxy Thermoset -67°F to 250°F AF 163-2 · AF 191 Families
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
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.