Flexible Yet Strong: When to Specify 3M Urethane Adhesives EC-3532 and EC-3587
Continuing our series on 3M Scotch-Brite epoxies, this article covers 3M EC-3532 and EC-3587 urethane adhesives and how they are commonly used in aviation and aerospace manufacturing and repair.
Epoxies do dominate structural repair adhesive uses, but urethane adhesives fill a critical niche where flexibility, impact resistance, and gap-filling capability are required without sacrificing structural performance. Structural repair teams deal with maintenance issues that involve damage from vibration, thermal cycling, and dissimilar material interfaces, and 3M EC-3532 and EC-3587 are urethane adhesives designed to address these issues.
Greenwood Aerospace carries a large catalog of 3M products and is your go-to for epoxies, sealants, and abrasive materials. You can source these two items right now!
62331655407 / 021200-84992
FILLER: VOID, B/A, B-1/4, GRAY, 3M EC3587, AEROSPACE, PINT KIT
KT
021200-65219
ADHESIVE, URETHANE, B/A, EC3532, QUART KIT
KT
Introduction to Urethane Adhesives
Urethane adhesives are flexible polymers that cure when mixed in appropriate ratios: an isocyanate and a polyol resin. The chemistry between these two chemicals produces a polyurethane network that provides strength and elasticity. Bonded assemblies can then absorb shock and vibration rather than transferring stress directly to the substrate. It really is a brilliant system, with the adhesive acting as a shock absorber while providing great adhesion.
3M Scotch-Weld urethane adhesives cure at room temperature or with heat, resulting in a tough, impact-resistant bond.
Key Characteristics and Benefits
3M Scotch-Weld urethane adhesive EC products bond strongly to metal, plastic substrates, composites and many primed or painted surfaces when working with coated aircraft components.
Both EC-3532 and EC-3587 are two-part urethane systems that form tough, impact-resistant bonds for mixed material assemblies. EC-3532 has a 5-15 minute work life, and EC-3587 has multiple class options with extended work times depending on formulation, so you have flexibility in your assembly planning.
A big handling advantage is their non-sag behavior. EC-3532 becomes non-sag 30 seconds after mixing, and EC-3587 offers excellent flow control, so both products are great for vertical or overhead applications where adhesive migration is unacceptable.
Full cure is at room temperature, typically 24 hours, and can be accelerated with controlled heat. Once cured, these adhesives deliver consistent bond strength and the elasticity to resist cracking and debonding under load.
Applications and Uses of Scotch Weld EC
3M Scotch-Weld urethane adhesives are a common joining material in aircraft manufacturing and repair, especially in applications where rigid structural adhesives can transmit stresses through substrates. They are an impact-resistant material that also offers sag resistance and strong adhesion.
EC-3587 is used as a structural adhesive, void filler, or fairing compound. Its sandable cured state allows technicians to shape and contour bonded areas, great for aerodynamic fairings, surface smoothing, and cosmetic finishing before coating or painting.
The gray cured appearance of EC-3587 provides visual contrast during sanding and inspection. EC-3532 is great for structural bonding to primed or painted substrates, where impact resistance and environmental durability are required, and prep work is already done.
Outside of aerospace, these adhesives are also used in automotive, industrial fabrication, and construction, where reliable bonding and gap filling are required. Available in tube kits and cartridge systems for small batch repairs and larger production runs, with flexibility and handling strength.
Specification and Selection of 3M Scotch-Weld
When specifying 3M Scotch Weld urethane adhesives, consider the required bond strength, flexibility, and hardness, as well as the substrate materials and environmental conditions. These adhesives offer fast results, with a fast-acting formula that cures at room temperature or with heat, making them suitable for applications where speed and efficiency are crucial.
EC-3532 is well-suited for applications that require high handling strength and strong adhesion to coated surfaces, whereas EC-3587 is better suited for applications where gap filling, sanding, and surface fairing are part of the repair process.
Both adhesives offer room-temperature curing with the option of heat acceleration, allowing workflow times to be increased for production, inspection, and repair.
3M Scotch-Weld Urethane Adhesives: EC-3532 vs EC-3587 Comparison Table
Make sure to review the technical data sheets for each of these products from 3M, available below:
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Final Thoughts on Urethane Adhesives from 3M
While both are urethane adhesives, their practical characteristics differ considerably. They serve different purposes and have a place in your structural repair and maintenance toolkit, so to speak.
You can buy these products from the links below:
62331655407 / 021200-84992
FILLER: VOID, B/A, B-1/4, GRAY, 3M EC3587, AEROSPACE, PINT KIT
KT
021200-65219
ADHESIVE, URETHANE, B/A, EC3532, QUART KIT
KT
Greenwood Aerospace is proud to partner with 3M to provide products to our warfighters and federal partners, and our GSA Advantage catalog of items makes the process smoother, faster, and easier for you!
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