3M Scotch-Weld Structural Void Filling Compound EC-3505 B/A FR, 400 mL Cartridge

$ 114.25

  • Saves weight with the lightest pumpable/extrudable FR (Fire Retardant) void filler in the industry
  • Reduces labor cost and time with Pumpable/extrudable and non-sag compound that requires no hand-mixing
  • Cuts cycle time, as its sandable and machinable within 6 hours at 75°F after mixing
  • Stores, applies, and cures at room temperature for easy handling and reduced inventory costs

SKU: B1915N011

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3M Scotch-Weld Structural Void Filling Compound EC-3505 B/A FR is a two-part, low-density, flame-retardant epoxy compound that is stored, applied and cured at room temperature for significant savings in handling and inventory costs. Its extrudable, pumpable and non-sag performance helps aircraft manufacturers eliminate steps through reduced touch and cycle times.

We formulated 3M Scotch-Weld Structural Void Filling Compound EC-3505 B/A FR to be non-sagging and non-brittle. This helps make it an ideal solution for void-filling, edge-sealing/close-out, corner reinforcement, local reinforcement for mechanical fixation and complex gap-filling in honeycomb sandwich structures. EC-3505 B/A FR starts as a high viscosity, thixotropic paste for easy, controlled dispensing that won’t drip, sag or migrate. The mix ratio is 2:1 and provides a 60 minute work life to allow plenty of time to adjust fit prior to setting. EC-3505 B/A FR provides a four hour time window to reach handling strength and becomes fully cured in 48 hours at room temperature.

To help meet stringent standards for aerospace manufacture and maintenance flammability requirements (FR), the cured materials are designed to meet key industry fire retardancy regulations. Scotch-Weld EC-3505 B/A FR Compound is available in dual-chamber cartridges and bulk kits for use with pneumatic dispensers and bulk pumping equipment to meet needs small and large.

Adhesive Type



Edge and Void Filling, Edge Finishing




Aircraft Maintenance & Production Efficiency

Chemical Base



Light Brown

Compressive Strength

15 MPa (2200 psi)

Cure Rate

48 Hours

Cure Temperature

Room Temperature


0.44 g/cc

Flame Retardant


Meets Specifications

14 CFR-25.853(a)(d)

Product Form

Cartridge, Kit(set)

Storage Environment

Refrigeration Storage

Time to Handling Strength

4 Hours


60 minutes @ Room Temperature

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