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409 Microsphere Blend

Fairing Filler

A pure white, hollow glass bubble based, low density filler designed for filling and fairing of fibreglass. When the filler is mixed with WEST SYSTEM epoxy at a ratio of 10% to 25% by weight, it creates a smooth creamy paste for filling and fairing over glass fibre repairs. The cured epoxy/filler is very easy to sand. Being white in colour the cured epoxy filler mix will be hidden easily behind paint or polyester gelcoat but must be protected by further coats of epoxy if used below the waterline.

Designed for:

  • Wood Bonding
  • Adhesion
  • Gap Filling
  • Penetrating Wood Fibres
WEST SYSTEM| image: 409 Filler


Thicken epoxy blended resin/hardener and create a multi-purpose adhesive for:

  • Large Scale Fairing
  • Fibreglass Repairs
  • Architectural Repairs
  • Autobody Repairs
  • Marine Bottom Repairs


  • Colour | White
  • Cures to white
  • Hollow glass bubble-based


  • 409-1 | 100g Microsphere Blend
  • 409-2 | 400g Microsphere Blend
  • 409-4 | 3kg Microsphere Blend

Filler Facts


Modifying with fillers and additives makes WEST SYSTEM epoxy extremely versatile for a wide variety of bonding and coating applications. Epoxy can be thickened to the ideal consistency needed for a particular job. Epoxy thickened with adhesive (high-density) fillers strengthens structural bonds, bridges gaps, and fills voids. Epoxy thickened with fairing (low-density) fillers is easily sanded and shaped after it cures.

Bonding with Fillets

Epoxy fillets can make a bond between components even stronger than the components themselves, ensuring that loads can be transferred between structures and panels effectively, with no risk of stress fractures or other structural issues.

Using WEST SYSTEMFillers & Additives