APF4-WHITE (1-USqt)

APF 4 Polyester Filler

Overview

APF 4 Polyester Filler is a premium-grade, low-shrink polyester repair filler designed for industrial, aerospace, tooling, and composite repair applications. Engineered for rapid curing, excellent adhesion, and superior finishing characteristics, APF 4 bonds to a wide variety of substrates while providing minimal shrinkage and outstanding machinability. Its fast-setting properties enable many repair operations to be completed in less than 20 minutes from application to finished repair.

Key Technical Characteristics

• Product Type: Polyester repair filler
• Resin System: Polyester resin with BPO cream hardener
• Mix Ratio by Weight: 100 parts filler to 2 parts hardener
• Appearance: Thixotropic paste
• Available Colors:
  • White
  • Gray
  • Brown
• Mixed Density: 1.63 g/cm�
• Pot Life (100 g at 25°C): 4-7 minutes
• Glass Transition Temperature (Tg): 53°C
• Peak Service Temperature: 141°C
• Hardness: Shore D 87-90

Core Performance Benefits

• Exceptional adhesion to a wide variety of substrates
• Very quick-setting formulation reduces repair time
• Minimal shrinkage during cure
• Excellent sanding, machining, and finishing characteristics
• Easy mixing and application
• Suitable for both structural and cosmetic repair operations
• Supports rapid turnaround in maintenance and production environments
• Produces smooth, high-quality finished surfaces

Typical Applications

• Composite component repair
• Aircraft interior and exterior cosmetic repairs
• Tooling modification and refurbishment
• Honeycomb panel repairs
• Fiberglass component repair
• Metal surface restoration
• Industrial maintenance operations
• Pattern making and model finishing

Material Engineering & Design Features

APF 4 is formulated as a high-performance polyester filler designed to provide excellent substrate adhesion while minimizing cure shrinkage. The thixotropic consistency allows easy placement and shaping without excessive sagging, making it suitable for vertical and contoured repair areas.

The material bonds effectively to numerous substrates including:

• Wood
• Aluminum
• Cast Iron
• Cast Steel
• Tool Steel
• Copper
• Bronze
• Fiberglass (FRP)
• Sheet Molding Compound (SMC)
• Honeycomb Panels
• Urethane Foam

Typical cured mechanical properties include:

• Tensile Strength: 14 MPa (2,100 psi)
• Flexural Strength: 41 MPa (6,000 psi)
• Compressive Strength: 43 MPa (6,200 psi)
• Hardness: Shore D 87-90

Installation & Handling

• Mix 100 parts filler with 2 parts hardener by weight
• Blend thoroughly for 1-1.5 minutes until uniform
• Scrape mixing surfaces during blending to ensure complete dispersion
• Clean, roughen, and dry repair surfaces before application
• Apply material while avoiding trapped air
• Allow filler to cure until tack-free before sanding or machining
• Finish and shape as required after curing
• Typical working time is 4-7 minutes at 25°C

Environmental & Compliance Notes

• Store in original unopened containers
• Recommended storage temperature: 15°C to 25°C
• Shelf Life: 12 months under recommended storage conditions
• Opened containers should be tightly resealed
• Ensure adequate workplace ventilation during use
• Wear appropriate gloves and eye protection
• Refer to the applicable Safety Data Sheet (SDS) before handling

Key Advantages

• Rapid repair capability with short cure times
• Excellent adhesion across multiple substrate types
• Minimal shrinkage improves dimensional stability
• Outstanding sanding and machining characteristics
• Suitable for composite, metal, and tooling repairs
• Available in multiple colors for repair flexibility
• High hardness and good mechanical strength after cure
• Reduces repair cycle times in maintenance and production environments