Filler Guides
WEST SYSTEM Epoxy fillers are used to thicken the basic epoxy resin/hardener mixture for specific applications. Each epoxy filler possesses a unique set of physical characteristics, but they can generally be categorized as either Adhesive (high-density) for bonding applications or Fairing (low-density) for sanding and fairing applications. Adding these filling agents to blended epoxy resin and hardener allows you to control the consistency of the epoxy. This lets you bridge gaps in joints, create either strong or sandable fillets with epoxy, or alter the cured density of epoxy, making it easier to sand smooth.
The first guide will help you determine the best filler for your application. The second guide tells how much epoxy a container will thicken to the listed consistencies.
Filler Selection Guide
The first guide will help you determine the best filler for your application. The second guide tells how much epoxy a container will thicken to the listed consistencies.
Filler Selection Guide
Filler Suitability: * * * * = Excellent, * * *=Very Good, * *=Good, *=Fair, (no stars)=Not Recommended
| Uses & Characteristics with epoxy resin/hardener mixture |  | |  |  |  |  |  |  |
| Adhesive Fillers ⇐ Highest Density/Highest Strength | Fairing Fillers Lowest Density/Easiest Sanding ⇒ | |||||||
| Small GRP repairs (Peanut Butter Consistency) | **** | |||||||
| Bonding Hardware with Epoxy—Increase load capacity—Maximum strength | **** | *** | *** | ** | ||||
| General Bonding (Mayonnaise Consistency) - Join parts with epoxy thickened to create a structural gap filler - strength/gap filling | *** | *** | *** | ** | * | |||
| Bonding with Fillets (Peanut Butter Consistency) - Increase joint bonding area and create a structural brace between parts - smoothness/ strength | ** | **** | ** | *** | *** | |||
| Laminating with Epoxy—Bond layers—Gap-filling, strong | ** | *** | **** | ** | ** | |||
| Fairing with Epoxy—Fills voids—Easily sanded—Gap filling | *** | **** | **** | |||||
Filler Buying Guide
| Epoxy Filler | Package Size | Package Weight | Epoxy Thickened to Ketchup Consistency | Epoxy Thickened to Mayonnaise Consistency | Epoxy Thickened to Peanut Butter Consistency |
| 402-1 402-2 | 150g 1kg | N/A | N/A | 25-30% |
| 403-1403-2 403-3 403-4 | 160g 800g 3.5kg 20kg | 4% | 7% | 16% |
| 404-1 404-2 404-4 | 250g 1.75kg 10kg | 35% | 45% | 60% |
| 405-1 405-2 405-4 | 150g 700g 5kg | 15% | 20% | 25% |
 | 406-1 406-2 406-3 406-4 | 60g 275g 1.5kg 10kg | 3% | 5% | 8% |
| 407-1 407-2 407-3 407-4 | 150g 700g 3.5kg 15kg | 20% | 30% | 35-40% |
| 409-1 409-2 409-4 | 100g 400g 3kg | 11% | 16% | 25-30% |
| 410-1410-2410-4 | 50g 200g 1.5kg | 7% | 13% | 16% |
| General Characteristics | Filler | |||||||
|---|---|---|---|---|---|---|---|---|
| 402 | 403 | 404 | 405 | 406 | 407 | 409 | 410 | |
| Mixing (Easiest = 5) | 3 | 5 | 2 | 4 | 3 | 2 | 2 | 4 |
| Texture (Smoothest = 5) | 1 | 1 | 2 | 3 | 5 | 4 | 4 | 4 |
| Strength (Strongest = 5) | 4 | 4 | 5 | 4 | 4 | 2 | 2 | 1 |
| Weight (Lightest = 5) | 2 | 3 | 1 | 3 | 3 | 4 | 4 | 5 |
| Sanding (Easiest = 5) | 2 | 2 | 1 | 2 | 2 | 4 | 4 | 5 |