West System West System 105 Epoxy Resin — Mix Ratio & Calculator
Data sourced from manufacturer SDS & TDS · Last verified September 01, 2026
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Quick Answer
West System West System 105 Epoxy Resin mix ratio: 5:1 by volume, 5:0.86 by weight
Max pour depth: 0.125" · Full cure: 24h · Ideal temp: 72°F · Price: $70–$140/gal
⚠️ Exothermic Risk — The weight ratio (5:0.86) is NOT 1:1. Resin and hardener have different densities. Using a 1:1 scale ratio will result in incorrect curing. Always mix by weight using the ratio above.
Professional marine-grade epoxy for boat building, structural repairs, and woodworking. Used with 205 or 206 hardener depending on temperature.
| Volume Mix Ratio (A:B) | 5:1 |
| Weight Mix Ratio (A:B) | 5:0.86 — use this for scale mixing |
| Max Pour Depth | 0.125" / 3mm |
| Ideal Temperature | 72°F |
| Full Cure Time | 24 hours |
| Viscosity | 1000 cps |
| Coverage | 12 sq ft/gal |
| Average Price | $70–$140/gal (Marine & Structural market avg, 2026) |
Safety Note
The weight ratio (5:0.86) is NOT 1:1. Resin and hardener have different densities. Using a 1:1 scale ratio will result in incorrect curing. Always mix by weight using the ratio above.
The weight ratio (5:0.86) is NOT 1:1. Resin and hardener have different densities. Using a 1:1 scale ratio will result in incorrect curing. Always mix by weight using the ratio above.