Evidence grade: A1 — First-hand testing (TDS/spec sheets, ASTM/ISO, lab tests)
Answer: They don't disagree — they measure different things. Pot life is the usable time of a standard 100 g mass in the mixing cup (the worst case, where trapped heat accelerates the cure); working time is the usable time as a thin film on the part (longer, because heat escapes); cure time is a ladder of milestones — solid, then handling strength, then full strength over days [1][2].
Effort: N/A — debunk/reference, no procedure
The three terms, untangled
Pot life — how long a stated mass (usually 100 g at 25°C) stays liquid enough to use, sitting in the pot. West System's sheet: 12 minutes for 105/205, 21.5 for 105/206, 26.5 for 105/207, 51 for 105/209 [1]. This is deliberately the pessimistic number: a cup of mixed epoxy traps its own reaction heat, and heat accelerates the cure (see Repair Lab B8).
Working time — how long you can actually position, clamp, and adjust the parts. Six10's TDS lists "working time, thin film" at 42 minutes — same number as its 100 g pot life in that product, but the asterisk matters: "*Epoxy cures faster at higher temperatures and in thicker applications" [2]. Spread thin on a joint, heat escapes into the parts and the air, so the reaction runs slower than in the cup. For most products, your real working window on the part is longer than the pot-life number suggests — but only if you get the mixed epoxy out of the cup promptly.
Cure time — not one moment but a ladder: - Cure to a solid (thin film): hours — 5–6 h for Six10 [2]; 5–7 h for 105/205, up to 20–24 h for 105/209 [1]. - Cure to working strength: days — 5–7 days for Six10 [2]. - Cure to max strength: 5–9 days depending on hardener [1].
"Hard to the touch" is the bottom rung of that ladder, not the top. Loading a joint at "solid" instead of "working strength" is one of the most common ways a good repair fails early.
Why the numbers look contradictory
Two manufacturers can publish different numbers for similar epoxies and both be right, because the test conditions differ: mass (a 100 g pot vs. a thin film), temperature (cure roughly doubles in speed every ~10°C — exact factor varies by formulation, unverified as a universal constant), and which rung of the ladder they're naming. When a sheet says only "cure time: 24 hours" with no qualifier, you don't know which rung — that ambiguity is the entire confusion this article exists to end.
Honest limits
- All cited times are at stated reference conditions (25°C, stated mass/film). Your shop temperature and your batch size move every number — hotter and bigger is faster, colder and thinner is slower.
- "Working time" on the datasheet assumes the epoxy leaves the cup. Epoxy left sitting in a mixing cup follows the pot-life clock, and the exotherm can run away (Repair Lab B8).
- These are adhesive-industry conventions. "Set time" on a consumer label and "tack-free time" on a coating sheet are related but distinct terms — don't swap them in.
Sources
- West System — Typical Physical Properties of West System Epoxy (Wessex Resins, Version B 08/08). Pot life (100 g @ 25°C): 12 / 21.5 / 26.5 / 51 min (105 with 205/206/207/209); cure to solid state: 5–7 / 9–12 / 9–12 / 20–24 h; cure to max strength: 5–9 days. URL: https://www.ecfibreglasssupplies.co.uk/user/TechnicalDataSheet/618.pdf
- West System — Six10 Thickened Epoxy Adhesive TDS (Rev. 3). Pot life (100 g at 25°C) 42 min; working time (thin film) 42 min; cure to a solid (thin film) 5–6 h; cure to working strength 5–7 days; "*Epoxy cures faster at higher temperatures and in thicker applications." URL: https://eu.westsystem.com/app/uploads/2023/07/Six10Thickened-Epoxy-Adhesive-Rev-3.pdf
A 30 / 3–4 / 24 ladder (@77°F: working time ≤30 min, initial cure 3–4 h, full load ≥24 h) maps to exactly this ladder — working time, cure-to-solid, cure-to-working-strength.
Repair Lab · Release 1 · Evidence last checked September 30, 2026 · A project of AOJEL