Cure, post cure, and why a day is not done
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Three stages, not one
Gel, where it stops flowing. Hard, where it demolds. And full cure, where the reaction is as complete as it will get and the mechanical and chemical properties reach their final values. Most products quote all three and most makers only watch the second.
Why it matters commercially
Strength, hardness, chemical resistance and how it takes a polish all improve through full cure. Sanding and finishing too early gives a worse result and gums the abrasive, and shipping too early means a piece finishing its cure in transit.
And why it matters for exposure
An incompletely cured surface still has reactive material at it. Handling a piece that is hard but not cured, without gloves, because it looks finished, is a real and routine exposure that people do not count.
Post cure with heat, where the product allows
Gentle warmth drives the reaction further toward completion and some products specify a schedule for it. It is a real step with real benefits and it has to follow the manufacturer’s numbers rather than an improvised session next to a heater.
Cold is the common cause of a cure that never finishes
Below a product’s minimum temperature the reaction slows and can stall short of completion, leaving a piece that is soft or tacky and will stay that way. A cold workshop in winter is the usual culprit and a warm cure space is the usual fix.
Build it into the schedule
If full cure takes several days, that is lead time, not a delay. Quoting a turnaround that assumes demolding is finishing is how a maker ends up shipping pieces that are still reacting.
Keep it covered while it cures
Dust landing on a tacky surface is in the piece permanently, and a workshop that has been sanded in is full of it. A box over the casting costs nothing and saves the finishing work that would otherwise be needed to remove it.