Design Nomenclature / Physical Model Making
Resin
Also called casting resin, urethane resin, photopolymer, polyester resin
This entry has not been translated yet and is shown in English.
A dangerously ambiguous word. It names polyurethane casting resin, polyester laminating resin, epoxy, and photopolymer for SLA printers — four chemistries with different cure mechanisms, shrinkage, pot lives and hazards, sharing only that they arrive liquid. Nothing about the family predicts whether a resin is rigid, castable, paintable or safe to touch.
In practice
Ask which resin, then the shore hardness and the pot life. "Food safe" and "skin safe" are certifications held by a specific product — never properties of a family.
Not to be confused with
- RTV siliconeTwo-part rubber that cures at room temperature into a flexible mould. Tin-cure is cheap and forgiving, shrinks slightly, and slowly dies on the shelf. Platinum-cure is dimensionally stable and inhibits — sulphur clay, latex gloves and some tapes leave it permanently tacky, with no warning, no smell, and no fix but starting over.
- EpoxyA resin and a hardener that co-react rather than dry, so it cures inside a gap and will fill one. Strong on nearly everything, slow, and unforgiving of mix ratio — off-ratio epoxy stays soft forever and cannot be rescued, only removed. Nothing else bonds dissimilar materials as reliably.