Resin is a tough, sticky substance. In its natural form, resin is secreted by conifers (pine, spruce, larch) at points where the bark is damaged; it seals the wound and protects the tree. In construction and industry, ‘resin’ also refers to a large group of natural and synthetic resins used as binders.
Resin in wood
- Resin pockets and galls — local build-ups in softwood that can ‘bleed through’ when sawing or painting
- Sweating out — in heat, resin can seep out of knots; that is why knots are often first sealed with a knotting primer before painting
Synthetic resins in construction
Many modern building materials are resin-based:
- Epoxy resin — a strong glue and the basis for resin floors and coatings
- Polyester resin — for composites (fibreglass) and repairs
- Polyurethane resin — for adhesives, foams and injections
- Synthetic resin in paint and varnish — as a binder that forms a tough, protective film after curing
Points to watch
- Mixing ratio — two-component resins (resin + hardener) must be dosed accurately, otherwise they will not cure properly
- Working time — after mixing there is a limited ‘pot life’
- Ventilation and skin — many resins are irritant; work with gloves and good ventilation
Related terms
- Wood
- Glue
- Epoxy adhesive
- Polyester
- Primer
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