hardener

American  

[hahr-dn-er] / ˈhɑr dn ər /

noun

1. a person or thing that hardens.

2. a substance mixed with paint or other protective covering to make the finish harder or more durable.

3. Photography. a chemical used to raise the melting point of an emulsion.

---

ˈhardener British  

/ ˈhɑːdənə /

noun

1. a person or thing that hardens

2. a substance added to paint or varnish to increase durability

3. an ingredient of certain adhesives and synthetic resins that accelerates or promotes setting

---

Etymology

Origin of hardener

First recorded in 1605–15; harden + -er ¹

Example Sentences

Research specialist Alex Baer painted the greenhouse’s exterior with several coats of whitewash mixed with a hardener to block the sun’s rays and help the coating withstand winter rainstorms.

From Los Angeles Times

The hardener, sold separately, is $6.99 for a .37-ounce tube.

From Washington Post

Mix the resin and hardener and press the mixture into the screw holes with a putty knife.

From Washington Post

You’d have to mix its two thick components — a polyamide hardener and an epoxy resin — and then carefully try to get it into the crack without making a mess.

From Seattle Times

A kit with four ounces of resin and four ounces of hardener costs $17.99 at rockler.com.

From Washington Post