MAKE:TNT Tools 'n' Tips

Minwax High Performance Wood Hardener

by Stefan Jones

As seen in MAKE 02 Toolbox


Tool photo.

This is as much an invitation to experiment as
a review.


Minwax Wood Hardener is an obnoxious-smelling, toxic, flammable, watery-thin fluid used to treat weathered or rotten window frames and door sills. It's essentially a deep-penetrating liquid plastic. It binds together wood fibers, replacing the natural lignin "glue."


It works as advertised, but I, and others in the rocket-nerd community, have found some additional applications. When applied to fresh, new wood, it creates a hard, dent-resistant,
water-resistant surface that (when thoroughly dry) sands very nicely. It also seals the wood grain, meaning you'll need less paint or stain when finishing porous wood.


Cardboard and cardstock soaked in the stuff become hard, rigid, and water resistant; the
resulting material resembles phenolic plastic and can be sanded and machined with power tools.


Some hints: Never work with this stuff indoors! The solvent in Minwax Wood Hardener is vile stuff. Use a disposable brush, containers you don't mind throwing away, and wash your hands afterwards.


Porous woods expand a bit with Wood Hardener. Treating only one side of a piece of wood may cause it to warp.


Initial sanding of treated pieces may be difficult because Minwax strengthens the wood's surface "fuzz." After an initial smoothing, however, you'll have a surface that can be wet-sanded to a high polish.

In home improvement stores and on amazon.