Iron out a dent in wood

By the end of this blog post, I will make this "cat face" or "schilling" — as some old time carpenters call the hammer head dent left on a wood surface when you miss striking a nail— disappear. Please note the small knot above the dent so you don't think I simply photographed another portion of the board. This is no huckster, slight of hand trick. This is science.

When wood is dented, the cell walls of the wood fibers become crushed and deformed. By mimicking the same process that causes doors and drawers to swell and stick in the humid summer, one can coax the deflated cell walls of the wood surface to rise again.

First, I saturate the mar with water.

In some cases, depending on the softness of the wood, as the water soaks into the wood like a sponge you can actually see the wood begin to swell and the hard lines of the dent begin to soften.

When the big bead of water disappears after, about 15 minutes or so, I add more water until it no longer beads and instead begins to travel to the surrounding dry surface. The damaged area has soaked up as much water as it will hold.

I then cover the circular dent with the smooth side of a bottle cap and rest a pre-heated iron set to high on top.

This focuses heat directly on the hammer head damage causing all the water inside to evaporate.  Molecules begin moving around rapidly, steam begins to build and the wood cells begin to expand till...

Boom! The wood pops back in place and it's good as new.

You may need to repeat the process a few times, and after the first round, it helps to rest the iron directly on the board. A few passes of some 220 sandpaper even makes it better smoothing out any of the torn fibers and resulting raised grain.

If you are repairing a ding in a finished piece of furniture, you may need to lightly perforate the damaged area with a needle in order for the water to soak in past the sealer. To protect the rest of the finish from the heat and water, use the bottle cap on top of a dry rag.