Saturating the Grain: Why Polymerized Tung Oil is my favorite for Spalted Wood

When you're working with spalted wood, you're working with a collaboration between nature and the craftsman. Spalting—the colorful zoning caused by fungi during the decay process—creates some of the most dramatic patterns found in any species of wood. But as any turner knows, the real magic doesn't happen on the lathe; it happens during the finishing process.

The Challenge of Spalting

The high contrast of spalted maple or birch can easily be overwhelmed by the wrong finish. A heavy film finish, like a thick polyurethane or lacquer, can create a "plastic" look that sits on top of the wood, masking the organic depth and killing the tactile experience that makes handmade woodenware so special.

This vase was finished with four coats of polymerized tung oil and then buffed with carnuba wax.

Why Polymerized Tung Oil?

For my latest vase, I chose Polymerized Tung Oil (PTO). Unlike standard tung oil, which can take weeks to cure, polymerized oil is heat-treated to accelerate the drying process without sacrificing the finish's characteristics. Here is why it's my favorite for high-contrast pieces:

• Saturation: It sinks deep into the wood fibers, causing the creamy tones to warm up and the black spalted lines to "pop" with an intensity that surface finishes can't match.
• Tactile Feel: It preserves the natural feel of the wood. When you run your hand over the piece, you feel the grain, not a layer of plastic.
• Satin Glow: Instead of a harsh, reflective mirror shine, PTO provides a sophisticated satin glow that highlights the form and the figure of the wood equally.

The Process

Applying the finish is a meditative part of the craft. After sanding the piece to a high grit, the first coat of polymerized tung oil is applied. The transformation is instantaneous—the "wet-out" reveals the true character of the piece, turning a dry, matte surface into a vibrant work of art. You wipe off any excess after 10-15 minutes. After 24 hours, I lightly sand with 600 grit sandpaper and wipe off any excess with denatured alcohol. I apply another coat the same way, wiping off excess after 10-15 minutes. I usually do 3-4 coats to bring out the matte sheen that I love.