Sandpaper and Tung Oil

After initial assembly and a test spin, I took apart the Lendrum Saxony in preparation for finishing. I'm using tung oil, which along with linseed and a couple of other oils is known as a "drying oil". This means it will eventually harden into a durable, water-resistant finish.

Why tung oil? Well, I knew I wanted a more old-fashioned finishing compound that wasn't loaded with organic solvents, so that ruled out Watco and all the so-called wipe on "Danish oils" and polyurethane finishes. I also didn't want to darken the walnut, so that ruled out the linseed oil-based finishes. Finally, I wanted a matte rather than a glossy finish. Tung oil won in every category.

The Finishing Process

The wheel came to me reasonably well-sanded by Lendrum, but it needed a bit more work before I'd call it "finish sanded." On the rough spots I started with 180-grit wet/dry sandpaper followed by 320-grit sandpaper. Where the wood was fairly smooth I started with 320-grit. (I prefer the black wet/dry papers to the standard aluminum oxide papers commonly used by woodworkers. They last longer, and they bend more easily to fit the curves.) I then went over all the pieces again with maroon and grey non-woven abrasive pads. These wonderful scrubby pads are the same as 00 and 000 steel wool. I use them a lot in jewelrymaking and they're great—no steel wool filings to pick out of your fingers when you're done. Finally, I gave the flat parts an additional pass with 600-grit sandpaper. As is often the case on turnings, there were a few rough spots on the wheel spokes and the legs. I sanded these with successive passes of 180, 320, 400, and 600-grit sandpaper. Anything I couldn't smooth down I just left to be worked on later. Once the first coat of tung oil was dry, I'd be better able smooth the spot. After wiping the dust off all the pieces with a tack cloth, I was ready to apply the first coat of oil.

Tung oil straight out of the bottle is similar in consistency to maple syrup. To help the first coat penetrate into the wood, I thinned the oil about 1:1 with mineral spirits. Fortunately, the weather was nice and I could work outside. Using a small rag (and wearing latex gloves), I wiped on a coat of oil. The trick is to use the right amount: enough to look shiny, but not enough to drip. I let the oil penetrate for about 5 minutes then I wiped the surface dry. Tung oil doesn't dry by solvent evaporation in the traditional sense, but gradually polymerizes on contact with air. As this process begins to happen the surface gets sticky. It's important to wipe the residue off before the surface gets too sticky to wipe. After all the pieces were oiled and wiped, I waited a day or two for them to dry thoroughly. The difference between done and not done is amazing.

After everything had dried, I got out the sandpaper, scrubby pads, and steel wool and started again. I went over each surface with 600 grit sandpaper, the grey pad (000), and 0000 steel wool. The wood glowed. I paid particular attention to the rough spots and was able to to smooth down most of them.

At this point, the wood already looked so nice that I decided to apply only one more coat of oil. Tung oil may be applied many times, so I can always put another coat on at some point in the future. This time I used the oil right out of the bottle at 100%. I wiped on a very thin coat and rubbed it in with my hand (this is why it's called a hand-rubbed finish!) When most of the oil had absorbed and the surface was getting sticky, I wiped it dry and set it aside.

Fast-forward another day. I've started buffing each piece with 0000 steel wool. The finish is amazing: just a slight sheen and lots of depth. As soon as all the pieces are done I'll reassemble and start spinning.

My hands are sore from the endless sanding and I've been getting by on less sleep than usual this last week, but the end result will be worth the effort. This wheel is a lovely piece of functional art.