Eleven Grooved Box Step by Step – Part 10: Apply Danish Oil Finish
Apply a Danish Oil Finish
View the original Woodwright’s Shop video here.
Roy leaves his Oak box unfinished, or suggests it be covered with veneer. That would be interesting, but I like a classic rubbed Danish oil finish. This always starts with a very heavy first coat. Completely flood the piece, let it sit for 1-3 hours then wipe off any excess. Let it cure for a day, or two days in cool weather, before applying another coat.
liquid oil enters and caps pores in the wood, trapping air below, so it’s best to apply at the warmest time of day, usually 3:00-4:00 PM. Then when the piece cools down, oil will be drawn farther into the wood by the trapped air contracting (good). If instead you apply oil early in the day and let the piece warm up, the trapped air will expand, the oil “bleeds” out the pores (bad), and you have to wipe it down several times.
It’s always satisfying to watch the grain come out when applying the first coat of oil.
After a couple of hours the oil saturated wood is wiped down with paper shop towels. Any wet areas must be removed. I wrap a paper towel around the end of a plastic putty knife to get into corners.
I once asked my Danish brother in law how to apply Danish Oil. He replied “Once a day for a week, once a week for a month, once a month for a year, once a year forever.” A mantra good for Scandinavians, but I use an ancient secret technique (that I got off the internet) to shortcut the process. I apply the oil with wet or dry sandpaper, starting with 320 grit on the second coat, 400 grit for the third, and 600 grit for the fourth coat. That’s usually enough for a finish so smooth that it begs to be touched. I cut a full sheet of sandpaper into 16 pieces and use a small wood block to do the application. It is critical to keep the work area clean. One particle of sawdust on the applicator will destroy the hard won finish.
Below I’m finishing up the second coat application. I wet the surface with Watco, then sand lightly a few minutes until it begins to set up. You can tell by the sandpaper starting to drag noticeably. At that point I ease off pressure on the sanding block and lightly go over the surface while holding the piece up to the light so I can see how even it is. The slurry of oil and sawdust will be pushed into and fill the wood pores. The process is not unlike spit shining your shoes.
I’ll only apply two coats to the interior of the box and don’t bother sanding in there too much.
In 1-3 hours, the sanded surface will have dried to a dull haze. I wipe the piece down to remove any excess oil, and all dried haze from the surface. At this stage, wipe the surface cross grain to avoid pulling the drying slurry from the wood pores. Rub until all the hazy coating is removed. I check carefully in strong reflected light as the haze is very difficult to remove after it has completely dried. 12-24 hours later wipe the piece again, using more pressure. The oil will still be a little plastic and the surface smooths out even more.
Rubbing the surface out smoothly is critical to the success of the finish. The piece will fingerprint easily at this point, so I always hold it with a paper towel.
I wait at least a day between coats, repeating the sand and wipe procedure with successively finer wet/dry sandpaper. Finally, allow two days for complete drying, then apply two coats of paste wax.
I’ve used the same sandpaper procedure with Boiled Linseed Oil, thinning the first flood coat a bit with turpentine. It comes out just as smooth but the Watco cures faster.
These four boxes were made between late July and late October 2013. There were several other distracting projects in August and September that lengthened the build. I can make a box in two days if I have the jigs set up, but my goal is to get practiced enough to make one in a single day.
Finally, the results of a couple months work, ready for Christmas wrapping.
Update July 2014:
Somebody at the local woodworkers club left two slabs of Butternut on the free table. I turned them into pencil boxes. Attempted to stain one with Minwax Chestnut, it did not come out so good. The other box I left alone and finished with the usual Watco natural. My spit shine technique takes longer but I can get a really amazing surface in four coats.
Splines and lip strip fit very well. Reflected light on the box side shows how well the oil has filled in wood pores. Compare the inside of the box which did not get the super smooth treatment.