Finishing Sculpted Furniture
In his Santa Barbara, California, shop, Victor DiNovi makes the wood he works look as stunning as the one-of-a-kind furniture designs he's created for the last 30 years or so. That's not such an easy task, considering all the different wood species he employs.
"I use lots of American hard maple and black walnut, Honduras mahogany, imbuya and iroko from Africa, Hawaiian koa, East Indian rosewood, and teak," says Victor. "Because the majority of what I make is for certain people—and people normally have a preference for either light or dark woods—I use the wood that works best for the commission."
Preparing any wood for a finish always takes time, but it's especially true for penetrating (oil) finishes, according to Victor. "The key to success with a penetrating finish is preparation. In other words, it requires a lot of work.
"Take sanding," he continues. "You can build a beautiful piece of furniture that's very smooth to the touch. But when you apply the finish, little sanding scratches appear that detract from it. That's because when you sand, the abrasives not only cut, but abrade the wood. The finish then travels into the abrasions to make them visible, especially on light woods. So very often you have to sand on faith. That is, you know you've sanded enough but you sand some more anyway, realizing that some abrasions may show up."
To a professional woodworker, though, lots of sanding prior to finishing becomes a matter of economics. He says, "It takes too much time, especially because my furniture has few straight planes. So I use an auto-body grinder, power planes, and power chisels to get the wood to rough-sanded shape. Then I go over my pieces with a random-orbit sander down to 220-grit. I rarely sand any finer than that before my finish goes on." But as you'll find out, there's plenty of sanding to come.
Stages 1 & 2
"Basically, there are two types of finishes for furniture: penetrating oils, such as Danish oil, and film finishes, such as lacquer and varnish," Victor notes. "Oils give wood a rich glow. But they don't protect it. Film finishes protect, but do little for the wood's natural beauty."
Victor, though, discovered a two-stage finish a few years ago made by General Finishes (General Finishes Corp., P.O. Box 51567, New Berlin, WI 53151, 414/786-6050) that has some of the advantages of both types. "I call the finish a compromise because the first coat has the good look of oil, and the top coat—although not film—has body. So the finish not only has a deep luster, but it's relatively tough," he comments.
Called Sealacell, the first coat is a clear penetrating sealer of tung oil, the woodworker explains. "Like a Danish oil, it cures so slowly that essentially it doesn't cure. I apply this first coat, thinned about 25 percent with paint thinner, with 220-grit wet-dry paper and actually sand the piece with the grain, with the oil as a lubricant. Then I wipe it off clean and give it another sanding with the finish. After wiping that off, I let the oil dry, then go directly to the top coats."
For Victor's second stage, the top coat, he wipes on Arm-R-Seal, also made by General Finishes. "It's an oil-and-urethane mixture that gives the wood a satin finish," he says.
Between top-coat applications, put on with a cloth, Victor rubs down the surface with 0000 steel wool. "There's no easy way to get around this aspect if you want a beautiful finish," he notes. "I put on six, seven, even eight finish coats, all rubbed after application. This finish is almost like applying a hand cream. You strengthen the wood fiber from the inside out as opposed to putting a film over the top." Once he's applied the finish, he lets it dry for eight hours.
The California woodworker admits not following to the letter the manufacturer's label instructions on application. "Many people don't even bother to read the directions on the label. When I find a new finish, I do because they're a place to start," says Victor. "For instance, if the directions say 'apply two coats' assume that you'll need more. Those are just the words of some copywriter wanting to make it seem easy. And two coats will give you some success. But as you can see, I've developed an intensive application process-for a reason."
Victor's reasoning tells him that the burnishing he does with steel wool on the top coats makes the wood ultra smooth because it has a quite different cutting action. "Sandpaper cuts and digs, opening up the wood fibers. Steel wool rubs them closed. I'm literally compressing the surface. And the number of coats I put on depends on the porosity of the wood species I'm using. Some woods fill up with finish faster."