Woodworker's Journal 2011-35-Winter, страница 53
Watco", the granddaddy of Danish oil finishes, is more durable than oil or wax, but just as easy to apply. Oil Advantages When I was young, we would put a spot of oil on brown bag paper, then hold it up to the light. The oiled section let more light in, making the paper translucent. Paper is made from trees, so it is no surprise that oil will do the same thing to wood. In fact, one of oil's strongest advantages is that it penetrates into wood, curing in and among the surface fibers. This is because oil is made of molecules small enough to seep down into the wood rather than merely sit on top. As a result, oil makes wood look richer and more translucent without adding a film on the surface. There are two decidedly different types of oils that woodworkers use: drying and non-drying oils. Drying oils will change from liquid to a solid film when exposed to oxygen in the air. Nut oils Ginseed, tung, etc.) are drying oils, but vegetable (peanut, olive) and mineral oils are non-drying. Edible mineral oil is popular on food contact items, like cutting boards. However, non-drying oils stay wet indefinitely, and will wash off when the board is scrubbed with soap and water. Because they do not dry to a solid film, non-drying oils are considered a wood treatment, but not a finish. The most common and least expensive of the drying oils is linseed oil. It will dry by itself, but it does so slowly. To speed things up, formulators add heavy metal salt "driers" to raw linseed oil, which causes it to cure faster. The result is called "boiled linseed oil," in spite of the fact that it is never boiled. Tung oil dries a little bit faster than linseed oil on its own, but it too is sometimes modified to cure more quickly. The best method I have found for applying oil is to flood it onto the wood, adding extra to keep the surface wet in areas where the oil is quickly absorbed. After 10 minutes, wipe off everything that has not been absorbed. Don't add solvent. For a smoother, richer finish, repeat the process, this time sanding the oily wood with fine wet-and-dry sandpaper. This will create a slurry of oil and wood dust, filling tiny pores and leaving the surface even smoother. Danish Oil What goes on as easily as oil and also makes wood look terrific, but dries quicker and is more durable? Danish oil, often lumped in as an oil finish, is actually a thin 011 and varnish mixture. The oil helps bring out wood's beauty, while the varnish resin offers somewhat more protection against chemicals, heat, scratches and stains than either oil or wax. Typical of this group is Watco®, both the oldest and best-selling. Many woodworkers create their very first finish using Watco, and return to it frequently. It comes in a variety of colors as well as natural (clear). The directions on the can are excellent: apply it liberally to the wood, let it soak in for 15 minutes, reapply, then wipe off the surface. Use Watco either as a one-coat penetrating finish, or to add as many subsequent coats as you like. Applied no more than one coat per day, you can build up a finish as thick, beautiful, and durable as varnish, with no brushes to clean or brush marks to rub out. The good news is that a multi-coat Watco finish is durable enough for most anything you make, even kitchen cabinets or a dining room table. & __X You can create a classic limed oak look by applying white paste wax and wiping it off, leaving extra in the corners and recesses. Above, a brown wax darkens wood. WINTER 2011 53 |
