Woodworker's Journal summer-2009, страница 18
niques to identify wood, but do make a point of stating that they — and you — are likely to only be able to nail down a wood's genus (for example, "some sort of oak") rather than necessarily a specific, exact species. The U.S. Forest Products Laboratory will identify a maxium of five wood samples per calendar year for a U.S. citizen. You can check out further details, like their requirements for the samples, at http://www2.fpl.fs.fed. us/ WoodlD/idfact. html. Joanna Werch Takes Ql've been finishing wood for 30 years, but I never have any luck with polyurethane, I get bubbles or bumps every time. Can you help me figure out how to get a smooth finish without spending hours and hours sanding and rubbing? Mark Armstrong Sacramento, California A You are not the only one facing this dilemma, but the manufacturers are listening to you. Rockier Polyurethane Gel (rockler.com) is designed as a foolproof wipe-on/wipe-off finish: it will give you exactly what you are seeking — a flawless polyurethane finish with no dust, bubbles or brush marks, and very little work. All you need to do is apply it correctly. Don a pair of vinyl gloves (it's not harmful, but it will make your hands sticky), and grab a piece of fine, gray Scotchbrite. Dip the Scotchbrite into the gel, and use it to scrub the finish onto the wood. Go back with a cloth or paper shop towels and wipe it all off. Wiping off the finish will leave a very thin, but uniform, coat, free of brush or rag marks. Apply one coat per day in exactly the same way. Three coats are a bare minimum; six or more are better. There's no need to sand between coats for adhesion, as long as you apply the next coat within two weeks. Sand only if you need to remove dust nibs, an unlikely scenario with a wipe-off finish. Michael Dresdner QOver the years, I've seen the following screw sizes: 2, 3, 4, 5, 6, 8, 10 and 12. What happened to sizes 7, 9 and 11? Skip Tenney Morgantown, West Virginia A Screw sizes — or more, accurately, screw gauges — are based on a numbering system that standardizes the thickness of the screw shank (not the threads) at its widest diameter. These numbers were established almost 60 years ago by the International Organization for Standardization (ISO). For instance, if a screw manufacturer follows ISO standards closely, a #4 screw will have a shank diameter of .112", and a #8 will have a .164"-thick shank. Manufacturers engineer screws within tolerances that may vary a few thousandths of an inch from ISO standards. As you know from buying screws, the higher the gauge, the thicker the shank. The gauges you've seen are those stocked most often in stores, but specifications for the more obscure #7, #9 and #11 — as well as #0 and #1 — do exist. They just aren't commonly manufactured or sold. LiLi Jackson summer 2009 21 |
