Presented by Popular Woodworking Wood Prep Basics The Hows & Whys of Preparing Lumber Understanding Grain Direction PLUS: • Wood Preparation • Rules for Sanding Wood • Taming Handplane Tear-out • Why Wood Warps • Wood Selection Coarse, Medium & Fine @@[Q) Prep Thou shalt make it easier on thyself The second in our series on finishing shows you the best way to handle an unpleasant (but essential) job. HEN DOES THE finishing process begin? After the Wproject is fully assembled? Wrong. When you pre­ sand the parts before assembly? Wrong again. Actually, the time to start the finishing process is before you even begin. Your finishes will improve and you'll get immediate results when you consider two important factors: • Wood Selection - When you plan to color your project with stain or dye, choose wood species that don't Getting your wood ready to finish Is perhaps the most blotch. (I'll cover this topic in the next installment.) Once Important step to a beautiful finish. Here I'm examining you select a wood type, match as closely as possible the a board for dings, scratches and gouges by looking at It color of those boards that line up side by side. from a low angle. The light fixture In the bottom left cor· • Finish Selection - Will your project get an all­ ner of the photo really makes these defects jump out. paint finish; a natural, stained or colored finish; and will the final finish be oil or some type of clear top coat such as go about all this, and there are sure to be some who don't polyurethane, shellac, varnish or lacquer? entirely agree with my methods. It's a case of what works These factors, along with preparing the surface before for you; but believe me, what I recommend will work for applying any finish, are the important first steps in the fin­ you, and it is entirely practical and efficient. ishing process. Here's how I do it: It's best to rid your materials of mill marks, those tiny bumps or lines caused by machinery, Finish No Wood Before It's Time before you assemble your projects. Do this with the mater­ Because our first commandment for finishing involves ial flat on your bench, working on it at a convenient height. wood preparation, it's time to have an attitude check. Much Eliminate them by sanding or using a scraper. If you are of wood preparation is sanding, and we can agree that sand­ among the initiated who know how to sharpen or put an ing is near univetsally hated. It's boring, it's tedious and if edge on these tools, use them. But if you are among the 19 there's more then 20 minutes worth, it's hard work. out of 20 woodworkers who don't, you'll be sanding those The good news is you're probably working too hard at miniature peaks and valleys flat. We'll get into sanding a sanding, and there's a good chance your next sanding job little later; but the point is, get rid of the machining marks might get easier if you just read on. while it's easy on you, before assembly. Like so much in First, let's look at what we want to accomplish during woodworking, always think ahead! wood preparation. This includes removing dents, gouges Dents and gouges can happen during the building and errant dried glue, removing washboard marks left from process. A dent- a depression where no wood fiber is bro­ planing or jointing the wood, fixing router bit bum marks, ken or lost - can be easily fixed if not too severe using a and sanding to prepare the surface to accept the finish. hot iron and damp rag. A gouge, on the other hand, consists It's important to eliminate these imperfections. The eye of torn or missing fibers and is a larger problem. If superfi­ is drawn to dips, dents, dings and gouges - those flaws cial, say less than 1/64", you can sand (or scrape) it out. If that otherwise break an uninterrupted flat surface. A good deeper, you'll need to use some sort of filler. finish requires as flat and smooth a surface as possible. Using filler is a compromise because you rarely match the color of the wood. The other problem, of course, is that How to Eliminate Flaws stain never takes to putty in the same way it is absorbed by Let me say straight out that there is more than one way to the wood. When applying filler, always use a putty knife 32 Popular Woodworking Aside from the convenience and health benefits of keeping dust Steaming Out out of the air you're breathing, Some of the products you can use to fill Dents small holes. these sanders with dust-collection If there are minor miracles In the work more efficiently and increase world, steaming a dent out of How to Fill the life of the sandpaper you use. wood is surely one. Here's how to Small Holes By extracting the sanding dust do it. Simply take a clothes Iron For small filling jobs, like a set from the surface, the sandpaper set to Its highest setting, wet a nail, It's often best to wait until doesn't load up with dust (when clean rag, place it over the dent the finish job is complete and then this happens you are sanding the and apply the hot iron. Hold It in use a wax crayon (even your dust, not the wood surface). These place for at least 10 seconds to child's crayons can do the job In a machines also vacuum up pieces allow the Iron to force the steam pinch). At this stage you know of broken-off abrasive, which if left Into the wood fibers below. what the final wood color is so the behind when you switch to the Chances are you can swell the guesswork is taken out of match­ next finer grit of sandpaper, will crushed fibers that made the dent Ing the filler color to the wood. impart coarser scratches to the and restore the surface to Its origi­ Filler used before finishing not only wood surface when the loose grit nal, undented state. If your first fills the gouge or hole, it also fills gets under the the sanding pad. attempt doesn't work, try it a sec­ the grain surrounding the gouge. That's one reason to sweep or ond or third time. Fortunately, So if you must use a filler, handle blow off all the dust from your pro­ wood fibers have a memory, and as it carefully and apply It only in the ject when you switch to the next long as the fibers are intact, they opening needing repair. finer grit sandpaper. can return to their original state. and force the material into the opening. And always leave been wiped on. After you've identified a spot, dampen it a little proud of the surface so it can be sanded flush later. more until the glue is soft enough to remove. I like to use a single-edge safety razor blade to scrape off the softened Get the Glue Out glue. Then clean the area with the wet rag. Even after what you think is a thorough sanding, you might find glue near joints or smeared on a surface after you've Choosing Hand-Held Sanders started staining or top-coating. First use an ounce of pre­ Power sanding machines have made the unwelcome chore vention and be careful not to allow glue to get smeared on of sanding much easier. When used properly, you'll get your work. When it does, clean it up right away with a good result'S. Of the three common types of sanders, belt, clean wet rag. And make sure you wash the area complete­ orbital and random orbit, you should choose the latter. ly, not just wipe it off, which could compound the problem Why? Because random orbit sanders are more aggressive by smearing the glue even more. and efficient than an orbital sander and they don't leave I've had more than one honest disagreement with other obvious swirl marks. Also, the random orbit sander is not woodworkers about the water and rag clean-up method. I as aggressive as the belt sander, which is almost always too still recommend it, and here's why: If you wait until the aggressive and can ruin a project in the blink of an eye. glue is dry you risk either tearing out wood fibers when Belt sanders are great for removing stock quickly doing scraping, or just making the sanding harder. If you scrape rough work, but don't use one on a surface that will be fin­ the glue when it's soft, you fail to remove the partially dry ished! That said, there are some woodworkers who know glue that has soaked into the wood. I think those who have how to keep this powerful tool absolutely flat while apply­ not successfully used the water and rag method have sim­ ing uniform speed and pressure. If you don't like playing ply not been thorough or aggressive enough. fast and loose with your projects, keep your belt sander on If you put yourself in the sloppy category, or if you just the shelf and use it for other work. It's too easy to oversand, want to make dam sure you haven't left any glue behind, leaving what I call a dished, or hollowed-out look.