Read the article below. Then watch the 2 videos at the bottom of the page.

The most important and most easily overlooked step in finishing is wood prep. This is because a quality finish, especially a high gloss finish, accents everything: the wood grain, the figure of the wood, the depth of the wood as seen in the curves of the neck, but also every cross-grain sanding scratch, every dent, every tear-out, and every left over bit of glue squeeze-out. Even otherwise unnoticed depressions sanded into the neck profile will jump out once the finish is applied. Inspect your guitar Take some time and carefully inspect the guitar for blemishes. A well-lit workspace goes a long way in identifying where you need to concentrate your efforts. Dampening (not wetting) a rag with mineral spirits or naptha and wiping down the guitar will mimic the accenting effect of finish so you can more easily identify areas that need special attention. Water will also work but not as well since water also raises the grain. "Steam out" dents Dents can be "steamed out." Knowing the difference between a dent and a tear-out is important. Dents are the result of bumping the guitar into the edge of the workbench or (frequently for me!) dropping a hard tool onto the soft wood of the soundboard. Dents are areas where the wood grain has simply compressed rather than a tear-out, where a chunk of wood has gone missing. This can sometimes be remedied or atleast partially brought back to level by placing a wet cloth or piece of cardboard over the dent and pressing a hot solder iron (23 watts is enough) into the cloth or cardboard. Be diligent to target only the area in question and not the surrounding wood. If you're at all like me you should find a few of these on your soundboard but not likely on the hardwood parts of your guitar. Fill tear-outs Tear-outs must be filled. On dark hardwoods (ebony, rosewood, walnut) this is easy. Find a matching piece of scrap around your shop (wood shavings from your hand plane are good candidates for filler material), tailor it to fit and glue in place with a drop of Cyanoacrylate glue (AKA Superglue). Fill any gaps around the filler scrap with fine ebony dust and more CA glue, then sand the area level. I prefer the water thin CA because it gets into all the spaces between the ebony dust for a seamless fill.

Wood shavings from your hand plane are good candidates for filler material

Micro tear-outs can be filled with just ebony dust and CA glue on dark woods. Counter-intuitively, walnut dust filler on a walnut guitar, or rosewood dust on a rosewood guitar is often a more noticeable repair than ebony dust on either one. The reason is because wood dust lacks grain lines and therefore appears lighter than the surrounding wood. The ebony dust will often blend in with the grain lines and the dark bands that rosewood and even walnut sometimes has. Soundboard tear-outs are more difficult because CA glue tends to soak into spruce and stain the area deeply making it difficult or impossible to sand out the stain. You can use Titebond instead but, unless the filler piece fits perfectly, this will leave a glue line. If I value my time, and depending on how large or noticeable the repair is, I will use the CA or the titebond method despite their drawbacks. Also realize that, in many cases, a visible repair is less aesthetically pleasing than the blemish would be if it was left alone. Sometimes it is best just to leave it be and call it "Character." Sand to 120 Grit Once the instrument is free of eye sores, or nearly so, it is time to sand all surfaces smooth. At this point always sand with the grain. Sanding across the grain leaves deep scratches that are difficult to remove. Not only does sanding with the grain limit these deep scratches, but any scratches that do remain are far less apparent to the eye because they follow a grain line. In some cases where heavy sanding is needed, I will sand at a slight angle to the grain. This speeds up the sanding a little bit without leaving cross-grain marks. Even so, I still finish with several strokes directly with the grain to remove the slight angle marks.

Always sand with the grain before proceeding up the grits.

Start with 120 grit and take your time. Always use some sort of sanding "block" behind the paper. Pressing into the paper with just your fingers digs depressions into the wood rather than sanding a level surface. I keep about a dozen sanding "blocks" on hand for different situations. For large, gently curved surfaces like the domed plates of the top and back, I use a large, soft block that can conform to the doming of the surface.

For tight, inside curves like the waist of the sides, I use a variety of wooden dowels or large round sharpie markers. For tight areas, like the area of the sides around the heel, I use small flat blocks and sanding sticks (the kind you can get from Stewmac or Woodcraft). Hard, flat blocks are for flat areas, like the peghead and heelcap, and for the broad, outside curves of the sides. The only part of the guitar where I don't use a sanding block of any kind is the shaft of the neck. I clamp the guitar down to the workbench so that the neck overhangs, and using a long strip of sandpaper held taut at both sides, I sand vigorously from headstock to heel just like we did in the neck carving lesson. Sand to 220 - 320 Grit Repeat the sanding process with 220 grit sandpaper. The objective here is simply to remove the 120 grit sanding scratches so you need not spend a lot of time on any one particular area. You may also round over all edges of the guitar at this time with the 220 grit paper and a very soft block or backing, such as a kitchen sponge. Rounded edges are not only aesthetically appealing. They are also critical to proper finishing. It is nearly impossible not to sand through the finish on a sharp 90 degree edge. The edges, however, only need to be rounded slightly to mitigate this, but be sure to get every edge: soundboard, back, peghead, and the heelcap.

If you are satisfied with your results from the 220 grit paper you can stop there. Sometimes I like to sand the soundboard up to 320 grit, but I won't go any further than that. Sanding with 400 grit and finer is unnecessary and you can actually produce TOO smooth of a surface. Most finishes need some "roughness" to adhere to. Try applying finish to glass and you will know what I mean.

Notes on Scrapers Some people advocate the use of scrapers in preparation for finishing. If tuned properly and used properly some woodworkers claim they can give smoother and quicker results than sandpaper. Personally, I find them incredibly useful and a pleasure to use during the build process but of limited use in preparation for finishing guitars. It is difficult to maintain the intended flatness or curvature of large surfaces with scrapers. However, they can be useful in flat, narrow areas like the sides of the peghead. I would recommend strictly sticking with sandpaper for finish preparation, but experiment with scrapers if your time and your budget allows. WORK-SPACE PREP At this point, as you prepare for the first coat, it is prudent to clear your workspace of clutter and vac up fine wood dust that can become airborne and cling to a wet finish.

Hang your guitar My finishing setup for Tru-oil and any hand-applied finish involves hanging the guitar from the ceiling on a swivel so I can freely rotate the instrument while I work. I use a screw eye and a swivel snap hook purchased from the local hardware store.

Screw Eye

Swivel Snap Hook

This setup, of course, can easily be removed when you are not in finishing mode. This method allows me to apply coats quickly over the entire instrument without having to rest any part of the instrument on the workbench and risk marring the finish. It also allows me to quickly and effectively inspect the guitar for runs and uneven coating without having to pick the instrument up. This setup is not without its drawbacks, however. Hand applied finishes require hard application pressure and lots of elbow grease, and not having a hard surface, such as the workbench, to bear the instrument against makes this more difficult. You will have to decide for yourself whether the pros outweigh the cons. At the very least, this setup is useful for inspecting, dusting and de-greasing the guitar prior to applying coats. Create a handle Also for my setup, I cut a length of flexible coat hangar material (about 16") and bend it into a "V" shape. I stick the ends of the coat hangar material into each E-string hole and bend them slightly to hold. Now I have a handle to grip and manipulate the guitar freely in space without having to touch it.

Let there be light! Proper lighting is never more important than during the finishing stage. As a bare minimum, you should have atleast 2 powerful light sources positioned in different parts of the room at angles to each other. This reduces shadows. I use "daylight" or "natural light" bulbs.

Last but certainly not least, there is natural light, as in the light from the sun! I am fortunate enough to be working in a space where there is plenty of natural light. Position your finishing setup close to windows. Natural light is the kind of light that your guitar will most often be scrutinized under, so incorporate as much natural light into your setup as your situation allows. That is not to say that you can't still produce excellent results in a windowless situation. I know not everyone is so lucky as to have natural light in their shop, but if you do have a window or two, use them! Now watch these 2 videos for further clarification:

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Wood prep

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