Wood sanders........seem simple.....just buy sand paper and your off. Of course, like everything else I do, I "needs" to know more. So that I can access this info later (when I most need it) and to share with you, I give the following mini-blurb about wood sanding and sanders. Please note that I am not a professional woodworker and the following only represents my opinions and experience.
Safety
Sanding is often considered a safe task relative to a number of other tasks that are done around the woodshop. It doesn’t give the feel of danger as say using an 8000 rpm spinning metal toothed blade of death (read table saw) to destroy some type of material. But safety is just as important when sanding as many other tasks. Two areas of concern are self-sanding and dust.
Self-sanding just basically qualifies as taking the sander/paper to your body. While you may want to remove your fingerprints so you can be a master thief (sanding would do this for you but I could think of easier/less dangerous ways), dropping a running power sander on bare skin can do some serious damage. Between friction and the rough nature of the sanding materials, you can quite inadvertently remove flesh.
Dust is the subtle killer of sanding. Since we can’t see it (for small particles) or often don’t notice it (for larger particles) because it’s not as big as the material we are working on, it’s easy to forget that this stuff is around until you go to clean up at the end of the day. Keep the laws of mass and energy conservation in mind here. Sanding produces heat and dust that are directly proportional to the amount of sanding done. The material being removed doesn’t magically disappear into the ether. It most often floats in the space you inhabit and then you go and do some bone-headed thing like breathing and this dust gets in your lungs. I don’t know if they’ve created the phenomenon of Wood Lung (vs. Black Lung), but I’d rather not give them an excuse. Also keep in mind that dust can jack up your eyes as well.
Uses – things to accomplish
Shaping is basically the act of taking a piece of stock/wood and changing its shape. For example, standard wood from Lowes tends to be rectangular in shape. Sanding the hard corners of this standard stock to produce softer edges would qualify as shaping. Of course shaping can be much more drastic, for example, taking a square piece of plywood and sanding it into a circle (Note: there are better ways to do this, but that’s another story).
Cleaning would constitute using a sanding material to remove unwanted “stuff” from your work piece. This could include things like paint, varnish, crayon/pencil marks. This use for sanding can require some pretty dedicated focus to do correctly. If you’re re-finishing your cabinets and not paying enough attention to the sanding, you can easily gouge or otherwise mar your very expensive material.
Smoothing (or finishing) can be considered a hybrid of shaping and cleaning. The purpose is to remove any “roughness” to the material being worked on. Most often this is done to prepare a material/surface for finishing (painting, staining, varnish, etc.). Smoothing is often the most delicate use of sanding as it’s often one of the last things done to raw material and can have numerous effects on how a follow up process behaves (for example, staining often looks better when the wood surface isn’t glass smooth, rougher surfaces tend to accept stain better and provide more depth of color and visual texture)
SandpaperSandpaper comes in many styles. Examples include square sheets, sanding blocks, round sheets, continuous loops or belts, discs, sticks, and probably many others. The basics here are to pick the style that fits the tool in use (see the instruction manual for whatever power tool you are using). When in doubt, square sheets will get you by as long as you are willing to put in the elbow grease to hand sand everything.
GritSand paper is often categorized by grit. The rule of thumb here is the higher the number, the smoother the resulting surface should be AND the less material removed per pass. For cleaning and shaping, you’ll often want low grit numbers (between 60 and 120, though for really good gouging you could go with 30). For smoothing, often it’s best to start low and do multiple passes with increasing grit counts. I have heard this referred to as “going through the grits”. Three passes tends to be the standard recommendation (say a 60, 120, then say a 180 or more for a very smooth finish).
Sandpaper can often “clog”. This phrase means that material being removed from the wood is getting stuck between the individual rough pieces of the sandpaper. This causes the surface of the paper to become smooth (exact opposite of what you want) and produces more heat (which we often want to avoid). Be sure to shake or blow some compressed air on the sandpaper to keep the paper unclogged.
Grit MaterialThe rough junk on the sandpaper can be made of a number of different materials. For most simple jobs aluminum oxide will work fine and works on both common woods and most metals. For exotic woods (rosewood, maple, redwood, Sitka spruce, or a wood that is just plain hard to pronounce) or unusual applications (wet-sanding or high-pressure sanding), you might want to do additional research on alternative materials (like garnet for example).
More info:
WoodZone and
WikipediaPower Sanders
TypesBelt sanders remind me of tank treads. A continuous loop of one-sided sandpaper is rotated to produce a continuously moving sanding surface. Belt sanders excel at removing large amounts of material without breaking your arm. So if you want to clean a surface, a belt sander would be the way to go.
Disc sanders spin (like a car tire) a circular pad to produce the sanding motion. For non-commercial usage, disc sanders tend be bench mounted, though you can buy portable power versions. Disc sanders excel at removing materials like belt sanders (though IMHO, I prefer belt over a disc for striping) and also provide better control for shaping (turning that square piece of plywood into a circle).
Orbital and
random orbital sanders move the sanding surface in an orbit (think “wax-on, wax-off” from The Karate Kid); there is generally no spin involved (though you can find spinning orbital sanders). These types of sanders excel at finishing/smoothing work.
Bench sanders are fixed machines that are designed to be stationary (as in “stuck to the workbench). It is common to find one device that provides both a belt sander and a disc sander, though you can also purchase single purpose bench models.
More Info:
Wikipedia,
Essortment (quick belt vs. disc discussion),
Extreme How-To
