First, let's get the scary stuff out of the way. Let's say you've got a nice piece of trim or baseboard you need to sand in preparation for painting. Choose the wrong type of sandpaper grade, and you can either end up gouging nonrepairable grooves in your nice trim or sanding from now until infinity and get nothing accomplished.
Welcome to the world of sandpaper grit.
Sandpaper Grit Defined
When you're at the hardware store, procrastinating about the monster sanding job you've got back at home, naturally you may eye the roughest sandpaper and think: Well, that'll do the trick, why not that?
Grit is expressed in the form of numbers on back of the paper. These numbers range from 24 all the way up to 1,000, though in practice most homeowners will never use grits at the top or bottom of the scale.
Grit does not mean the number of grains deposited on a square inch of paper. Rather, it refers to the number of holes per square inch in the screen when sieving abrasive grains.
In fact, grit sizing is counter-intuitive. The bigger the number, the smoother the paper. The lower the number, the coarser the paper. So, the best way to look at this is simply to remember that the numbering runs backwards.
Why Have Different Sandpaper Grits?Simple: coarser paper removes the unwanted material faster and with less effort. Yet coarse sandpaper from #50 on downward can easily damage your project - all in the name of speed. It's wishful thinking to plan on sanding out your gouges by stepping down to finer and finer grades of sandpaper. You're just creating more work for yourself. So, the best thing to do is pick a sandpaper grit that is appropriate for the job.
(Compare Prices for Different Grades of Sandpaper - Buy Direct)
A Range of Sandpaper Grits / GradesWhile you can find scores of differently graded sandpaper available, you will probably only use a small handful:
- #50-#30: Very Coarse Grit - Rips off peeling paint and extraneous materials with ease. Also risks damaging your project. Not recommending for fine pieces such as trim or furniture.
- #80-#60: Medium Grit - Your universal grades of sandpaper. It's hard to go wrong with sandpaper grits in this range. You can work down difficult materials by applying more elbow grease to the job. Or, you can preserve fine materials by letting up on the pressure.
- #180-#100: Fine - You would never use these grades of sandpaper on the first run-though. Grits in this range are always - and I mean always used for second or third sandings. Sometimes, fine grit sandpaper is used to "roughen" down glossy paint in preparation for applying another coat of paint.