As a result, choosing the right sandpaper grits and using them correctly is something of an art form. You need to hit a sweet spot that's neither too coarse nor too fine. Sandpaper grit is sized by a gauge number, with lower numbers signifying larger, coarser grits. For example, or grit sandpaper is a very coarse, rough sandpaper, while the 1,grit paper is extremely fine with very small abrasive particles.
The grit number of sandpaper is almost always clearly printed on the back of the sandpaper itself. Grit numbers range from 24 all the way up to 1, although most people will never use grits at the top or bottom of this scale. It's often thought that the grit number refers to the number of grit particles per square inch.
Not so. Rather, the number scale refers to the number of holes per square inch in the screens that are used when sieving the abrasive grains during the sandpaper's manufacture. For example, in grit sandpaper, the abrasive particles used in the paper were sieved through a screen that had 60 holes per square inch. Coarser, or lower-number grit, sandpaper removes wood and other materials faster and with less effort than finer sandpaper.
It does this by cutting the fibers on the material's surface. Aggressive scratching is desired when you want to remove much material or to create a rounded edge, or to remove old paint or blemishes. But the coarse sandpaper also leaves deep scratches.
At the other end of the spectrum, very fine sandpaper removes a tiny amount of material, with the effect of smoothing the surface. The finer the paper, the smoother the surface. The concern here is that if you switch to a fine paper too soon, you'll spend a lot of time sanding to get the results you want.
Also, sanding wood with too-fine paper, or sanding too much, can actually burnish or create a shine to the surface. This produces overworked areas that can hinder the absorption of stains and other finishes. Excessively sanded wood can create a blotchy appearance when stained and finished.
The trick, then, is to start with the highest grit coarsest sandpaper that will meet your needs relatively quickly, then move up to progressively higher grits smoother papers as the surface gets closer to the finished product—and to stop when it's smooth enough for your liking. While you can find many differently graded sandpapers available, most sanding projects call for papers in the following grit ranges:.
Sandpaper grit in these low numbers cuts through old paint and rough edges with ease. It can also take off enough wood to shape and round edges. Continue on to grit if you're using a stain or dye. These colorants tend to amplify swirl or scratch marks. Sanding to grit creates a glasslike surface, but also one that accepts little stain, if that's your goal.
Which sandpaper grits should I use? Save Pin FB More. Q: In project articles, you often say "sand to grit. All rights reserved.
Close Sign in. In addition, some papers are treated with zinc stearate, a soapy substance that prevents clogging. Don't use these so-called "nonloading" papers with water-based finishes, however; stearates can prevent the finish from adhering properly.
Once, sandpaper came in two colors: black or tan. In recent years, manufacturers have begun to tint their abrasives with dyes of lilac, teal, or burnt umber to make them stand out from the competition.
Now only the natural abrasives — garnet and emery — can be counted on to always display their true colors. Following is a guide to the six most common types. Excellent for sanding or polishing metal; too soft for other uses. Comes on flexible cloth backing.
Extremely hard; sharp enough to cut glass, but wears quickly. Best for smoothing joint compound and removing dust nibs between coats of finish.
Extra-fine grits are used for wet sanding the final finish coat. The jack-of-all-trades abrasive; great for hand or power sanding on wood, paint, or metal. Not as sharp as silicon carbide, but lasts longer. Tougher, more durable, and more expensive than other abrasives; often bonded chemically with aluminum oxide.
Used primarily on belts and discs for power sanding. An alloy of aluminum oxide and zirconium oxide. Sharp, hard, and durable, it cuts faster and lasts longer than aluminum oxide, but isn't as long-lived as ceramic. Found mostly on belts and discs for machine sanding. Knowing what grit to start with and when to stop is the key to a perfect sanding job. Starting with too coarse a grit leaves deep scratches that are tedious to sand out.
But starting with too fine a grit eats up time and paper, as does finishing up with a finer paper than is necessary for the job. Here are some guidelines:. Time was you could read the back of a sheet of sandpaper like a book. Printed there were the grit size and type, the weight of the paper, the kind of glue used, and whether the sheet was open or closed coat.
Now, about the only thing you'll consistently find, other than the manufacturer's logo, is the grit size. But even that bit of information can be confusing.
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