Abrasives

Back to Materials Department

O.K., let's be realistic. Chances are, if you're reading this, it's not for enjoyment. I have yet to meet a woodworker who actually enjoys sanding, much less reading about sanding. In light of this, I've organized the information below for quick access, so the reader can get in and get out quickly. There's a few paragraphs with handy tables for the important stuff, and a glossary of sanding-related terminology to organize most of what's left over. Just in case you are one of the rare few who perhaps might enjoy a little further illumination on the necessary evil we woodworkers call sanding, I've attempted to detail a foolproof sanding procedure on the Introduction to Wood Finishing page, under the heading The Process.

Safety First!
Safety in the workshop is YOUR RESPONSIBILITY alone; I make no warranty as to the safety of any technique or tool shown or described on this site.  Before beginning any project, you must understand woodshop safety, know how to safely operate any machinery that is to be used in the project, and understand the safe use and any potential safety hazards involved in the use of all materials to be used in the project.  See the General Safety Notice and the Chemical Safety Note for additional information.

T Y P E S   O F   A B R A S I V E S 

 Terminology

Abrasives are broken down into three types, according to how they are used. Loose abrasives are just particles of loose grit, used mostly for sandblasting and similar industrial uses. Bonded abrasives include abrasive cutoff-saw blades, and grinding stones, wheels and disks. Coated abrasives include sandpaper, sanding belts, sanding sponges, carbide rasps, and diamond pads.

 Abrasive Materials

There are many different materials used to make abrasives, each with its own advantages and disadvantages. The most common abrasives for use on wood are aluminum oxide (marked on the back of sandpaper as AlO), silicon carbide (SiC), garnet (Gar), and steel wool. The properties of these are described in more detail in the table below. Abrasive near the top of the table are those most commonly used in woodwork; those below the double line are used, but less often.

 Grit Numbers and Grading Systems

There are four different grading systems for grading the fineness of abrasives: ANSI / CAMI for American abrasives, ISO / FEPA for European abrasives, JIS for abrasives made in Japan, and the average particle size (in microns) which is the measurement basis used to compare all of the systems. For grades 220 and coarser, CAMI, FEPA and JIS grades are nearly identical, but when you get into the finer grit sizes, the differences become increasingly large, as shown on the chart below. The different systems also vary in the range of grit sizes that are allowed in a particular grade, with FEPA and JIS tending to sort the finer grits a little more precisely.

 Paper and Other Backing Types

In addition to different grades of abrasive grit, sandpaper is available with a number of grades of paper backing, designated by letters A through F, from lightest (most flexible) to heaviest (stiff and tear-resistant. Cloth backings are graded with the letters J,X,Y,T and M, from lightest to heaviest. Also available are fiber backings and combination backings such as cloth with foam, mostly used for specialty applications. In addition to different weights, backing materials come in standard and waterproof varieties. Most paper-backed abrasives finer than #600 (CAMI) use waterproof paper, since these ultra-fine grits clog easily if not used with a lubricant of some sort.

 Adhesives and Coatings Used in Sandpaper

Several different adhesives are used to glue abrasives to their backings to make sandpaper. Different resins, such as phenolics and epoxies, as well as hide glue and even metal platings are used for the different properties they give to the abrasive. Most woodworking sandpapers use resins to bond the grit to the sandpaper, but some flexible abrasives use epoxies and other flexible materials to give them the ability to conform to the surface being sanded as well as to cushion the individual abrasive particles, thus giving a smoother finish on the wood.

To further enhance the cutting properties of different abrasives, coatings are sometimes applied over the finished abrasive. These may enhance the wet-sanding properties, prevent finishes from clogging the paper, or change the color of the abrasive (for color coding finer grits, for example). A common coating for many woodworking sandpapers is zinc stearate, a white, soapy substance that prevents the paper from clogging when dry-sanding finishes.

 Open vs. Closed Coat Sandpapers

Open coat sandpaper is the type used for sanding wood and other low-density materials. The term refers to the space between the grains of abrasive, which allows room for the swarf (sanding dust) to collect without clogging the paper. Closed coat sandpaper is used mostly on denser materials such as metal, which abrades more slowly. Closed coat paper can also be used with a lubricant such as water, most commonly when sanding a finished surface.

S A N D I N G   G L O S S A R Y 

Abralon®

Brand of abrasives made by Mirka. Uses silicon carbide abrasive specially bonded to a woven fabric mesh and backed by an open-cell foam pad. Can be used wet or dry, and combines the properties of sandpaper and non-woven abrasives. Available in grades ranging from 180 to 4000 grit (CAMI)

Alumina

Synthetically produced aluminum oxide, typically harder and more pure than aluminum oxide that is refined from bauxite.

Alumina Zirconia

The toughest of the aluminum oxide based abrasives. Commonly used for high-speed grinding and polishing of metals.

Aluminum Oxide (AlO)

Chemical composition Al₂O₃. The abrasive most commonly found on power sanding equipment, designated on the back of sandpaper as "AlO". Aluminum oxide is friable, meaning its crystals fracture as they wear out, producing new sharp cutting surfaces. This allows the sandpaper to continue cutting aggressively much longer than other abrasives. See also Alumina, Alumina Zirconia, Ceramic Aluminum Oxide, Garnet, Silicon Carbide.

ANSI

American National Standards Institute, which regulates industrial standards on products produced in the U.S.A., including abrasive grades. See also CAMI, FEPA, JIS.

Belt Cleaning Stick

See Rubber Cleaning Stick / Block

Belt Sander

A power sander that uses a loop of abrasive driven between two rollers. Belt sanders are very aggressive, and are mostly used for stock removal. Due to the linear sanding motion, belt sanders tend to leave a prominent scratch pattern of parallel lines. Widths of sanding belts for belt sanders range from less than 1" for benchtop detail sanders, to 2" to 4" for portable sanders, and 6" to 53" for stationary and wide-belt sanding machines. See also Detail Sander, Drum Sander, Edge Sander, Oscillating.

Block

See Sanding Block

Boron Carbide

A very hard abrasive used mostly in industrial applications for grinding metals.

Boron Nitride

See Cubic Boron Nitride

Bronze Wool

Similar to steel wool but made of bronze; used in refinishing to strip old finishes. Steel wool sheds fibers, which may stick in the wood and rust later, forming a stain. Bronze has a reduced tendency to oxidize, so it causes fewer problems for the refinisher. See also Non-Woven Abrasive.

Buffer / Polisher

A powered tool used with a pad or a wheel for polishing and buffing finishes and metals. Portable buffers often feature a 6" to 8" round pad that moves in a random-orbital motion and at variable speed. The pad can be fitted with various abrasives, polishing cloths, or lambswool covers as needed. Stationary buffers usually feature a wheel of muslin or felt, or sometimes a soft brush, against which the item to be buffed is held.

Buffing

The final process of polishing, in which a non-abrasive pad is used to remove excess polishing compound or waxy residue and burnish the surface for maximum shine. See also Buffing Compound, Rubbing Compound.

Buffing Compound

A paste similar in function to rouge. Contains microabrasives and, frequently, wax to fill in any remaining ultra-fine scratches. Used to remove fine scratches when polishing a finish that has been rubbed out.

Burnisher

A tool used for burnishing. In woodworking, this can be a scraper burnisher, used for raising a bur on cabinet scrapers; or an agate burnisher for putting the final shine on objects that have been gilt using the water process.

Burnish, Burnishing

The process of smoothing a malleable surface by rubbing it with a harder, normally non-abrasive material. This results in any high or rough spots being rolled out flat by the rubbing action. Burnishing is essentially a cold forging process, but it can be done on wood and finishes as well as on metal. See also Burnisher, Scraper, Worn Out.

CAMI

Coated Abrasives Manufacturers' Institute, now merged into the Unified Abrasives Manufacturers' Association. ANSI / CAMI standards are used to regulate the grit sizes of most North American abrasives.

Carbide

A chemical compound consisting of a metal and carbon. In woodwork, carbides are used mostly as abrasives and as a durable insert for the cutting edges of tools. See also the Abrasive Materials chart, above.

Carborundum

A trademarked name for silicon carbide.

Ceramic Aluminum Oxide

Aluminum oxide that has been treated in such a way as to make a very tough ceramic-like abrasive. Used in high-performance abrasive sheets and sharpening stones.

Closed Coat

Designates sandpaper with no extra space between the grains. Tends to clog very quickly on wood, but is used widely for sanding metals and for wet sanding finishes.

Coated Abrasives

The "proper" term for sandpaper and sandpaper-like abrasive materials, where abrasive particles are applied as a coating onto a paper, cloth, or other backing.

Coarse

A non-technical grade used mostly on poor quality sandpapers. Approximately equivalent to P80.

Cork Block

A block of cork; used as a hard sanding block and when making custom-fitted sanding blocks, as for sanding moldings.  See also Tadpole Sander.

Corundum (Cor)

Another name for natural aluminum oxide and its gemstone forms, sapphire and ruby.

Cubic Boron Nitride (CBN)

One of the hardest abrasives, classified as superabrasives. Used for grinding steel at high speed (as when sharpening woodturning tools on a bench grinder), as diamonds tend to break down quickly under high-temperature high-pressure loads when in contact with iron.

Degloss, De-gloss

To remove the gloss, or shine, before coating with a finish or paint, to improve the adhesion between separate coats. Deglossing can be done with fine sandpaper (320 to 400 grit), steel wool (#0000), non-woven abrasive pads (maroon or gray), or, for paint preparation, with a liquid cleaner / deglosser such as TSP (trisodium phosphate).

Detail Sander, Sanding Pencil

A roughly pencil-shaped tool used to sand small parts or in difficult-to-reach areas. Has a spring-loaded end that applies tension to a narrow sanding belt that wraps around the tool lengthwise. Available in ¼" wide and ½" wide sizes, and belts are available in several grits.

Dewhiskering

See Raising the Grain.

Diamond

The hardest material; a crystalline form of pure carbon. Synthetic diamonds are widely used as abrasives for cutting hard materials, and are classified as superabrasives. See also Cubic Boron Nitride.

Disk Sander

A powered sander that uses a rotating disk of abrasive to perform stock removal on wood. Available in diameters ranging from 6" to 18".  Often combined with a belt sander into a single stationary tool.

Drum Sander

A powered sander that uses a cylinder, or drum, covered in abrasive sheet to perform flattening and stock removal on wood. Drum sanders can be used like a thickness planer, but are slower to remove material; however, they do perform better at flattening wood, especially when making shop-made veneers. Available in widths from10" to over 50". See also Belt Sander, Sanding Drum.

Edge Sander

Basically a belt sander on its side, an edge sander is used for sanding edges rather than faces of boards. It features a table in front of the sanding belt upon which the wood can rest to ensure that the sanded edge is square to the face of the board. See also Oscillating, Sanding Drum, Spindle Sander.

Emery

A natural abrasive, composed mostly of mineral corundum (aluminum oxide), with iron minerals hematite and magnetite. Available in coarse (~36 grit), medium (~60 grit) and fine (~100 grit) varieties.

Felt Block

A block of hard or soft felt that can be used with sandpaper as a sanding block, or with rubbing compound for polishing or rubbing out a finish.

FEPA

The European Federation of Abrasives Producers. FEPA maintains the P-Standards issued by ISO and used to grade European abrasive grit sizes.

Fine

A non-technical grade used mostly on poor quality sandpapers. Approximately equivalent to P180.

Finish Sanding

The final few steps of sanding in preparation for finishing.  See also Sanding Schedule.

Fish Skin

A very early abrasive; the dried skin of eels, dogfish, sand sharks, or rays. Other early abrasives included emery, pumice blocks (holey stone), sandstone, and reeds such as horsetails.

Flap Sander

A powered sander that uses a drum with several strips or flaps of sheet abrasives attached to it to sand irregular or hollowed surfaces that would be difficult to sand with traditional power sanders. See also Sanding Stars

Friable

In abrasive compunds, a friable grit breaks down into smaller, but still sharp grains. Non-friable abrasives wear by the rounding of grit particles, so they will tend to burnish the surface more as they dull.

Garnet (G / Gar)

Chemical composition Al₃B₂Si₃O₁₂. Amber colored abrasive often used for the final sanding before applying a stain. Garnet is non-friable (its crystals wear out and become rounded), and dulls relatively quickly, leaving a much less visible scratch pattern on the wood, but burnishing the surface in the process.

Glass Paper

An English term for sandpaper, originating from the fact that early sandpaper was actually made with crushed glass or flint.

Gouges or Gouging

Furrows, ridges or curved scars left by the edges of sanding belts or disks. Particularly common with portable belt and disk sanders, but also poor quality random-orbital sanders.

Grade

The degree of fineness, or grit, of any abrasive material. Most sandpapers and grinding stones use a numbered grade such as #220, or P120. Steel wool uses low numbers such as #2 and #0000. Non-woven abrasives use a color-coding system to identify grades. Powdered pumice uses the 'F' system, with one 'F' indicating the coarse grade and 'FFFF' or '4F' indicating the finest grade.

ISO

The International Standards Organization, which sets standards for European products and industry. See also FEPA.

JIS

The Japanese Industrial Standards Committee; regulates standards on products produced in Japan, including abrasives and waterstones.

Lapping

The process of grinding a surface to make it perfectly flat; essentially a specialized form of honing, as when sharpening. A common method of lapping for woodworkers is to place sandpaper on a glass or granite plate, which provides a perfectly flat surface.

Macro- and Microgrit

Macrogrit is a technical term used by abrasives manufacturers to refer to any abrasive grade equivalent to 220 grit or coarser. Microgrits are grits 240 and finer.

Medium

A non-technical grade used mostly on poor quality sandpapers. Approximately equivalent to P120.

Mineral Oil, Paraffin Oil

An oil distilled from petroleum; completely nontoxic, non-drying, colorless, odorless, and essentially flavorless. Used as a finish on items that will come into contact with food, as a lubricant when rubbing out finishes, and medicinally as a laxative.

Non-Woven Abrasive

A spongy abrasive made from plastic with embedded abrasives; contains no metal. Used for scuff sanding between coats of finish, as it does not tend to cut through the finish on high spots or corners. Also known as synthetic steel wool, scrubbing pads, etc. and by the trademarked brand names Scotch-Brite and Bear-Tex. See also Bronze Wool, Steel Wool.

Open Coat

Designates sandpaper with about 70% of the paper's surface covered in abrasive grit. The extra space left between the grains provides a place for sanding dust (swarf) to collect without clogging the paper. See also Closed Coat.

Orbital Sander (1/4 Sheet Sander)

A powered sander used for final finishing. Uses ¼ of a standard 9" x 11" sheet of sandpaper which is held on by clips on each side of the sander's pad. Useful for easing (slightly rounding) corners, and as the final power sander before switching to sanding by hand (with the grain and using a sanding block) when the wood is to be dyed or stained.

Oscillating

Term used with reference to spindle sanders, edge sanders, and wide-belt sanders. These machines feature mechanisms that move the abrasive from side to side as they run. The purpose is to lessen the degree of linear scratching produced, but more importantly to spread the wear from sanding narrow pieces of wood, and especially glue lines, across a wider area of the abrasive.

Pad

See Sanding Pad

Pneumatic Sanding Drum

A sanding drum that is inflated by compressed air, and uses thin, relatively flexible sleeves of abrasive. By adjusting the pressure in the drum, the relative firmness of the sanding surface can be controlled. Used for sanding contoured surfaces and pillowing the faces of small parts, such as for intarsia. See also Flap Sander, Sanding Stars.

Polish, Polishing

Polishing is the process of removing very fine scratches and imperfections from a surface. Terminology varies, but polishing is usually considered to follow fine sanding or grinding, and is followed by buffing to produce the final glassy surface.  This can be done by buffing with a buffing compound, or when done as regular maintenance, with a non-abrasive or minimally abrasive compound called polish. See also Buffing, Buffing Compound, Burnishing, Rubbing Compound.

Polishing Compound

See Buffing Compound.

Profile Sander

A powered sander fitted with various attachments that allow it to sand molding profiles and similar surfaces. Uses a linear, reciprocating motion.  See also Cork Block, Tadpole Sander.

Pumice

Volcanic glass, usually finely powdered and used by finishers to rub out the final coat of fine finishes to produce a smooth, even gloss. Commonly available in two grades: 2F, which is fairly coarse, and 4F, which is an intermediate to fine grit. Rubbing with pumice is normally followed by a final polishing with rottenstone and wax.  Pumice is also available in solid blocks, which are used mostly for scrubbing griddles and ship's decks and as a callus remover at salons.

Raising the Grain or Dewhiskering

The process of wetting the wood and letting it dry, followed by a very light sanding to knock down the raised grain. When the regular sanding schedule has been completed, some of the wood's fibers have been left partially separated from the wood, and when the wood dries after being wet (by water or any finish containing water), these loose fibers stand up and leave the surface feeling rough. Raising the grain removes these loose fibers so a waterborne finish can be applied without raising any additional fibers. It is very important, when sanding the raised grain, not to over sand, which will create more loose fibers to rise the next time the wood is wet.

Random-orbital Sander (ROS)

A sander with a round pad attached to a motor by an eccentric bearing. This produces an orbital motion while the pad also spins slowly on the bearing. The idea is to achieve a more aggressive cutting action while leaving an inconspicuous scratch pattern. Random -orbital sanders are an intermediate step between stock removal with a drum or belt sander and finishing with an orbital sander or by hand.  See also Rotex Sander.

Resin

A term used for the aggregate of hardened pitch, dried sap, oils, and products of thermal degradation of wood (burning) that clings to cutters, especially on power tools, and clogs sandpaper on high-speed power sanders. When sanding, buildup of resin is best avoided by using proper sanding pressure and feed rates, and by changing to fresh abrasive as soon as the old abrasive shows signs of dulling. See also Rubber Cleaning Stick, Worn Out.

Rotex™ Sander

A proprietary power sander made by Festool that offers both random-orbital sanding motion and a gear-driven random-orbital-like sanding motion, called Rotex. Rotex sanding action combines much of the aggressive stock removal of a disk sander with the random sanding pattern and resistance to gouging of a random-orbital sander. Rotex sanding also avoids the swirl marks and curlicues left by random-orbital sanders when polishing metals and solid-surface countertops.

Rottenstone

A very fine powder, often made from diatomite, used as the final step in rubbing out a finish. Rubbing with rottenstone polishes away the scratches left after the use of pumice, and a final rubbing with rottenstone and wax can produce a very professional looking, if laborious, finish.

Rouge

A polishing compound consisting of a very fine abrasive in a base, such as wax, that acts both as a carrier and an adhesive to keep the abrasive on a cloth or felt pad or wheel. Rouges include white rouge and jeweler's rouge, and are detailed in the Hand Tools department under the heading Sharpening Tools.

Rub Out

To smooth a topcoat (clear finish, clear coat) by wet-sanding or by using pumice and rottenstone with a felt block and mineral oil or wax, or perhaps a commercially prepared rubbing compound. May be followed by buffing or polishing to increase the degree of shine. Rubbing out removes imperfections in the finish caused by dust settling onto the tacky finish, bugs, bubbles, and brush fibers.

Rubber Cleaning Stick or Block

A natural rubber stick, block, or pad; sometimes attached to a handle. Used for unclogging and cleaning sheet abrasives such as sanding belts, disks and drums, in order to prolong their working life. The rubber becomes sticky when heated by sanding friction, which allows it to effectively remove sanding dust, resin, glue, and other debris from the abrasive.

Rubbing Compound

A cutting compound similar to buffing compound, but designed more to cut into the finish than to polish it. Used to rub out a finish and for removal of deeper scratches when effecting a repair to a finish, and followed by using a buffing compound.

Sanding Block

Any block of material used to support sandpaper when sanding. Sanding blocks can be made from cork, felt, wood, Styrofoam, foam rubber, and more. They may be flat or contoured for sanding curved surfaces and moldings. A good sanding block provides a firm base for the sandpaper, but has some "give" to let the sandpaper conform slightly to high spots and corners, prolonging the sanding life of the paper. When sanding to remove high spots and flatten a surface, a harder faced block is used such as solid cork, or wood faced with a thin layer of cork, leather or rubber. When sanding to scuff a surface or to remove scratches from coarser grades of sandpaper, a medium-soft-faced sanding block is used, such as dense Styrofoam, medium foam rubber, or hard felt. For polishing or buffing, a soft block is generally used such as soft foam rubber, Styrofoam, or soft felt. See also Cork Block, Felt Block, Sanding Pad, Tadpole Sander.

Sanding Cord

A thin cord or narrow ribbon of material coated in abrasive. Used to sand inside v-cuts on spindles when refinishing, and similar jobs in difficult to reach spots. See also Detail Sander.

Sanding Drum

A cylinder, usually of rubber, fitted with a sleeve of abrasive and mounted on a shaft that either attaches directly to a motor or is held in the chuck of a drill press or portable drill. Used mostly for shaping and smoothing small parts and curved edges. See also Drum Sander, Pneumatic Sanding Drum, Sanding Stars.

Sanding Pad

Similar in function to a sanding block, a sanding pad is the surface of most portable power sanders to which the abrasive is attached.

Sanding Schedule or Sanding Sequence

The sequence of abrasive grits or grades that is used when sanding a particular item. The beginning abrasive material and grade, the ending material and grade, and whether all of the intermediate grades are used will depend on the material and the desired final result.

Sanding Sealer

A finishing sealer that contains a large proportion of solids and additives to make it sand easily without clogging the abrasive. Used to fill fine pores, prevent strongly colored woods from bleeding into neighboring woods while sanding, and to act as a sort of primer for a clear topcoat. Since sanding sealer is, after all, a sealer, it should not be used when a stain is to be applied.

Sanding Stars

A small, portable type of flap sander head made for use on a portable drill or drill press. Uses several roughly star-shaped disks of slitted abrasive. Available in a few grits for smoothing irregular and contoured surfaces prior to final sanding. See also Flap Sander, Detail Sander, Pneumatic Drum Sander.

Sanding String

See Sanding Cord

Sandpaper

A catch-all term for any coated abrasive sheet, but more specifically paper-backed abrasive. Sandpaper is made by coating paper with some form of glue; the first coat is called the make coat, then the abrasive is attached with the size coat. Abrasives used include aluminum oxide, silicon carbide, garnet, and many others; the three listed are the most commonly used in woodwork. Abrasives can be applied in open or closed coats. Open coat, which is used in woodworking, has about 70% of the surface covered, the open spaces between particles of grit providing a place for dust to collect until it can be cleared from under the working sandpaper. The weight, or thickness of paper used is indicated by letters: 'A' weight paper is thin and flexible, but tears easily on corners. 'C' weight paper is thicker and tougher, but cannot conform to fine details on carvings and moldings. Waterproof paper and glue is used for sandpaper that will be used for wet sanding. The coarseness of abrasive particles is given by the grit number of the sandpaper. The grits normally used range from about 20, extremely coarse, to about 2000, "super-duper fine". Woodworkers usually use grits from 60 to 320 on wood and 400 to 600 on finishes.

Scotch Brite™

See Non-Woven Abrasive

Scraper

Not an abrasive, but a hand tool used for smoothing in much the same way as sandpaper is. See the heading in the Hand Tools Department for more.

Scratch Pattern

The semi-random arrangement of scratches left on the wood by a particular combination of abrasive and sanding tool. An even scratch pattern, without scratches that are noticeably deeper than the others, is preferable to an uneven or coarse scratch pattern. Also, either a very even, parallel-to-the-grain scratch pattern or an even, random scratch pattern are preferred for finish sanding.

Scuff Sanding

See Degloss.

Sealer

See Sanding Sealer

Shark Skin

See Fish Skin.

Silicon Carbide (Carborundum) (SiC or SC)

Chemical composition SiC. Abrasive commonly used for fine grits (over 220) and on wet/dry sanding paper. Note that there is no 'e' in silicon; silicone is a completely different material. Silicon carbide is extremely hard, suiting it for sanding between coats of finishes, especially hard finishes like lacquer, but also non-friable, so it doesn't keep cutting as long as aluminum oxide. See also Aluminum Oxide, Garnet.

Spindle Sander

A stationary power sander that features a table with a sanding drum projecting upwards through it. Used for smoothing and contouring edges. See also Edge Sander, Oscillating, Sanding Drum.

Stearated Paper, Fre-Cut, No-Fil

Stearated paper, sold under the trademarked brands Fre-Cut and No-Fil, is sandpaper coated with stearate. Stearate is any of several white, powdery, soapy compounds - especially zinc stearate - applied to the surface of sandpaper to prevent finishes from sticking and clogging the paper. Stearates are highly water repellant, so when using them in conjunction with waterborne finishes, extreme caution should be exercised. See also Mineral Oil, Non-Woven Abrasive, Wet Sanding, Zinc Stearate.

Steel Wool

A fibrous steel product used as an abrasive and polishing agent. Used especially for scuff sanding between coats of finish and for scrubbing off varnish when stripping old finishes. Not recommended for use on bare wood, as steel wool sheds fibers into the wood that might rust later on. See also Bronze Wool, Non-Woven Abrasive.

Superabrasive

Any of a number of extremely hard abrasives, including diamond and cubic boron nitride (CBN).

Swarf

The particles removed from the work by an abrasive; grindings. See also Swoof.

Swirl Marks

Swirling or curlicue marks left by power sanding, particularly if low quality paper was used or too many grits were skipped in the sanding sequence.

Swirl Remover

See Buffing Compound

Swoof

Term for the particles of abrasive worn off during the sanding or grinding process. See also Swarf.

Synthetic Wool

See Non-Woven Abrasive

Tadpole Sander

Trademarked name for commercially made profiled rubber sanding block, sometimes shaped like a tadpole, used for hand-sanding profiled items such as moldings.

Tripoli

A rouge-like compound sometimes used to buff bare woods to a high gloss sheen. Used mostly on dense exotic woods or where a heavy finish is undesirable or unnecessary. Tripoli is detailed further in the Hand Tools department under the heading of Sharpening Tools.

Tungsten Carbide

Better known as the material from which many power tool cutters are made, tungsten carbide is also used to make coarse rasps for grinding and cutting wood, metal and ceramics.

Very Coarse, Very Fine

Non-technical grades used mostly on poor quality sandpapers. Approximately equivalent to P50 and P220, respectively.

Vitrified Abrasives

Abrasive materials, such as aluminum oxide, that are melted in a furnace to produce a solid mass which is then broken down and crushed into sharp-edged abrasive particles.

Wet Sanding

Sanding with a liquid lubricant, usually water or mineral oil. The lubricant carries away the swarf and prevents it from clogging the paper. If the purpose of the sanding is to level the surface of the finish, it may desirable to use stearated paper (dry) before wet sanding, as the liquid lubricant can pull the sandpaper down into low spots rather than allowing it to ride over them and just hit the high spots.

Wide Belt or Drum Sander

See Drum Sander, Belt Sander

Wool

See Bronze Wool, Non-Woven Abrasive, Steel Wool

Worn Out

The state of being used up; for sandpaper, it occurs when the paper no longer removes material efficiently. Using worn out or clogged sandpaper results in burnishing of the wood's surface, which can lead to burning the wood, poor staining properties, and poor adhesion of glues and finishes. A simple way to prevent using worn out abrasives is to change them as soon as they show signs of dulling. On power sanders used for stock removal, once you see the first signs of scorching that can't be attributed to high sanding pressure or too slow a feed rate, it's time to change. For finish sanding, try scribbling all over the wood with a soft, dull pencil. Once the sandpaper stops removing the pencil marks efficiently, it's time to change to fresh paper.

Zinc Stearate

Chemical composition Zn(C₁₈H₃₅O₂)². A white, highly hydrophobic powder with a soapy feel that is most often used as a lubricant. It is applied to sandpaper to prevent finish from sticking to it and clogging it. It is soluble in certain petroleum distillates, so it is also used in some sanding sealers to make the finish very easy to sand. See also Stearated Paper.

 References:

Hand Applied Finishes, Jeff Jewitt, Taunton Press, 1997

The New Wood Finishing Book, Michael Dresdner, Taunton Press, 1999

Pocket Ref, Thomas J. Glover, Sequoia Publishing, 1989

UAMA, the United Abrasives Manufacturers' Association, www.uama.org

Webster's New World College Dictionary, Macmillan, 1997