upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine)). Sandpaper and glasspaper are names used for a type of

coated abrasive upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine)). Sandpaper and glasspaper are names used for a type of coated abrasive that consists of sheets of paper or cloth with abrasive material glued to ...

that consists of sheets of

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distributed ...

or cloth with abrasive material glued to one face. There are many varieties of sandpaper, with variations in the paper or backing, the material used for the grit, grit size, and the bond. In the modern manufacture of these products, sand and glass have been replaced by other abrasives such as aluminium oxide or silicon carbide. It is common to use the name of the abrasive when describing the paper, e.g. "aluminium oxide paper", or "silicon carbide paper". Sandpaper is produced in a range of grit sizes and is used to remove material from surfaces, whether to make them smoother (for example, in

painting Painting is the practice of applying paint, pigment, color or other medium to a solid surface (called the "matrix" or "support"). The medium is commonly applied to the base with a brush, but other implements, such as knives, sponges, and ...

and wood finishing), to remove a layer of material (such as old

paint Paint is any pigmented liquid, liquefiable, or solid mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture. Paint can be made in many ...

), or sometimes to make the surface rougher (for example, as a preparation for gluing). The grit size of sandpaper is usually stated as a number that is inversely related to the particle size. A small number such as 20 or 40 indicates a coarse grit, while a large number such as 1500 indicates a fine grit.

History

The first recorded instance of sandpaper was in 13th-century

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

when crushed shells, seeds, and

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...

were bonded to parchment using

natural gum Natural gums are polysaccharides of natural origin, capable of causing a large increase in a solution's viscosity, even at small concentrations. They are mostly botanical gums, found in the woody elements of plants or in seed coatings. Human u ...

Shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimo ...

skin (

placoid scales A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as we ...

) has also been used as an abrasive and the rough scales of the

living fossil A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossi ...

, Coelacanth are used for the same purpose by the natives of

Comoros The Comoros,, ' officially the Union of the Comoros,; ar, الاتحاد القمري ' is an independent country made up of three islands in southeastern Africa, located at the northern end of the Mozambique Channel in the Indian Ocean. It ...

. Boiled and dried, the rough horsetail plant is used in Japan as a traditional polishing material, finer than sandpaper. Glass paper was manufactured in

London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...

in 1833 by John Oakey, whose company had developed new adhesive techniques and processes, enabling mass production. Glass

frit A frit is a ceramic composition that has been fused, quenched, and granulated. Frits form an important part of the batches used in compounding enamels and ceramic glazes; the purpose of this pre-fusion is to render any soluble and/or toxic compo ...

has sharp-edged particles and cuts well whereas sand grains are smoothed down and do not work well as an abrasive. Cheap sandpaper was often passed off as glass paper; Stalker and Parker cautioned against it in ''A Treatise of Japaning and Varnishing'' published in 1688. In 1921, 3M invented a sandpaper with silicon carbide grit and a waterproof adhesive and backing, known as ''Wet and dry''. This allowed use with water, which would serve as a lubricant to carry away particles that would otherwise clog the grit. Its first application was in automotive paint refinishing.

Coated abrasive

A coated abrasive is an abrasive grain bonded to a flexible

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...

using

adhesive Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advant ...

s. Common substrates are

, cloth, vulcanized fiber, and

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

films and come in grit sizes range from very coarse (~2 mm) to ultrafine (sub

micrometre The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

). The

international standard international standard is a technical standard developed by one or more international standards organizations. International standards are available for consideration and use worldwide. The most prominent such organization is the International Or ...

for coated abrasives is ISO 6344. Sandpaper and emery cloth are coated abrasives for hand use, usually non-precision. Other coated abrasive forms include sanding cords, pads, belts, and discs. Variants are available for use by hand or as components for

power tool A power tool is a tool that is actuated by an additional power source and mechanism other than the solely manual labor used with hand tools. The most common types of power tools use electric motors. Internal combustion engines and compressed ...

s such as sanders,

die grinder Die grinders and rotary tools are handheld power tools used for grinding, sanding, honing, polishing, or machining material (typically metal, but also plastic or wood). All such tools are conceptually similar, with no bright dividing line betwe ...

s and

belt sander A belt sander or strip sander is a sander used in shaping and finishing wood and other materials. It consists of an electric motor that turns a pair of drums on which a continuous loop of sandpaper is mounted. Belt sanders may be handheld and mo ...

Mounting systems

A quick change system is commonly used with disc type coated abrasives. A plastic or metal hub is bonded to one of the faces, which is threaded. This then mates directly to the sander/ grinder or to a mandrel that can be mounted in a sander, grinder, or

drill A drill is a tool used for making round holes or driving fasteners. It is fitted with a bit, either a drill or driverchuck. Hand-operated types are dramatically decreasing in popularity and cordless battery-powered ones proliferating due to ...

. The advantage is that the disc can be quickly replaced when needed. Quick change discs range in sizes from to no upper limit.

Backing

320 grit silicon carbide sandpaper, with close-up view In addition to paper, backing for sandpaper includes cloth (

cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor perce ...

polyester Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natural ...

rayon Rayon is a semi-synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products. It has the same molecular structure as cellulose. It is also called viscose. Many types and grades of viscose f ...

), PET film, "fibre", and rubber. Cloth backing is used for sandpaper discs and belts, while mylar is used as backing for extremely fine grits. Fibre or

vulcanized Vulcanization (British: Vulcanisation) is a range of processes for hardening rubbers. The term originally referred exclusively to the treatment of natural rubber with sulfur, which remains the most common practice. It has also grown to includ ...

fibre is a strong backing material consisting of many layers of polymer impregnated paper. The weight of the backing is usually designated by a letter. For paper backings, the weight ratings range from "A" to "F", with A designating the lightest and F the heaviest. Letter nomenclature follows a different system for cloth backings, with the weight of the backing rated J, X, Y, T, and M, from lightest to heaviest. A flexible backing allows sandpaper to follow irregular contours of a workpiece; relatively inflexible backing is optimal for regular rounded or flat surfaces. Sandpaper backings may be glued to the paper or form a separate support structure for moving sandpaper, such as used in sanding belts and discs. Stronger paper or backing increases the ease of sanding wood. The harder the backing material, the faster the sanding, the faster the wear of the paper and the rougher the sanded surface.

Abrasives

Types of abrasive materials include: *

Glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) of ...

: No longer commonly used. *

Flint Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Flint was widely used historically to make stone tools and start fir ...

: No longer commonly used. *

Garnet Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different s ...

: Commonly used in

woodworking Woodworking is the skill of making items from wood, and includes cabinet making (cabinetry and furniture), wood carving, woodworking joints, joinery, carpentry, and woodturning. History Along with Rock (geology), stone, clay and animal parts, ...

. * Emery: Commonly used to abrade or polish metals. * Aluminium oxide: The most common in modern use, with the widest variety of grits, lowest unit cost; can be used on metal (i.e. body shops) or wood. * Silicon carbide: Available in very coarse grits all the way through to microgrits, common in wet applications. * Alumina-zirconia: (An aluminium oxide– zirconium oxide alloy), used for machine grinding applications. * Chromium(III) oxide: Used in extremely fine micron grit (

level) papers. *

Diamond Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the Chemical stability, chemically stable form of car ...

: Used for finishing and polishing hard metals, ceramics and glass. *

Ceramic aluminum oxide A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...

: Used in high pressure applications, used in both coated abrasives, as well as in bonded abrasives. Sandpaper may be " stearated" where a dry lubricant is loaded to the abrasive. Stearated papers are useful in sanding coats of finish and paint as the stearate "

soap Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are use ...

" prevents clogging and increases the useful life of the sandpaper. The harder the grit material, the easier the sanding of harder surfaces like hardwoods such as

hickory Hickory is a common name for trees composing the genus ''Carya'', which includes around 18 species. Five or six species are native to China, Indochina, and India (Assam), as many as twelve are native to the United States, four are found in Mexi ...

pecan The pecan (''Carya illinoinensis'') is a species of hickory native to the southern United States and northern Mexico in the region of the Mississippi River. The tree is cultivated for its seed in the southern United States, primarily in Georgia, ...

, or wenge. The grit material for polishing

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

must be harder than granite.

Bonds

Different adhesives are used to bond the abrasive to the paper.

Hide glue Animal glue is an adhesive that is created by prolonged boiling of animal connective tissue in a process called rendering. In addition to being used as an adhesive it is used for coating and sizing, in decorative composition ornaments, and as a ...

is still used, but this glue often cannot withstand the heat generated during machine sanding and is not waterproof. Waterproof sandpapers or wet/dry sandpapers use a resin bond and a waterproof backing. Sandpaper can be either ''closed coat'' or ''open coat''. Approximately 90% to 95% of the surface is covered with abrasive grains with a closed coat. Closed coat sandpaper is good for hand sanding or working with harder materials. In comparison, 50% to 70% of the surface is covered with abrasive grains with open coat sandpaper. The separation between particles makes the sandpaper more flexible, which prevents the sandpaper from clogging. However, the gaps in grit coverage limits the sandpaper's ability to perform even polishing jobs. Open coat sandpaper is better for softer materials. Wet and dry sandpaper is more effective used wet because clogging is reduced by particles washing away from the grinding surface.

Shapes

Sandpaper comes in a number of different shapes and sizes: * sheet: usually , but other sizes may be available * belt: usually cloth backed, comes in different sizes to fit different

s. * disk: made to fit different models of disc and random orbit sanders. May be perforated for some models of sanders. Attachment includes pressure-sensitive adhesive (PSA) and "

hook-and-loop Hook-and-loop fasteners, hook-and-pile fasteners or touch fasteners (often referred to by the genericized trademark velcro, due to the prominence of the Velcro Brand) consist of two components: typically, two lineal fabric strips (or, alternat ...

" (similar to Velcro). * rolls: known as "shag rolls" by many contractors * sponge: for tight places

Grit sizes

Grit size refers to the size of the particles of abrading materials embedded in the sandpaper. These measurements are determined by the amount of the abrasive material that can fit through a square inch filter. Several standards have been established for grit size. These standards establish not only the average grit size, but also the allowable variation from the average. The two most common are the United States CAMI (Coated Abrasive Manufacturers Institute, now part of the Unified Abrasives Manufacturer's Association) and the European FEPA (Federation of European Producers of Abrasives) "P" grade. The FEPA system is the same as the ISO 6344 standard. Other systems used in sandpaper include the

Japanese Industrial Standards Committee The is a standards organization and is the International Organization for Standardization (ISO) member body for Japan. It is also a member of the International Electrotechnical Commission. The committee consists of a Council under the Ministry o ...

(JIS), the micron grade (generally used for very fine grits). Cheaper sandpapers may sometimes only use descriptive nomenclature such as "coarse", "medium" and "fine" without referring to any standard. The following table, compiled from the references at the bottom, compares the CAMI and "P" designations with the average grit size in micrometres (µm).

Emery cloth

Emery cloth is a type of

that has emery glued to a cloth backing. It is used for hand metalworking. It may be sold in sheets or in narrow rolls, typically 25 or 50 mm wide, often described as "emery tape". The cloth backing makes emery cloth stronger in tension than paper, but still allows a sheet to be conveniently torn to size. Emery (largely displaced by improved products such as aluminum oxide and silicon carbide) is used for scrubbing highly abraded and rough surfaces to a smooth and shiny finish, notably in watchmaking

Emery paper Emery paper is a type of abrasive paper or sandpaper, that can be used to abrade (remove material from) surfaces or mechanically finish a surface. Operations include deburring, polishing Polishing is the process of creating a smooth and sh ...

, more commonly seen, has a paper backing and is usually a finer grit. Emery was considered a suitable abrasive for fitting work and the final adjustment of steel parts for a perfect fit. It had the advantage that, unlike harder abrasives, it was not considered to embed abrasive traces in the polished components afterwards. Emery was also used for cleaning, as a means of removing rust from polished steel components. Both emery cloth and paper are still sold in hardware and

do it yourself "Do it yourself" ("DIY") is the method of building, modifying, or repairing things by oneself without the direct aid of professionals or certified experts. Academic research has described DIY as behaviors where "individuals use raw and semi ...

stores, but have been largely supplanted by the increased use of machine grinding to precision size, which has minimized or eliminated the need for hand-fitting; the widespread availability of powered hand tools employing sanding and grinding accessories such as

flapwheel A flapwheel and the related flap disk is an abrasive disk, used for metal finishing. Unlike the simpler flat disks, made from a circular flat sheet of a coated abrasive, a flapwheel is made of multiple overlapping small pieces or 'flaps', bonded t ...

s; and a shift to other forms of abrasive, such as aluminum oxide, aluminium zirconia and silicon carbide.

Grades

Emery is rated on the average grit size, glued to the backing. Common sizes are, from coarse to fine: 40, 46, 54, 60, 70, 80, 90, 100, 120, 180, 220, 320, F, and FF. A 46 or 54 grade cloth is used on roughly filed work, while 220 to 320 grit cloth will give a good

polish Polish may refer to: * Anything from or related to Poland, a country in Europe * Polish language * Poles, people from Poland or of Polish descent * Polish chicken *Polish brothers (Mark Polish and Michael Polish, born 1970), American twin screenwr ...

Similar products

''Sandpaper'' tends to be a generic term for several simiar abrasive papers and cloths

Wet & Dry

Abrasive papers and cloths with a waterproof backing allow the use of a lubricant, typically water, which can both decapitate rough surfaces when used dry and produce a semi-polished satin type finish when wet. Super-fine grades can produce a "key" adhesion surface appropriate for spray painting in critical decorative applications such as automotive bodywork repairThe polishing shop (UK): Abrasive Wet and Dry Paper
/ref>

Crocus

a very soft abrasive usually ultra-fine

Jeweler's rouge Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturally a ...

for fine hand-polishing of hard surfaces that require the smoothest finish possible.

References

External links

Federation of European Producers of Abrasives

{{Metalworking navbox, machopen Abrasives Chinese inventions Paper products Surface finishing