History[ edit ] The first recorded instance of sandpaper was in 1st-century[ citation needed ] China when crushed shells, seeds, and sand were bonded to parchment using natural gum.
Shark skin placoid scales has also been used as an abrasive and the rough scales of the living fossilCoelacanth are used for the same purpose by the natives of Comoros.
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Glass paper was manufactured in London in by John Oakeywhose company had developed new adhesive techniques and processes, enabling mass production.
Glass frit 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 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. There are many varieties of sandpaper, with variations in the paper or backing, the material used for the grit, grit size, and the bond.
Backing[ edit ] In addition to paper, backing for sandpaper includes cloth cottonpolyesterrayonPET filmand "fibre", or rubber. Cloth backing is used for sandpaper discs and belts, while mylar is used as backing for extremely fine grits.
Fibre or vulcanized 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.
Type of abrasive[ edit ] Types of abrasive materials include: The most common in modern use, with the widest variety of grits, lowest unit cost; can be used on metal i.
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 " prevents clogging and increases the useful life of the sandpaper.
The harder the grit material, the easier the sanding of surfaces like wood. The grit material for polishing granite slab must be harder than granite.
Bonds[ edit ] Different adhesives are used to bond the abrasive to the paper. Hide glue is still used, but this glue often cannot withstand the heat generated during machine sanding and is not waterproof.
Sandpapers can also be open coat, where the particles are separated from each other and the sandpaper is more flexible. This helps prevent clogging of the sandpaper. Wet and dry sandpaper is more effective used wet because clogging is reduced by particles washing away from the grinding surface.
Arguably there are also benefits due to lubrication and cooling. Sandpaper comes in a number of different shapes and sizes: May be perforated for some models of sanders.
Attachment includes pressure-sensitive adhesive PSA and " hook-and-loop " similar to Velcro. 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. Other systems used in sandpaper include the Japanese Industrial Standards Committee JISthe micron grade generally used for very fine grits.
Cheaper sandpapers sometimes use nomenclature such as "Coarse", "Medium" and "Fine", but it is unclear to what standards these names refer.2 Methodology: Identifying, Selecting, and Organizing Visualization Methods The methodology that we have applied for this paper can be separated into three steps.
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