I see an interest in the thread, and I want to thank you all who participated. But... how many of us actually know what is the sandpaper made of and how to choose the correct one for a given job? Stay tuned and you will have a chance to learn, thanks to WIKI!!
Sandpaper, also known as
glasspaper, is a heavy
paper with abrasive material bonded to its surface. Sandpaper is part of the "coated abrasives" family of abrasive products. It is used to remove small amounts of material from surfaces, either to make them smoother (painting and wood finishing), to remove a layer of material (e.g. old paint), or sometimes to make the surface rougher (e.g. as a preparation to gluing).
The first recorded instance of sandpaper was in 13th-century China when crushed shells, seeds, and sand were bonded to parchment using natural gum. Sharkskin was also used as a sandpaper. The rough scales of the living fossil Coelacanth are used by the natives of Comoros as sandpaper. Boiled and dried, the rough horsetail is used in Japan as a traditional polishing material, finer than sandpaper.
Sandpaper was originally known as
glass paper, as it used particles of glass. Glass frit has sharp-edged particles and cuts well, sand grains are smoothed down and do not work well like sandpaper made from glass. Cheap counterfeit sandpaper has long been passed off as true glass paper; Stalker and Parker cautioned against it in the 17th century. Glass paper was manufactured by John Oakey's company in London by 1833, who had developed new adhesive techniques and processes, enabling mass production. A process for making sandpaper was patented in the United States on June 14, 1834, by Isaac Fischer, Jr., of Springfield, Vermont.
In 1921, 3M invented a sandpaper with a waterproof backing, known as
Wetordry. 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 automotive paint refinishing.
Material Materials used for the abrading particles are:
- Flint: no longer commonly used
- Garnet: commonly used in woodworking
- Emery: commonly used to abrade or polish metal
- Aluminum oxide: perhaps most common in the widest variety of grits; can be used on metal (i.e. body shops) or wood
- Silicon carbide: available in very coarse grits all the way through to microgrids, common in wet applications
- Alumina-zirconia: (an aluminium oxide–zirconium oxide alloy), used for machine grinding applications
- Chromium oxide: used in extremely fine micron grit (micrometer level) papers
- Ceramic aluminum oxide: 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" 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. Later abrading surfaces include long-life stainless steel sanding discs. 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. The wet and dry sandpaper is best used when wet.
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