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Sandy Finesse
When you look at a piece of wooden furniture, the first thing that attracts you is its smooth finishing, right? And when you look at the walls of your house or school or office, only an even texture pleases you. But, do you know that this smoothness comes from something coarse?
This coarse material is known as sandpaper. It is a type of coated abrasive. Abrasives are materials used to shape or finish an object by rubbing. They wear away part of the material. Coated abrasives are the ones pasted on the surface of flexible or semi-flexible backings (platform), like paper and cloth.
Sandpaper is used to remove small amounts of material from surfaces of paintings and wood finishings to make them smoother. They are also used to remove layers of old paint, and sometimes to make a surface rough. They are mostly used for furniture making, in automotive industries, and in the world of art and craft.
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The making
 ‘Make coat’, the first layer of adhesive, is applied to one side of the backing material.
The backing is passed, adhesive side down, over a pan of abrasives that has been given an electric charge opposite to the backing (electrostatically charged). The opposite charge causes the abrasives to stick evenly to the backing.
The roll is dried and a second layer of adhesive, called size coat, is applied.
The roll is dried again and cured under carefully controlled temperature and humidity conditions.
The finished product is wound on a large spool and shipped to the companies that convert it into sanding belts or other items after ‘flexing’ — bending it to break the stiff layer of adhesive bond. |
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COMMONLY USED ABRASIVE MATERIALS
Garnet — used in woodworking
Emery — used to abrade or polish metal
Aluminium oxide — used on metal or wood
Silicon carbide — common in wet applications
Alumina-zirconia (aluminium oxide-zirconium oxide alloy) — used for machine grinding applications
Chromium oxide — used in extremely fine micron grit* (micrometre level) papers
Glass – glass particles were once widely used
*Grit size refers to the size of the particles of abrading materials embedded in the sandpaper. The lesser the grit size, the coarser the sandpaper, and vice-e-versa.
Rubbing facts
Using sandpaper may be a little risky. Why?
Sanding waste may contain heavy metals, which might get washed away to gutters, streets, or leach underground.
The dust particles in the air may be harmful for the workers, and cause respiratory diseases.
So, it’s better to take steps like:
Sanding in a particular area to control waste
Cleaning up after each task
Wearing personal protective equipment (PPE) like coveralls and gloves
Separating hazardous sanding waste from other wastes
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