Eraser
An eraser, also called an eraser or simply rubber, is a hand instrument or school tool whose purpose is to eliminate strokes, generally of pencil on paper, cardboard or cardboard, although they can also be used with erasable pens (for example, parchment or vellum). Already in 1770, the famous optician and manufacturer of different scientific instruments, Edward Nairne described a natural rubber to erase marks made with a pencil. It is very common to use it nowadays and it is one of the main materials in schools and offices.
Erasers, or erasers, have a rubbery consistency and come in a variety of shapes, sizes, and colors. Some contain plastic materials such as titinilium, plastic extracted from the treatment of titanium and vinyl. Some pencils have an eraser on one end. There are rubbers with plasticine extract for technical drawing, its raw material is extracted from clay which is used to make plasticine. Among the types of eraser there are: moldable rubber with a plasticine base, rubber eraser, ivory-based eraser, hard plastic eraser and the ink eraser, although not all types of ink. The term is also used to designate objects that remove marks from whiteboards and chalk boards.
Goma incorporated into a pencil.
Goma for typewriter (1960).
Goma with case.
History
Before rubber erasers, wax tablets were used to erase graphite or carbon marks from paper. Rough pieces of stone, such as sandstone or pumice, were used to remove small errors from parchment or papyrus documents written in ink. Crustless bread was used; a Tokyo student of the Meiji period (1868-1912) mentions: "Bread erasers were used instead of rubber erasers, so they were given to us without restriction on quantity. So we don't think about taking them and eating a firm part to at least slightly satisfy our hunger".
In 1770, English engineer Edward Nairne reportedly developed the first widely marketed eraser for an invention contest. Until that time, the material was known as rubber band or by its native name rubber. Nairne sold natural rubber erasers for the high price of three shillings per half-inch cube. According to Nairne, he inadvertently took a piece of rubber instead of breadcrumbs, discovered the erasing properties of rubber, and began selling rubber erasers. The invention was described by Joseph Priestley on April 15, 1770, in a footnote: "I have seen a substance excellently adapted for the purpose of cleaning from paper the mark of the black graphite pencil... It is sold by Mr. Nairne, Mathematical Instrument-Maker, opposite the Royal-Exchange ". In 1770, the word rubber was in general use for any object used for rubbing; the word was incorporated to the new material sometime between 1770 and 1778.
However, raw rubber was perishable. In 1839, Charles Goodyear discovered the vulcanization process, a method that would cure rubber and make it durable. Rubber erasers became common with the advent of vulcanization. Goodyear heated a mixture of sulfur and rubber over a stove, so that it hardened and became less sticky, without losing its elasticity.
On March 30, 1858, Hymen Lipman of Philadelphia, USA, received the first patent for attaching an eraser to the tip of a pencil. It was later invalidated because it was determined to be simply a combination of two devices rather than a completely new product.
Erasers can be freestanding blocks (block and wedge eraser) or tapered caps that can be slipped onto the end of a pencil (cap eraser). A barrel or click eraser is a pencil-shaped device, but instead of being filled with pencil lead its barrel contains a retractable cylinder of eraser material (most commonly soft vinyl). Many, but not all, wooden pencils are made with erasers attached. Novelty erasers made in shapes intended to be fun are often made of hard vinyl, which tends to smudge thick marks when used as an eraser..
Types
Pencil Eraser
Originally made of natural rubber, but now generally cheaper SBR, this type contains elements of mineral particles and an abrasive such as pumice stone with a plasticizer such as vegetable oil. They are relatively hard (to stay attached to the pencil). and are often stained pink.
Artist's Eraser
The stylized word "artist's glue" it was first used in 1903 and registered as a trademark in the United States. In 1907. This type of eraser was originally made from oils such as sulfur dichloride vulcanized corn oil, although it may now be made from natural or synthetic rubber or vinyl compounds. It is very soft but retains its shape and is not mechanically plastic, but does crumble as it is used. It is especially suitable for cleaning large areas without damaging the paper. However, they are so soft that their use is imprecise. The removed graphite is carried to the crumbs, leaving the eraser clean, but resulting in a large amount of eraser residue. This residue must be cleaned up carefully, as the eraser particles are coated with graphite and can leave new marks. Gum erasers are traditionally tan or brown in color, but some are blue.
Vinyl Erasers
High quality plasticized vinyl erasers or other "plastic" erasers, originally trademarked Mylar in the mid-century XX, are softer, non-abrasive and leave a cleaner surface than standard erasers. This is because the removed graphite does not remain in the eraser as it does in items made of rubber, but is instead absorbed into the discarded vinyl scraps. Being softer and non-abrasive, they are less likely to damage canvas or paper. Engineers prefer this type of eraser for working on technical drawings because of its delicacy on paper with less smearing in the surrounding areas. They often come blank and can be found in a variety of shapes. More recently, very low-cost erasers are made from highly plasticized vinyl compounds and made into decorative shapes.
Putty Erasers
Putty erasers have a plastic consistency and are common in most artists' standard tool kit. They can be placed in a dot to erase small areas and erase tight details, molded into a textured surface and used as a reverse stamp for texture, or used in an 'erasable' shape to create a texture. to lighten lines or shading without erasing them completely. They gradually lose their effectiveness and resistance as they become infused with particles collected from the erase and their environment. They are not suitable for erasing large areas due to their tendency to warp under vigorous erasure.
Signer Putty
Commonly sold in school supply and home improvement retailers, this soft, pliable putty comes in many colors and under many brand names. Designed to adhere posters and prints to walls without damaging the underlying wall surface, poster putty works much like traditional putty erasers, but with greater adhesion and, in some circumstances, lifting force. Poster putty does not erase but brightens the surface by directly removing particles of graphite, charcoal, or pastel from a drawing. In this sense, the poster putty does not stain or damage the work in the process. By repeatedly touching a drawing with the putty, more and more medium is released, gradually lightening the work in a controlled manner. Sign putty can be shaped into fine points or knife edges, making it ideal for small or detailed work areas. It can be rolled over a surface to create visual textures. Sign putty loses its effectiveness with use and becomes less sticky as the material grows contaminated with debris and oils from the user's skin.
Electric Erasers
The electric eraser was invented in 1932 by Arthur Dremel of Racine, Wisconsin, USA. It used a replaceable cylinder of drafting material held by a chuck driven on a motor shaft. The speed of rotation allowed less pressure to be used, which minimized damage to the paper. Originally standard pencil eraser was used, later replaced by higher performance vinyl. Dremel went on to develop a complete line of portable rotary power tools.
Fiberglass Erasers
A fiberglass eraser, a bundle of very fine glass fibers, can be used for erasing and other tasks that require abrasion. The eraser is usually a pen-shaped device with a replaceable insert filled with glass fibers, which wear out with use. The fibers are very hard; In addition to removing pen and pencil marks, these erasers are used to clean traces on electronic circuit boards for easier soldering, rust removal, and many other applications. As an example of unusual use, a fiberglass eraser was used to prepare a pterosaur fossil embedded in very hard and massive limestone. Because fiberglass erasers spew fiberglass dust when are used, care should be taken during and after use to avoid accidental contamination with this abrasive powder on sensitive areas of the body, especially the eyes.
Others
Felt blackboard erasers or blackboard dusters are used to erase chalk marks on a blackboard. Chalk writing leaves light-colored particles that adhere weakly to a dark surface (eg, white on black or yellow on green); it can be rubbed with a soft material, such as a cloth. Whiteboard erasers are made from a block of plastic or wood, much larger than a pen or pencil eraser, with a layer of felt on one side. The block is held in the hand and the felt is rubbed against the writing, which is easily erased. Chalk dust is released, some of which sticks to the eraser until it is cleaned off, usually by tapping it against a hard surface.
Various types of erasers, depending on the board and the type of ink used, are used to erase a whiteboard.
The special erasers supplied with some permanent pens and markers are intended solely for erasing ink from the writing instrument for which they are made; sometimes this is done by making the ink adhere more strongly to the material of an eraser than to the surface to which it was applied.
Liquid correction and correction tape offer an alternative to the eraser to remove ink.
The computer allows you to erase without leaving a trace; but the eraser icon is used in graphic software to indicate the function that restores, more or less gradually, the color of the background.