If the school supply list includes pencils, you can expect it to also include a request for one or more erasers. One of the advantages of writing with a pencil instead of a pen is that you can easily remove the written text using an eraser.
Erasers come in a variety of shapes, sizes, and colors. Before stocking up on erasers for school, ideally, test the eraser to find out if it is good or not. There are quite a few novelty erasers out there in the shops that look (and even smell!) great but aren’t very good at actually erasing. You don’t want to end up with a semester worth of erasers that damage the paper, smear the text or leave colored smudges in their path.
Examples of eraser types
Pencil erasers made from gum or SBR
These erasers are used to erase pencil writing, and they are very common in schools. Originally, they were made from natural rubber, but today SBR is much more common since it is cheaper. In some English-speaking countries, pencil erasers are simply known as rubbers, a name harking back to the time when natural rubber erasers were common.
SBR is a synthetic product developed as an alternative to natural rubber. In addition to SBR, an eraser will typically contain mineral fillers and an abrasive such as pumice with a plasticizer such as vegetable oil.
Trivia: SBR was invented in Germany in 1929 by Walter Bock, but didn’t really catch on until World War II. During the war, the U.S. Government began manufacturing huge amounts of SBR since the Allied nations could no longer get natural rubber from plantations in Southeast Asian countries occupied by Japanese forces.
Pencil erasers made from vinyl
Vinyl erasers are also common in schools, and they are also favored by many professionals who use pencils in their work. Compared to erasers made from gum or SBR, vinyl erasers are softer and less abrasive. They erase cleaner and are less likely to damage the paper or smear surrounding areas.
With a gum/SBR eraser, quite a lot of graphite from the erased pencil markings gets stuck on the surface of the eraser, making it dirty. A vinyl eraser, on the other hand, will continuously shed small vinyl scraps while in use. The graphite is found on these scraps, and not on the remaining eraser. Over time, the vinyl eraser will, of course, become smaller and smaller due to this process.
The classic color for vinyl erasers is white, but today this type of eraser is available in many other colors as well.
Artist’s gum eraser
Launched in the early 1900s, this type of eraser was made from oil (e.g. corn oil) vulcanized with sulfur dichloride. Today, you can also buy artist’s gum erasers made from natural rubber, synthetic rubber or vinyl.
What makes this type of eraser special is that it is extremely soft (yet retains its shape) and crumbles while being used. It is well suited for erasing markings from large areas without injuring the paper. It is not suitable for erasing small areas since its softness makes it difficult to use in a precise manner.
The removed graphite will end up on the crumbles that are leaving the eraser, so the remaining eraser will stay clean.
You can expect a lot of crumbles on your paper when using an artist’s gum eraser. Shake or brush it away with care to keep the graphite from making new marks on the paper.
Artist’s gum erasers are also known as art gum erasers and artgum. Their traditional color is tan or brown.
A fiberglass eraser consists of a bundle of very fine glass fibers. It erases by being very abrasive.
This type of eraser is typically contained within a pen-shaped casing. The casing is filled with replaceable inserts that hold the actual bundles of glass fibers.
Kneaded erasers are typically used by artists and are unusual in schools, although some schools use them for certain art classes.
Kneaded erasers have a plastic consistency and the user can mold them into various shapes, allowing for very precise erasing. You can, for instance, form a sharp point and use it to erase a very small detail in a pencil sketch. Some artists mold a piece of eraser into a textured surface that can then be used as a kind of “reverse stamp” to form patterns on the paper by removing pencil markings. Kneaded erasers are also great for slightly, but not fully, removing pencil markings.
As the kneaded eraser picks up graphite, charcoal, carbon, pastel, or other products during erasing, it will gradually become infused with these contaminants and become less and less useful until it needs to be discarded. It does not shed contaminated parts and does not become smaller and smaller with use. If not discarded in time, it starts leaving marks on the paper.
Kneaded erasers are very soft and tend to easily lose their shape if pressure is applied to them. Vigorous erasing of larger areas will not work out well with this type of eraser.
If the kneaded eraser gets warm, it might smear.
Traditionally, kneaded erasers were gray or white. Today, they are available in many other colors as well.
Poster putty is sometimes used as a substitute for the kneaded eraser. The intended use for poster putty is to adhere posters and similar to walls without damaging neither the wall nor the poster. When shopping for school supplies, it is usually much easier to find a shop selling poster putty than one selling kneaded erasers. To buy a kneaded eraser, you might have to search out a specialized art supply store, while poster putty is found in a much wider range of retail establishments.
While there are many erasers capable of removing pencil markings, removing ink from the paper is considerably more difficult and require a special ink eraser. Ink erasers are not common in schools and virtually never included in school supply lists.
Mechanical ink eraser work by scraping ink off the surface of the paper. They can, for instance, feature a metal scraper, fiberglass or a gum eraser with additional abrasives (e.g. sand). Naturally, they also cause some damage to the paper if the paper has absorbed the ink.
Chemical ink erasers, also known as eradicators, contain a substance that reacts with the ink, removing the pigmentation and rendering the ink more or less invisible. You need to get an eraser with a substance that works for your particular ink type. The chemical ink eraser is a more modern invention than the mechanical ones; it was created by Pelikan in the 1930s. Most chemical ink eraser on the market are adapted for royal blue ink only and work by letting sulfite or hydroxide ions bind to carbon atoms in the dye. The blue pigmentation becomes invisible but can be brought back again with aldehydes.