What is an Eraser made of?
What is an Eraser made of?
Either natural rubber with fine abrasive and oil, or plasticised PVC — two different ways of lifting graphite.
Erasing is two processes at once: the eraser is stickier than the paper, so loose graphite transfers onto it, and the abrasive removes the thin layer of fibre that graphite has been pressed into. That is why a hard eraser on thin paper takes the paper with it, and why erasing ink means abrading the surface until the sizing is gone and anything written afterwards feathers. Rubber got its English name from this job — Joseph Priestley noted in 1770 that the new elastic gum from South America was good for "rubbing out" pencil marks, and the substance has been called rubber ever since. Plastic erasers are not rubber at all; they are soft PVC, which is also why they can go hard and yellow with age as the plasticiser migrates out.
Component by component
| Part | Material | Why that material |
|---|---|---|
| body (rubber type) | natural rubber, vulcanised, with vegetable oil and sulfur | Rubber is tacky enough to grab loose graphite and elastic enough to crumble away rather than polish the paper. |
| body (plastic type) | polyvinyl chloride with a high loading of plasticiser | A soft vinyl erases with almost no pressure and leaves clean crumbs, which is why draughtsmen and artists prefer it. |
| abrasive filler | finely ground pumice or feldspar | Graphite that has been pressed into the paper fibres has to be sanded off; without filler the eraser only lifts the surface layer. |
| kneaded eraser | unvulcanised rubber, sticky and mouldable | It lifts graphite purely by adhesion with no abrasion at all, so it lightens charcoal without damaging the paper surface. |
Other stationery and paper objects
- Pencil Graphite mixed with clay and fired, glued inside two grooved halves of softwood. No lead, ever.
- Paper Cellulose fibres from wood pulp, plus up to a third mineral filler, sizing and brightener.
- Ballpoint pen A tungsten carbide ball a millimetre across, rolling in a brass socket, fed by thick oil-based ink.
- Glitter Aluminium-coated polyester film, colour-coated and chopped into fragments — by definition a microplastic.
- Crayon Paraffin wax with pigment stirred in, poured hot into a mould and cooled. Almost nothing else.
- Cardboard Two flat kraft paper liners glued either side of a fluted paper medium — the flutes do all the work.
- Blackboard chalk Mostly calcium sulfate — plaster of Paris — rather than the calcium carbonate the name suggests.
- Playing card Two sheets of paper laminated around a black glue core, then coated in plastic — or solid PVC.
- Postage stamp Coated paper with phosphor bands, printed in security inks, on either water-activated gum or a self-adhesive.
Common questions
- What is an Eraser made of?
- Either natural rubber with fine abrasive and oil, or plasticised PVC — two different ways of lifting graphite.
- What is the body (rubber type) of an Eraser made of?
- Natural rubber, vulcanised, with vegetable oil and sulfur. Rubber is tacky enough to grab loose graphite and elastic enough to crumble away rather than polish the paper.
- What is the body (plastic type) of an Eraser made of?
- Polyvinyl chloride with a high loading of plasticiser. A soft vinyl erases with almost no pressure and leaves clean crumbs, which is why draughtsmen and artists prefer it.
Related pages
- Pencil Graphite mixed with clay and fired, glued inside two grooved halves of softwood. No lead, ever.
- Paper Cellulose fibres from wood pulp, plus up to a third mineral filler, sizing and brightener.
- Ballpoint pen A tungsten carbide ball a millimetre across, rolling in a brass socket, fed by thick oil-based ink.
- Glitter Aluminium-coated polyester film, colour-coated and chopped into fragments — by definition a microplastic.
- Crayon Paraffin wax with pigment stirred in, poured hot into a mould and cooled. Almost nothing else.
- Cardboard Two flat kraft paper liners glued either side of a fluted paper medium — the flutes do all the work.
- Blackboard chalk Mostly calcium sulfate — plaster of Paris — rather than the calcium carbonate the name suggests.
- Playing card Two sheets of paper laminated around a black glue core, then coated in plastic — or solid PVC.
- Tennis ball Sport and games
- Banknote Around the house
- Golf ball Sport and games
- Glass Building materials
- Soccer ball Sport and games
- Marshmallow Food and drink
Sources
- Typical range compiled from manufacturer specifications — At One Place