why do old pencil erasers get hard?
hmmmmmm … too much digital stimulation?
Rubber is one of the trickiest organic compound materials to conserve over time, as direct sunlight, UV rays, and heat accelerate oxidization and breakdown.
Oxidization is basically just the rubber reacting with the atmosphere. You’ve probably seen that whitish powder on really old pencil erasers, or noticed that a hard outer skin forms on the eraser. This is oxidization. If you were to cut open an oxidized eraser, chances are that the interior is still pink and (fairly) fresh, as the exposed areas react first.
Rubber also dessicates over time, that is it dries out, loses suppleness, and cracks. I’ve seen a pair of rubber hip waders from 1916 that were dug up in France about a year ago. When they were excavated (from fairly thick, clay soil that contained little oxygen), they were in pretty good shape: flexible, slick to the touch, etc. But within a month, they had begun to harden up and crack. A temporary solution to the problem was to dampen them and freeze them and keep them in the dark, but this will only slow the process, not stop it. A more expensive treatment would be to place the hip waders in an atmosphere of pure nitrogen or other inert gas.
Ralf:
::: rimshot :::
Thank you, ladies and gentlemen, Ralf will be here all week, tip your servers…
