EPS is made up of
very thin-walled beads, surrounded by open channels (as delineated on the
assorted scum and salts taken on together with a gulp of water, allowed to
stew for a couple of days).
As water enters the core through an injury, or a
forgotten vent plug, it spreads throughout the board via these channels. The
more water entered and the warmer the board, the faster the spread.
As the water spreads, it brings with it hygroscopic salts, which
make removal difficult. It is therefore beneficial to extract the water
BEFORE it has a chance to spread. Hours can make a difference on a hot day!
The liquid water in these channels, exposed to
elevated temperatures, will turn to vapor. The vapor
molecules, being dramatically smaller than the liquid water molecules, are able
to permeate the cell membranes.
Once inside the cells, it is an utter pain to
extract the water again. Permanent weight gain, as well as permanent propensity to
suffer heat-related damage will be the result.
from this - virgin EPS
to this - damp EPS