On 3/22/2016 9:44 AM, wai wrote:
replying to toller, wai wrote:
I guess Styrofoam absorb very little amount of water , Styrofoam boxes
we use
for preserve fish in to ice , every time after wash Styrofoam box I left
a bit
water because I pour it not entire out of water , month by month pass ,
Styrofoam box was a bit heavier than before , it store moisture in it .
sorry
my English not fluent .



Is the original poster talking Styrofoam brand blue extruded insulation
or the white foam used in sheets or molded?


Absorption depends on the quality of the manufacture. It is a cellular
material and it can absorb a tiny bit of moisture. When the box is
made, the plastic bead is blown into an aluminum mold and then heated
with steam. That causes the beads to soften and stick together. It is
then cooled and ejected. Some molders don't take the time (think cost)
to get a better box and they are the ones that eventually leak.

EPS sheets used for insulation are cut from a large billet.