is the # = lbs??

The numbers represent pounds per cubic foot. So, #2 EPS would be 2 pounds per cubic foot of styrofoam. The higher the number, the heavier and more dense.

#2 has twice the material fused into the same size as #1. Like said above, it makes a more dense material. #2-2.5 is pretty nice to work with. #3 or #4 will be pretty hard/dense. #1 the home depot sheet stuff is a waste of time. You also have to becareful of the bead size too, that can make a big difference with tear out.

The numbers given for EPS weight are all pre-molded weight and are not the exact weight you would get from a blank cut from a block as the density of a block is greater at the outside and lower towards the center of the block. This could vary the blank by a half-pound or so. Molded blanks such as the Marko product is way more exact and should be within a 1/10 of a pound. A heavier density blank also has a smaller bead size even when the same “type” of bead is used. Block foam insulation is made out of “B” bead or even “A” bead which are quite large and will make larger pukas (tear-outs) which will need to be filled before glassing.

If you are looking at EPS as a blank material, 2 lb. or heavier will make the best material and “C” size bead the best to shape.

13yrs in the EPS biz/backyarder for 30+

When the character # follows a number it is called a Pound Sign". It is read as pound or pounds (lb. or lbs.). In your example 2# is read two pounds.

When # precedes a number it is called a Number Sign. For example: #2 is read as number two.

On you phone is it called the Pound Sign.