Q.
Can someone tell me the difference between an "M2" and "M3" grade particleboard? This is the type of particleboard is used in custom plastic laminate millwork construction.
A.
The "M" grade is a mid-range grade, based on density (37 to 50 pounds per cubic foot). The "3" grade is about 10 to 20 percent stronger and stiffer than the "2."
Whoever is selling you the board should be able to work with you to determine which grade is appropriate for your needs.
Gene Wengert, forum moderator
Comment from contributor A:
About M2 and M3 grades; M means medium density 40-50 pounds per cubic foot, both are same density. The difference between M2 and M3: M3 board is stronger than M2 in MOR (13.7%), MOE (22%), IB (23%), and screw holding withdrawal face(9.8%) edge (11.4%). The other requirements are same for both grades.