Is 4001 Synered from plastic beads and 2001 extruded with a more closed surface?
How much will I notice it for everyday use? Basically, I have some sheets of 2001 donated for free. I try to build out of quality materials since I am putting my time in on the project.
4001 is a higher molecular weight grade of sintered base than 2001. It is more durable, should hold wax better, and be a little easier to finish. If finished properly, 4001 should run slightly faster that 2001...but more will depend on the finishing job of the manufacturer.