Jesus was a carpenter

I've looked into the "R" foam....
The R stands for Regrind, the percentage they grind up and recycle.
The stuff i've checked out and done tests with, (no boards made though) is 50% regrind, so it has differing size beads throughout.
The fusion is lower, but according to the manufacturer, this is simply attributed to it's lighter weight (8kg/m3 - 10kg/m3), just as VH grade is harder to tear apart than lesser grades.
The main issue that has me avoiding it for now, it that the stuff I have access to isn't kiln dried....
As it's a packaging grade foam, they don't dry it.
All the other grades will end up in permanent applications, such as inside walls, etc, so they need to be dry.
They kiln dry it at 60 degC for a week! Something i'm not prepared to replicate at home right now.
If you want to store it somewhere dry for a few months, you could get the moisture content down.
I can make boards that flex well with the foam i'm using, and it's proven to me now, so i'm happy for the moment.
I buy my Paulownia by-the-tree-trunk, from a local plantation, so i'm lucky in that respect. It really is the most amazing wood.
I mill it myself with homemade jigs for my skill saw - works really well.It's a different one that I showed on Sways, if anyones interested. Takes some metal fabrication work to make.