Thanks, I think this was my "lottery" group and yes, I am starting to damage feathers, but I'm still not courageous enough to shoot to the outside of the target - lol.
Yes, it is industrial grade polyurethane that a friend experimented for me. It is 8" thick and 2 psi (I think). It is not his 3 psi foam, but he layers 2" at a time allowing them to dry. Because of this, I have a 3 x 3 rubber mat bonded with the foam on the back side as a back stop. The arrows are starting to go through.
What is nice about this is, when it gets bad, I'll cut out the middle section and have him spray a new section for maybe 10 bucks or so.
He thinks the 3 psi will be more durable. It is what they use to seal a new house to the foundation.
Tim