When I started using bp I found I had to add 5 lb to stack to match Gordon stack , the last roll that I used a little from I was coming in heavy so I have been trying to figure out what was going on.
I built a tester today and checked several Gordon to get a kind of standard , then checked a pc of bp from the roll I’d been getting heavy on. It was some heavier , about like .003 thicker Gordon’s by my estimation. So that would be like adding .006 worth of glass ...
I also checked a pc of edge grain maple .040 lam just to see how it compared to glass.
My final theory is: between the stiffer bp and the 5 lb I’d been adding for the earlier bp is where I was getting the 10 lb over on bows .