I stole this idea from my very good friend, Paul "NoCal" Robertson. Im not sure just how he does it exactly, but I know what he uses. I never used to build the backside up on my bow grips up. After doing a few this way, Im loving it. I bought a package of 1/4 x 4 x 4 cork squares at Hobby Lobby for les than $5. I lay the cork on my bench, then lay the bow back down on the cork and trace it out. Then I use a sharp edge to cut the shape out, oversized a bit. I use TBIII wood glue to adhere the cork to the back. Once I get the cork sitting pretty I wrap it with an Ace bandage to be sure it conforms to the bow. After a day of drying I use my 4-1 rasp and a sanding block to shape it. The best part for me is the flexibility of the cork. It allows a full grip on working handle bows and that is nice as far as comfort is concerned.