I got some fake copperhead cloth from 3-Rivers archery.I was wanting to put them on an osage self-bow.The back has spray poly on it.My question is ,do I need to sand all the poly off or just ruff it up,and has anyone else used this?Is it any good?Any good tip on applying?Any thoughts would be appreciated.

I have used the 'faux' snake skins on several bows, once to cover that dreadful streaky clear glass we were getting not long ago. Being on glass I slightly scuffed the glass with 180 grit , then put a layer of titebond 3 on as sizing. then next day quickly wet the 'skins' and applied titebond to the underside then applied to bow, smoothing out all bubbles and creases as I went. left for couple days and then carefully trimmed edged with sharp boxcutter.

I've used the faux copperhead skin on an osage bow and did not like how it looked.  I dyed the titebond with brown water based leather dye till I liked how they looked.  I did small sections on a scrap piece of osage till I liked how it looked by adding more dye to each test piece.  As far as application I would sand most of the finish off, IMO.