I am at the stage of spraying the poly spray , searched this forum, watched many videos and read the Stits Poly Fiber manual ( many times ) . My concerns that I learned were that as few as 2 swipes across a hard surface , tubing, top of a rib, or stitch with 400 grit wet sanding can cut right through the fabric and then it MUST be repaired. Today I cautiously started out on the elevator, I just broke through into the poly brush, stopped, and said there must be a better way to scuff this surface for the 3rd spray coat of Poly spray to be laid down as the manual suggests. I called Waldow at " consolidated " and talked to him . He said that using red scotch brite lightly on all the surfaces will give the next applied Silver or paint its needed tooth bonding surface. I cannot express how nice this method is. A few strokes several times over the surface is easy to see, multiple strokes over the same area, either on tubing , stitches, ribs, or tapes I NEVER had a reddish ( poly brush ) color show up, with a resulting nice even scuff of the surface area. I want to pass this along to anyone ready to paint their project, especially after months and months of work and only then to have the misfortune that I have witnessed others having with unwanted repair (s) wet sanding this poly spray. This red Scotch brite is the ticket, right from Mr. Waldow himself ! Carry on with confidence, Billy