The peel ply material is generally used to allow the builder to have a "re-bondable" surface which requires no additional preparation once the peel ply is removed. That is very important, however, the peel ply serves other important functions as well. When applied over the wet lay-ups, you have a surface that will allow you to squeegee trapped air out without allowing the glass layers to move and shift around .  When the resin/fiberglass layup is cured and the peel ply is removed, the surface will be free of harmful sharp edges and spurs.

The resin surface normally will not totally cure when exposed to air which acts as an inhibitor. The peel ply  application will seal the surface and allow the resin to thoroughly cure. This complete curing of the resin surface is very important.   Later when sanding or grinding the surface, the "sticky stuff" will not be there to load up your sandpaper with uncured resin.

Note: If you do have the sticky surface because the resin was applied without peel ply, wash the surface with a clean rag soaked with acetone. The acetone will remove the uncured resin and allow load free sanding.

  Peel Ply fabrics may be used to build large composite structures or to facilitate small repairs where a clean, textured surface is desired for additional bonding and finishing operations. A Peel Ply layer also provides pressure to the GRP composite structure during fabrication and cure allowing gas to escape thereby eliminating blisters. Where Peel Ply fabric is used, the laminate will be smoother and will achieve a higher fiber to resin content thus increasing strength. Without Peel Ply, production of vacuum-formed laminates, especially composites made with epoxy/carbon/Kevlar, is hardly possible. Furthermore, excellent non-skid surfaces can be obtained.

peel ply:
1.blade separation and Cabin cover;
2. free of oil and other release agents;
3.white color with red stripes