There are different schools of thought when it comes to this and I thought I'd put it to the group. I've heard people say that if peel ply is used there is no need to key the area up before laminating/painting/glueing. I've also heard the opposite that even if you have peel plyed once the laminate is no longer 'green' use must key up before adhering to it. 

I will always abrade after using peel ply then a bit of acetone to clean up prior to bonding

Keying up is a lot quicker on a peel ply finish as half the roughness is already there so there is no harm in further keying to ensure the finish is even. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

I understand it's along quicker but is it necessary. Was peel ply designed to completely irradiate the need for keying up a surface or to minimalise it. I understand on smaller components this isn't as much of an issue because it doesn't take as much effort to key and clean the surface, however if laying up a 13m hull mould keying up, hoovering and acetone cleaning the surface is a much bigger task. 

Peel ply is designed primarily as a removable pourous barrier between the laminate and other part of the bagging stack.  Providing a good surface for secondary bonding is a secondary function and in essence a byproduct of the peel ply's surface texture. In most cases, the peel ply finish will be fine, however a good key of the surface may well give slightly better results.  Also be aware that there are some "release-coated" peel ply's on the market which are coated in release agents to aid removal.  These almost always leave a trace/layer of release agent on the finished part and will need a thorough key and clean to ensure all traces are removed to get a good bond.

If in doubt, we always recommend full surface preparation prior to bonding. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Thank you for the clarification. Very useful information.