On Sunday, November 15, 2015 at 10:23:42 AM UTC-5, wrote:

Where do the cross wise cracks and checking come from, based on what you have "heard"?

I've no idea. All I heard was that cracks start in the direction of the final sanding. The person that said it is very well regarded in the glider finishing world.

So does factory PU over factory gel coat delay cracking or have I just been lucky so far? I honestly don't know. I saw a badly trashed gel coat on an east coast only (with no O2 system) glider the other day and it got me wondering what the future holds for my nicely finished Polish factory PU'd wings. We both store our gliders under identical conditions.