How can I seal an XPS Skimboard blank to glass it with Poly?

I keep forgetting you are talking about skimboards.  Those are small and your resin will go a lot further with them.  Hopefully the foam you’re using is real heavy so you don’t have to put a lot of glass over it.  

 

Sidenote - I thought the reason you were trying the seal the blank was because you already had polyester resin on hand.  If that’s the case then you don’t need the VE resin anyway.    If you don’t have the PE resin on hand then I think you’re better off just sticking with a surfboard epoxy.  The difference in cost really is minimal unless you’re wasting a lot.    Using PE and - to a lesser extent - the VE resins involves using acetone for clean up and putting up with noxious fumes.   Besides, the epoxies are a better resin all the way around.  

I was talking about wax+styrene mixture, and it is necessary if you’re planning on sanding the VE resin.   I’m no expert but the way it was explained to me is that the wax rises to the surface of your sanding coats and smothers the resin, cutting off the oxygen.Then the resin can set dry.    I’ve tried the smothering thing using plastic film over the finish coat on a ding repair and that works too, but you can’t do that with an entire board.   

 

Maybe one of the pros will pop in and offer a better suggestion.  

 

Oh, and one more thing - the VE resin has an amber color.  It’s noticeable.  I almost always tint it when I use it.  It’s a little bit of a hassle but I like the resin’s strength and flexibility so much better than poly.    My glassing schedule when I started to use  VE (back when I was still doing polyurethane blanks) was to use VE for the lamination and Polyester resin for the fill coat and finish coat.  On a few of the boards I later noticed that the finish would develop some minor surface cracking that didn’t extend into the lamination.  Gary told me that was due to the VE was flexing more than the PE.  So I started using VE+ the sanding agent for my finishes.  That seemed to work better although I don’t think the VE resins would be very good for glossy finishes.    Your mileage may vary.