Hey, need your advice. I am new to carbon skinning, and this is my first piece Im trying. So I took a PC+ABC piece, it had some kind of rubber like coating. I removed the coating fully, but each time I tried to coat it with epoxy resin basecoat it seems to go watery like structure and does not go into sticky state after 3 hours. I tried searching the web, but no look. Anybody came across such issue? Why might this happen? The mixture is spot on, I tried both with cleaning the surface with acetone and just a cloth, incase it was the acetone causing the problem. 

Resin beading up like that is a sign of very little surface tension, which means no adhesion. Polycarbonate and ABS with some sort of rubber coating? You're never ever going to bond to that. Even without the rubber coating. ABS and Polycarbonate are low energy plastics and regular epoxies will bond poorly to them. 

You can't skin this in the regular fashion. You may be able to do it as an offset cover instead and bond it in place with a highly flexible polyurethane like Sikaflex. But those adhesive are so thick it may not look very nice.

Even tho Hanaldo is certainly right with the PC and ABS being hard to bond to, there is a fairly easy solution to this that works at least on ABS. Ski sidewalls are made from ABS more often than not and are usually flame treated to improve bonding.

First clean the surface with IPA. then with fresh 60 grit sandpaper key the surface. use a Bunsen burner and "paint" over the whole area. you can check if the surface tension changed by applying a drop of water which should not bead up but wet a big area.

Hope this helps!