Replying to Refinishing Afterbang topsheets

i just picked up a set of very gently used 2011 afterbangs set up with some markers for dirt cheap and was curious if i could sand and stain/seal the top sheet since they're all wood like a skateboard. i have experience with refinishing all sorts of surfaces and wood things haha. i searched the web for hours and found nothing on refinishing top sheets on any sorts of wooden skis so decided to come to the ns community for advice once again. the sanding off of the current graphic would be easy and staining, im just baffled on what to seal them with; it would have to be something resistant to water and extreme cold and durable against collisions because i ride a lot of park. any advice is welcome.