fair enough, i described that badly.
you are right, the idea is to find a wax that will adhere to the ski, but not to the snow.
But that thin film of water you speak of is created by the friction of the wax on the snow - its a crucial part of it.
I guess my point should have been, if theres wax on your skis and wax on the rail, those two should not make sliding easier as it does on snow.
i dont know why some say it works - its totally fucked up any attempts in which ive used it.
as for the guy who dissed me using oil, try it. im not the best rail grinder in the world, but i sure as shit makes the pvc on my backyard setup slide well.