a large, strong one that holds the whole are that you need to epoxy... if you cant do that use a piece of wood on either side of the ski, clamp that so it holds the whole area.
you can just go to Walmart or something and get some stuff called Two Ton Epoxy. It comes in two syrnges and you mix it together. Its waterproof, and works good. and its only like 2 dollars for a shit ton of it.