I would not use weld-on 16 for this. I'd use weld-on #40, which is a two part polimerizing cement. It's much stronger than #16. Who built your skimmer? If it's one of mine, I'll fix it for free, if it's someone else's I can probably do it for almost nothing (a frag or two would be fine) if you bring it over dry and clean. It depends on how bad the leak is.

But, there is another concern if it's on a seam and has started leaking, rather than a seam that leaked from the beginning. The concern is that it might be a sign that the seam is weakening, which could possibly lead to a very bad day, most likely ten minutes after you leave on a nice vacation.