My 14' aluminum jon boat has the bottom liberally coated with asphalt
sealer, or "black mammy" as my dad calls it.

Mind you, this is not a boat I show off, or brag on. It's the one I use
for running a trotline, or poking around in backwaters. The
1950's-vintage Johnson 3hp is plenty to push it along with the kids and
me on board.

For a $150 jon boat, I wouldn't worry about having it riveted or welded.
A little tar should do the trick.

Chuck