Re: 18' pontoon dent removal?
The rivet gun may work but heat warps aluminum so you will at best end up with smaller wavy dents and a big shiny spot on the tube where you sanded it.
Suction cups may work on car fenders but won't on a tube, the metal is alot thicker, you can dent a car fender with your thumb, try that on .080 or .090 aluminum, not gonna happen.
I have tried bridge pullers and they just don't have the grip to do anything because the metal is too thick.
Paintless repair works because the guy gets in behind the metal and works it out with special tools, again, no way to get inside the dent.
I have repaired hundreds of tubes in my 21 years, it is very difficult to do it and have it look good, there is no bondo or paint to cover anything, as I said, it is only a small dent, I would leave it alone.