Found a leak under right rear of car where gas tank is.can i fix it myself?

So i could use this if i were to find a crack in the tank itself? great! thanks! ok so i just jacked up the right side to get a clear view of the underside. it seems the leak is localized to the right side just behind the right rear wheel. i wiped the side and underneath the tank to dry up the area. but i couldnt find any sign of damage. even when i turned the engine on while it was jacked and pushed a little on the gas pedal, there were no new wet spots or signs of leaking.....until i lowered it. as soon as i slowly released the two blocks and two jacks , it started dripping heavily. down the side that i had just wiped dry, and so much so, that a good four to eight drops spilled onto the floor. so ive narrowed it down to either the seal between the bottom and top halves of the tank(on the right side), or somewhere on the right side of the upper half of the tank. any thoughts?

Have to know exact location of leak. If it is the seal between halves, probably need a new tank. If it is a small hole or crack, then try the compound I showed you.

ok thanks so much!!! now i just need to find a diagram or instructions on how to drop the tank, or at least how to access the top half. thanks again!!