Leaking gas from gas tank

[gnarlycharlie]

So I've had a gas leak for quite some time now. It's annoying because it's deteriorating the plastic panel under my seat and staining my frame. I originally thought it was leaking from my sending unit, but I replaced that seal and nothing changed. I think I finally pin pointed it to the welded seams where the hinge is connected to the tank. Is this a common problem? And what's the best way to go about fixing it? I've had people tell me I can do a coating inside the tank to seal it up, and I've had other people tell me it should be rewelded.

Any suggestions?

edit: It's an '02 Monster 750 sie, forgot to mention that 

[ducpainter]

A search will yield hundreds of threads.

Long story short...

Braze the hinge plate to the floor of the tank and coat it.

I like POR-15 for steel tanks.