i'm almost embarrassed to show people my tank building "method."
i start out all professional with posterboard to mock up a full size tank, but then...
i just trace out the pieces, cut them out with regular cheap tinsnips, clean up the edges, and then do this bizarre, "house of cards" balancing act, holding pieces down with bricks, tapping them together with a hammer, prying them in different directions with a butter knife...
i just solder a few inches at a time, then re-adjust for the next few inches, until somehow, magically, it resembles a gas tank when i'm done.
i was thinking of making a video, just to show how simple it is, and that it can be done with no professional tools of any kind (everything but the copper sheet is available at ace hardware,) but i don't want to give away all my secrets, and i don't want 20 people telling me "you're doing it wrong..."