I'm new to this whole forum thing. I'm Doug from Sydney, Australia and I'm a build anything nut. I own a Moto Guzzi 850 Le manns MkII. Its now a completely differant machine. If I don't like it, it gets replaced with something I do like & for the most part I'll make the it myself. Now, I'm making an aluminium tank for it. How often do you anneal a 2mm sheet. It will be a two part design, the upper section carrying the whole shape, so its got a lot of crown in it, as you can imagine. Probably taken on more than I can chew, but you never know till you have fun trying. You guys seem to be of the same sort of thinking. Hope you can help.