Don't freeze it or use air pressure to remove the dent. You may end up bending the tank in ways you can't imagine, or splitting a seam. Check into a paintless dent removal guy, they have the tools to work through the filler hole and can work magic.
I may have to do that. Thanks for your input. Is that a fairly cheap job? I’m trying to save as much money as I can throughout this build
You can do it yourself if you have a decent bench vise.
Grab some 3/8” steel rod, about 30” of it. About 4” from the end, bend a 45* in it using some heat to do so. Grind the tip into a blunt taper. Heat the middle of the length that is straight and put a slight curve into it. Bend the final 6” at 90* to make a handle. Wrap that with some duct tape.
Slide the bar into the tank with the tank securely fastened to the bike for leverage. Remove the paint and point a light flat along the side so you can use the shadows to identify the position of the dent and your tip. Using the tunnel as leverage, gently push the edges of the dent first. Working yuor way inward. You should get it very close.
Follow up with a brass blunt punch to tap down a pry marks and high spots. Lastly, a fine file to flatten them if needed. If you need more curvature for the tip to reach the side, pull the bar out, heat it, bend it, let it cool.
I’ve done dozens of these tanks with this method (store bought tools). I gave them to a pal a couple of years ago who was starting in the business and needed a bumpstart. But I’ve made plenty of them following this method. The metal will move easier if warm, and don’t get in a rush, push, move, push a little, move, and so on. Don’t try to get it all out first push. Patience or you’ll make a worse mess..
