Start in the very middle if possible and work your way out in a circular pattern. Dont put transfer tape on it, take off as much of the backing as you can, go slow, and use a felt covered squeegee. A second set of hands to hold the opposite side your working on helps too. You'll need a heatgun or propane torch (hopefully no leaks on the truck so you don't go boom). You can also use some 3M Primer 94 on where the edges will be (just mark where it will be with a grease pencil. Apply 2-3" wide strip overlaping around perimeter and let sit 15min before putting on decal. Wipe off excess afterwards with Isopropyl alcohol), to keep from lifting. You will undoubtedly have some stretching towards the corners, so having no outline/border helps too since you can then trim it straight afterwards. You'll also need to post heat the vinyl so that it learns the shape of the tank.
Couple things ive done in the past is make my print 1in bigger and then trim it off square after putting it on (this takes some of the tension off the edge so it doesn't curl) and the other is try doing it with a scrap piece first (just don't push hard and no primer 94) to get a feel of how the vinyl will conform.
- use Grafityp ae38c or Arlon slx for this, that last one even shrinks nicely when you heat it, is nice stiff. I tried such round things with standard calendred polymer and didn't have success (had exactly the same thing going on), but that might be due to my newbie-status and limited experience with calendred for such things thanks to all courses being most cast-only-substrate-coursed (upsell anyone?)
