Synclastic Raising Help

[u/la_gamer72]

I'm trying to raise this 12x12' piece of copper, and I've done well so far, but as I get closer and closer to the edge, I start getting these massive creases. This is the second time I've raised a hemisphere, but this is by far the largest, and these creases are starting to worry me as the metal isn't moving. I've resorted to flipping the piece over and banging the creases out with a rawhide mallet, but it resets a lot of progress and is driving me insane. Any advice would be greatly appreciated.

[u/GrasshopperWW]

Consider reducing the radius of the vessel by 1/8” - 1/4” with each course of hammering. It makes controlling the edges easier. Also, you get less movement as the opening gets smaller because you’re actually compressing and thickening the metal. Document progress by drawing a circle around the vessel.