all thumbs wrote:
I use Sis404, 5200, sikaflex 61a etc and blue tape off the hardware or
window surrounds and so on applying a moderate layer of ikumpucky with
maybe a 1/8 inch border and wiping off the excess. When I peel the
tape there is never a good line like with paint, it's always ragged or
smeared. I've tried different wait times but it's never much
different. Is there a technique you salty professionals use? Thank
you.

Put down 3 layers of tape. Apply goop. Clean up. Remove top layer of
tape. Repeat twice.
If you find this still produces icky-looking edges, then refine your
technique