
with David, a Linear Plating Bubble under the copper plating. Something was on the blank when it was plated prior to upsetting (making the raised edge and preparation of the Planchet). It could have been a hair, fiber, or liquid that got on the zinc core, this then started the zinc corrosion effect and gasses to form under the copper.
Edited by Crazyb0
03/24/2018 01:00 am