HCI h2o2 issue

Posted by ninemag on Sep 13, 2020; 6:33am
URL: http://guitar-fx-layouts.238.s1.nabble.com/HCI-h2o2-issue-tp49160.html

I’ve been etching recently using a 2:1 h2o2/HCI etchant with great success. Tonight, while attempting to etch a small board, I was unable to remove all the copper from the board. I prepared a fresh batch and tried again. Some came off, but not all.any ideas, or obvious issues I’m not seeing?
Thanks for the advice and help