whit3rd fired this volley in news:cc7dd172-8168-44f4-
:

ferrous chloride

Ferrous chloride doesn't rapidly enter into a double-displacement
reaction with copper. It's corrosive to most metals, but not like Ferric
chloride.

Ferric chloride works to etch copper alloys, aluminum, some stainless,
zinc...just about any alloy with metals more active than iron, but it
undercuts...

Why would you do a photo-resist for something like that?

If I were inclined to try to etch an 80" long piece, it would be with a
PSA resist film. (not ordinary 'tape', but a plastic resist with a
special adhesive that doesn't bleed underneath like regular tapes do.)

Lloyd