Etching Holes ...

[Kevin Lightner]

I question whether the acid would eat straight down and not sideways.
Acids like edges. (You can even sharpen files with Nitric acid.)

When glass etchers use Hydroflouric acid to etch glass, they say there is a
limit to the depth of the
cut, since the acid wants to eat sideways too.

Maybe this is why we don't see too many acid based metal shops. :)

I also question what substance the resist mask would be made of to resist a
strong acid.

My dissolving two cents worth.

K