Stopping an etch mid process.... how?

I began an etch on a large 12" diameter copper disk by wiping it on.
After 1 1/2 hours of little results, I taped the back and laid it
face down in shallow ferric chloride. The etchant was cold and no
movement except I would move the container around periodically.
Still almost nothing after 4 hours. I realized my etchant was too
old AFTER I got into the process. I thought, even old, given enough
time it would etch. I had had to iron on the toner resist 3 times to
get a good resist, so I didn’t want to lose the resist. I wiped it
off, pulled the tape off the back, patted it dry and will try
tonight with fresh etchant.

So, when you get into a predicament like this, how do you postpone
the process safely? Being my own fault about the used etchant not
withstanding, I still was up till 12:30 am to try and deal with
this. What can one do in this situation?

(And I learned that ferric really burns in a cut.)

thx brenda

Just stop it the same way you would after ending a successful etch -
whatever your neutralizing process is should still work, shouldn’t it?
As long as it doesn’t damage your resist. All you need is to
neutralize the acid on the piece so it quits etching (although it
sounds like it wasn’t etching anyway in this case. so perhaps just a
really good rinse would work in this case?).

Good luck!

Beth Wicker

So, when you get into a predicament like this, how do you postpone
the process safely? B 

just rinse it off till ready to proceed. If you want, rinse in a
solution of baking soda, though I’d think that’s not totally
required. If the copper, while waiting, starts to oxidize, no harm
done, that will come off when you resume etching.

Just submerge your item in water with baking soda to neutralize the
acid, then wash the item well to wash off the neutralizing solution
and let the item dry. You’ll be ready to go again when you get a more
active solution of ferric.

Sandra Graves
Isis Rising