Jim, that is a good tip.
Thanks
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On 3/5/2019 12:45 AM, Jim Higgins wrote:
Received from Harvey White at 3/5/2019 01:13 AM UTC:
When you do the etching, you'll want a bubbler of some sort.? The HCL/H2O2 etchant works very well until you run out of H2O2, perhaps 30 days.
Use the same bubbler you use to agitate the solution when etching to rejuvenate the solution when it gets to the point that it is no longer a nice emerald green. It will turn emerald green after a number of etchings due to dissolved copper. It's starting to become spent when it starts turning brownish. That's the time to bubble air thru it 24/7 until it's emerald green again. When you find you can't rejuvenate it by bubbling air thru it, add a bit of HCl. No need to add H2O2 if you rejuvenate by bubbling air thru it... which has the advantage of not diluting the solution since drugstore H2O2 is about 94 - 97% water. Rejuvenating by bubbling isn't a fast process, but you'll have to etch a heck of a lot of boards to fall behind.
Make note of the liquid level before an extended bubbling session and dilute it back up to replace evaporated water if you see that the level has dropped.
Jim H
