Electronics > Beginners
Laminator recommendation needed for PCB transfer method.
Fred27:
--- Quote from: LateLesley on March 22, 2019, 10:13:08 pm ---The trick is not to use ferric chloride. A friend put me on to an idea of reuseable etching solution. I just googled an article for you, but you may find some more if you look. :)
https://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/
--- End quote ---
This gets brought up again and again. I've no idea why though. If you look a little closer you'll find that this "better etchant" is far nastier then Ferric Chloride.
KL27x:
--- Quote ---This gets brought up again and again. I've no idea why though. If you look a little closer you'll find that this "better etchant" is far nastier then Ferric Chloride.
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If you are truly using cupric chloride, it is no nastier than ferric chloride. No more acidic, no more corrosive, no more environmentally bad, and the stains are far less to deal with. In a permanent setup, is convenient because you never have to change out the etchant when it gets old/spent. You just remove a tiny bit of it and add a bit of acid every now and again.
The problem with this page is the way he presents it leads a lot of people to assume HCl and peroxide IS the same things as cupric chloride, and you just reuse it over and over even though it gets slower, just to be environmentally friendly. He doesn't state this, exactly. But they way he presents it, some people get this impression. To the tune that someone mixed up several gallons of 3 percent peroxide and muriatic, just for making one board, and thinking it is a good etchant to begin with, and assuming it will inevitably work forever and slowly turn into cupric.
And you can't get the best etching results using it the way he does, period.
He does state that cupric is more environmentally friendly compared to ferric, because you don't have to throw it away. And that's really not true. You can collect your excess spent ferric and put it in a fancy bottle, if you want, just the same as what to do with your excess cupric. Or in fact, you can continue to use your spent ferric in the same way as you would use cupric. So the title of "Stop using Ferric Chloride!" for environmental reasons is ironic, because you can continue using it, indefinitely, in order to "save the planet." The copper salts/ions are the environmental problem; the iron portion of the spent ferric is not an issue for the environment, nor for any septic/sewage treatment system. It's the copper, same as you get with cupric.
The way I understand it, the number one use of ferric chloride, tons per year, is to treat sewage water.
Wimberleytech:
--- Quote --- You can collect your excess spent ferric and put it in a fancy bottle, if you want, just the same as what to do with your excess cupric.
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I polished off a fancy bottle of tequila the other day and I decided...after reviewing this thread...to use it for my spent ferric chloride.
"push the bottle down the road" so to speak
castingflame:
I have been using sodium persulfate. What is the score with this.
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tautech:
--- Quote from: castingflame on March 28, 2019, 07:04:57 am ---I have been using sodium persulfate. What is the score with this.
--- End quote ---
So was I.
Has to be heated to be effective and it's a 'one etch' solution whereas either Ferric Chloride or Cupric Chloride give multiple etches and can be rejuvenated.
Being a 'one etch' solution it's more wasteful IMO and the reason why I changed to an HCl based solution that slowly can be converted to a Cupric Chloride brew.
There's some initial outlay with HCL and Peroxide but it's a single one time cost that for me was no more than a couple of purchases of Persulfate.
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