Brightscales
Harmless
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Registered: 1-10-2012
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Etching a PCB using H2O2 and HCl - a few questions
Hi,
I've been told a good etchant for PCBs (copper, essentially) would be a solution of distilled water, 10% HCl and 2% H2O2. I wonder about the safety of
handling this solution, as I've heard it may produce Chlorine gas. Either way, I will be conducting this experiment outside with proper eye
protection, and some thick latex gloves. Also, my container is made out of plastic.
Moving on. I have a solution of 10% HCl prepared and also a solution of 3% H2O2 (very little of it, however) so I was also wondering about the ratios
and how much of each should I use to create this solution (oh and, do I even need the water, or is it fine by itself since the HCl is already at 10%?)
Sorry about the "Chinese Wall of Text" there, but I'm slightly worried and would like to conduct this experiment ASAP.
Thanks.
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AJKOER
Radically Dubious
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There has been some discussion on this forum as to what exactly HCl/H2O2 is. The view is a cycling reaction acting as Chlorine water. I find per the
reaction:
HCl + H2O2 --> HOCl + H2O
the the mixture acts like Hypochlorous acid, which is capable of dissolving Gold, and in even dilute solutions attacks Iron.
Avoid fumes (Cl2 and/or Cl2O), but all in all, not as dangerous, in my opinion, as strong H2SO4 or HF or HBr or H3PO4, and as it is effective in
dilute solutions, much safer to work with.
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zed
International Hazard
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Seems to me that we used to do our board etching with a solution of Ferric Chloride.
Pretty easy to handle, very effective.
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CHRIS25
National Hazard
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Quote: Originally posted by zed  | Seems to me that we used to do our board etching with a solution of Ferric Chloride.
Pretty easy to handle, very effective. |
ferric chloride has its problems, I would use copper chloride, just as good and a lot more efficient. I haver been doing a lot of etching in copper
and use copper chloride, self-regenerating using an air pump so no need for expensive H2O2. Mixing HCL and copper is not dangerous at reasonably
small quantities (under a couple of litres). Fumes are not an issue if etching is done in a ventilated area.
The H2O2 will become exhausted quite quickly, it depends upon how much copper you are putting into the solution.
If you need any specific help I can offer you a ton of information, I collected charts and information from discussions on this forum, they are all in
PDF formats. If you have issues then I would be happy to send you the relevant PDF's.
[Edited on 3-10-2012 by CHRIS25]
[Edited on 3-10-2012 by CHRIS25]
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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