# AP method



## bswartzwelder (Mar 30, 2012)

When using the AP method to strip fingers from printed circuit boards, is there some "rule of thumb" as to how much AP solution to use? Just enough to cover the fingers? Twice that amount? I hate to waste chemicals, but want enough to do the job without having to come back and add AP solution five or six times. Thank you.


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## publius (Mar 30, 2012)

As I understand the process, and wiser men will correct me if I am wrong, if you add air bubbles to your AP it will work indefinably with only an occasional addition of HCl.


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## maynman1751 (Mar 30, 2012)

publius said:


> As I understand the process, and wiser men will correct me if I am wrong, if you add air bubbles to your AP it will work indefinably with only an occasional addition of HCl.


Right Publius!
AP is reusable until it becomes too saturated with copper (very dark opague brown). A fish tank bubbler is cheap to run and works great! Just fuse the end of a piece of vinyl tubing and with a hot needle, poke some holes through the last inch or so to make a bubbler. The fish tank stones won't hold up to the acid.


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## Dravin (May 9, 2012)

sorry to sound stupid but what is ?


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## publius (May 9, 2012)

AP is an acceptable shorthand for acid (HCl)/peroxide. (H2O2).


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## butcher (May 9, 2012)

The true name is Copper II Chloride etching solution but has also been called (AP) (acid peroxide solution) or also called Hydrochloric acid and 3% hydrogen peroxide solution (HCl /3% H202), and other names, It is used to etch copper circuit board traces when making circuits circuit boards for use in electronics circuits, very similar and replacement for to ferric chloride etching solution.

http://www.google.com/#hl=en&gs_nf=1&cp=15&gs_id=1c&xhr=t&q=circuit+board+etching&pf=p&sclient=psy-ab&site=&source=hp&rlz=1R2RNQN_enUS457&oq=circuit+board+e&aq=0&aqi=g4&aql=&gs_l=&pbx=1&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=4cf4daa8884778de&biw=1024&bih=583


When using copper II chloride solution to etch copper the volume of the solution grows as you use it, so I would start with just enough to cover material, you will either add air bubbles or 3%peroxide solution and HCl as copper I chloride forms, as you etch copper the volume increases of the solution as you rejuvenate it for use to dissolve more copper into solution.

If you have not studied the document on this solution I suggest anyone using it should it can be found on Laser Steve's web site (look for one of his post's for the link, if you have not visited his web site your missing some good information on this and other processes, Laser Steve was instrumental in adapting the copper leach solution to what we do here, reading his early posts on this subject can also give you a better understanding of its use here.


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## lazersteve (May 10, 2012)

Check out the Acid Peroxide Q & A thread for complete details on the Acid Perxoide process.

Steve


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