Stop using Ferric Chloride etchant! (A better etching solution.)

Step 3Add PCB and you're Etching.

Add PCB and you\
Toss the PCB into the solution and it'll take off.

If this is the first time you're using this batch of solution (and I presume it is), it'll etch super-fast. This small board took only 2 minutes. Yikes!

Since I use a deep container, I tend to swirl it around as it etches. This stuff is so active, though, that I'm not sure it's necessary.

Keep the window open for ventilation because the starter solution gives off a little chlorine gas. (The end-etchant gives off much, much less.)

Also, note how the etchant gets greener over time as it eats away the copper. This is good news.

What's happening is that you're dissolving the copper from the board and turning it into cupric chloride. In the long-run, the cupric chloride will be doing most of the etching (instead of requiring disposal). For now, just watch your solution turn light green. Next time you use it, the color will deepen.

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16 comments
Jan 11, 2011. 12:10 PMjaydenr says:
Help, my mix just dissolves the copper. My muriatic acid doesn't tell me what percentage the acid solution is, it just says "industrial strength". will this start etching when more copper is dissolved in to it? what can i do?
Jan 26, 2012. 11:37 AMcincodenada says:
"Disolving the copper" is what it's supposed to do...that's what etching is: dissolving the unprotected copper from the board.
Dec 5, 2007. 6:41 PMshaunak says:
Is it OK to drill the holes for the components before etching? I have four 16pin ICs on my board and drilling them later will be a real pain.
Dec 26, 2009. 8:44 PMDavad says:
Yes you can. Industry drills the hole first for making vias. The holes are drilled then the board and the via holes are electroplated before etching.
Dec 27, 2009. 8:26 PMshaunak says:
 Thanks for the insight.
Jan 15, 2010. 4:15 PMLIELOREN says:
 Better etching first, it makes the drilling part way easier.
Mar 3, 2011. 2:33 PMGTechno13 says:
Agreed, drilling can let the echant reach under your resist a bit. I find that the copper circle also helps center the bit.
Oct 5, 2009. 8:20 AMStokes says:
I've found drilling after the etching to be better. In the transfer, I make the holes just tiny dots so I know where to drill. This way, I am sure that the copper completely surrounds the hole -- no crescent moons of bare board on one side or the other.
Dec 8, 2008. 12:47 PMhaptotrope says:
I'm not certain about this specific etchant, but its speed may make it necessary to coat the inside edges of the holes with a resist to keep the acid from eating the board from the side of the hole -- and under the printed resist.
Feb 22, 2011. 8:25 AMElectricsrb says:
Mine board took 8h to etch. The solution is perfect I swirl the container around, but it's taken me a loooooong time to fully etch it. Am I doing something wrong?
Jul 6, 2010. 12:46 AMLuke Ferg says:
Is the etchant once mixed supposed to be clear? Mine went orange. I used 3% hydrogen Peroxide and 30% hydrochloric acid. It still etched the board but it took much longer than 2 minutes for my board which was a little larger than yours but I wouldn't have said significantly so. It probably took about 15 - 20 minutes for the first batch.
May 8, 2010. 5:12 AMfenderfreek says:
Couldn't you just place a piece of copper wire or something similar in the solution and use that to initially "spike" the mix?
Jan 23, 2010. 9:54 PMZiggy931 says:
Where can I get a PCB like that?
 
Feb 1, 2010. 12:51 PMMinifig666 says:
 In the US, your local (or on-line) Radio Shack should sell them. In the UK, Maplin stocks them. Elsewhere a Google for 'Copper Clad Board' should do the trick. Hope this helps
Sep 12, 2008. 12:17 PMcaptsomer says:
Will this work for etching Aluminum as well?
Oct 6, 2008. 2:15 AMWragie says:
Plain hydrochloric/muriatic acid will easily etch aluminium.
Jul 30, 2008. 1:39 AMchemical says:
While what you have described is a great etchant you are also asking to kill yourself. The chlorine gas that can be produced in sufficent quantity to be fatal,especially if you use peroxide stronger than 3%. Be very careful

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