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


Step 3: Add PCB and you're Etching.

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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akro1235 months ago

Thanks sooo much, this was my first time etching, and i didnt bring enough money to radioshack to buy the etch lol, this worked great!!

ew00549 months ago
It helps to have a pan of hot water underneath and partially-submerge your etching tank into the hot water to transfer the heat. Use two tupper containers of the same size so they nest easily, preventing spillover.
Hec0311 year ago
This stuff is wicked cool. I love this etchant. It's taking me about 20 minutes to get it to fully clear the copper from the board, but my features and traces only leave behind about 1% of the copper on the board, so given the large amount of copper that has to be dissolved it's moving very fast. Putting a board is the best way to prime the solution. Don't bother with any other method. It's a waste of time. Just get your board ready mix the Acid and Peroxide 1 to 1 and put the board in. The rest takes care of itself. I do agitate the solution periodically and will leave it out over night so it can oxygenate but other than that, this stuff is perfect for a DIY project.
Electricsrb3 years ago
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?

I have been playing around with this etchant as I have used ferric chloride in the past and it stains and is a pain to dispose of (properly). I mix up the Peroxide (3% Drug store version) and Muriatic acid (Dynamic Paint Products, no %info on bottle). The Muriatic acid definitely fumes when you open the bottle so it's strong.

I mix at 2:1 Peroxide to HCL and it etches the first boards just fine (just a couple minutes). The resulting solution is a light green and after a couple boards the colour doesn't change much and it pretty much seems to stop etching. I didn't see if it took 8 hours but after 30 min there was still copper.

I too am trying to figure out what may be going wrong. I tried adding more HCL to the bath and it didn't seem to do anything so I added some peroxide to match the HCL I added but no result (in the 30 min I had the board in). My etchant never gets that dark green/brown I see in your images. Any advice or tips?

The Real Elliot (author)  Electricsrb3 years ago
8 minutes is about right. 8 hours, not so much.

What is the concentration of your acid? Is the peroxide fresh?

At this point, there's only two ingredients, so that makes troubleshooting easy....
jaydenr3 years ago
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?
"Disolving the copper" is what it's supposed to do...that's what etching is: dissolving the unprotected copper from the board.
Luke Ferg4 years ago
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.
fenderfreek4 years ago
Couldn't you just place a piece of copper wire or something similar in the solution and use that to initially "spike" the mix?
Ziggy9314 years ago
Where can I get a PCB like that?
 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
shaunak6 years ago
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.
Stokes shaunak4 years ago
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.
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.
captsomer5 years ago
Will this work for etching Aluminum as well?
The Real Elliot (author)  captsomer5 years ago
Not sure, but my best guess is "not for very long." The whole point of etching using copper oxide is that you're pulling copper off the board and then re-oxidizing it for later re-use. If you just want to etch aluminum there must be etchants that are better-suited to the job.
chemical6 years ago
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