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Step 3Add 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.
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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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?
Thanks!
1. i polish it witch some polishing paste, dont forget edges
2. clean the result with some alcohol or similiar to remove the paste and any smear (fingerprints), this can protect copper from etching away too, best thing is to use gloves from this point. dont touch the copper board with your hands
if it's polished and clean, its ready to be sprayed with photoresist or for hand drawing ...
i do all of this and i dont have problems, i use FeCl3
To me the plain HCL and peroxide solution seems useless unless you're just going to use it for one day. It won't last any time at all in this form. You can't store it in an airtight container because it will explode due to pressure building (a caution many people seem to forget on pages like this). You can't add more peroxide (or acid) to rejuvenate the solution because you're adding mostly water when you do this so it just makes things worse each time you do it. I can't figure out why people think it's so great. Maybe they're just using it once or I'm doing something horribly wrong.
I think the "end" solution of cupric chloride is the only proper thing that will last. I'm in the process of trying to make this but it's slow going and difficult to manage. What I did was use the same 1 part acid to 2 parts peroxide and then immediately start dissolving a specific amount of copper based loosely on the formulas on that other page (Adam's stuff; he doesn't say how to do it with peroxide) with a bubbler in the tank. After a couple of days I still have a little copper left and my solution is turning brown. My specific gravity is somewhat low so I'm hoping evaporation will improve that. Not sure where to go from here. I don't know what my acid level is so I don't know if I should wait a while longer and hope it greens up with the bubbler or if I should add more acid (that will reduce my specific gravity even more, not desirable). The hardest part of this seems to be figuring out if you need more oxygen or if the solution is out of acid because you can't tell from the color of the solution alone. I wish a simple pH test would work for the acid test, the titration procedure seems like a lot of hassle if you don't have lab equipment.
Just an update on my original solution. Once all the solid copper was gone it almost immediately turned green. I added more acid and did the titration test. I'm currently at 3 M acid (perfect) and specific gravity of 1.2 (too much water from my initial peroxide, for sure).
What is the concentration of your acid? Is the peroxide fresh?
At this point, there's only two ingredients, so that makes troubleshooting easy....