HCI h2o2 issue

[ninemag]

I’ve been etching recently using a 2:1 h2o2/HCI etchant with great success. Tonight, while attempting to etch a small board, I was unable to remove all the copper from the board. I prepared a fresh batch and tried again. Some came off, but not all.any ideas, or obvious issues I’m not seeing?
Thanks for the advice and help

[Silver Blues]

The etchant that you say failed to remove all the copper from the board, what did it look like? Was there a bunch of brownish solid floating around in it?

Your new batch, did it turn green when you performed the etch?

[ninemag]

No discoloration at all, no residue. Solution turned light blue/green. After the first attempt there were small amounts between some of the traces, and a larger area just off the board, on the excess margin (I file it down  to make it pretty after etching lol). After second attempt, the copper inside the traces was gone, but the larger area seemed unaffected. 

On Sun, Sep 13, 2020 at 1:17 PM Silver Blues [via Guitar FX Layouts] <[hidden email]> wrote:

The etchant that you say failed to remove all the copper from the board, what did it look like? Was there a bunch of brownish solid floating around in it?



Your new batch, did it turn green when you performed the etch?

I stand watching the steam-liners roll by...

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NAML

[ninemag]

Typically yes, the solution turns green within a minute or so

On Sun, Sep 13, 2020 at 1:22 PM Jeff Steele <[hidden email]> wrote:

No discoloration at all, no residue. Solution turned light blue/green. After the first attempt there were small amounts between some of the traces, and a larger area just off the board, on the excess margin (I file it down  to make it pretty after etching lol). After second attempt, the copper inside the traces was gone, but the larger area seemed unaffected. 

On Sun, Sep 13, 2020 at 1:17 PM Silver Blues [via Guitar FX Layouts] <[hidden email]> wrote:

The etchant that you say failed to remove all the copper from the board, what did it look like? Was there a bunch of brownish solid floating around in it?



Your new batch, did it turn green when you performed the etch?

I stand watching the steam-liners roll by...

---

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http://guitar-fx-layouts.42897.x6.nabble.com/HCI-h2o2-issue-tp49160p49161.html

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NAML

[Silver Blues]

Right okay, yes the green colouration is normal and in fact beneficial to the etch - the acid alone cannot etch copper (which is why you add the peroxide in the first place). You can "strengthen" the etchant by just dissolving a bit of copper wire in the fresh solution.

Household peroxide is only ~3% hydrogen peroxide, which is not very much. It's stored in dark bottles because it is light sensitive, and regardless isn't extremely stable so will decompose over time. If the peroxide you used was old, it might explain inefficient etches as well.

[ninemag]

The h2o2 stability clears it up- was an old bottle... same one I e been using, but old.

Cracked open a fresh bottle and had no issues.

I’ll grab some cooper wire though, good to know 

Thank you!!!

On Sun, Sep 13, 2020 at 3:20 PM Silver Blues [via Guitar FX Layouts] <[hidden email]> wrote:

Right okay, yes the green colouration is normal and in fact beneficial to the etch - the acid alone cannot etch copper (which is why you add the peroxide in the first place). You can "strengthen" the etchant by just dissolving a bit of copper wire in the fresh solution.



Household peroxide is only ~3% hydrogen peroxide, which is not very much. It's stored in dark bottles because it is light sensitive, and regardless isn't extremely stable so will decompose over time. If the peroxide you used was old, it might explain inefficient etches as well.

I stand watching the steam-liners roll by...

---

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NAML

[Silver Blues]

No problem! Glad you got the issue sorted

(Be careful to only add a bit of wire if you're going to go that route - just enough to make it transparent green. If you add too much, you'll be having the opposite effect on the solution. Typically the first board you etch will achieve the same thing.)

[ninemag]

Thanks for the tip!

On Sun, Sep 13, 2020 at 3:57 PM Silver Blues [via Guitar FX Layouts] <[hidden email]> wrote:

No problem! Glad you got the issue sorted

(Be careful to only add a bit of wire if you're going to go that route - just enough to make it transparent green. If you add too much, you'll be having the opposite effect on the solution. Typically the first board you etch will achieve the same thing.)

I stand watching the steam-liners roll by...

---

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NAML