do a search and review the material, If you had 30% HCL, you needed to add
twice that volume of water, to get a 15% mix, then a teaspoon or so h2o2 --
Only to get it started, once you get some copper in there it becomes cupric
chloride, and will etch on it's own. Bright green is the color of good, dark
brownish green, add another teaspoon of H202,
Putting in as much h2o2 as you did probably burnt out the mixture or
exhausted it. I'd start fresh over
JT
----- Original Message -----
From: <Linux_Rules@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, January 18, 2004 9:47 AM
Subject: [Homebrew_PCBs] Problems with HCL/H2O2 etchant.
>
>
> Several weeks ago there was a thread about using HCL
> & H2O2 as an etchant. That was a god-send for
> this newbie/lurker. I have used A.P. mostly but am
> unhappy with the cost. F.C. is so nasty that I avoid it
> if possible. The HCL/H2O2 looked perfect.
>
> Last week, I finished my bubble tank (1 gal capacity) so
> I diluted the 30% HCL with an equal amount of D.I.
> water. Due to a brain fart, I don't remember how much
> H2O2 that I added - about 1-2oz, I think..? (Too much?)
>
> The solution was clear so I put in my first board and the
> etch was perfect after about 15 minutes (room temp). The
> etchant turned bright, clear green by the end of the etch.
> I left the bubbler on for about 1/2 hour after the etch. No
> visible color change after the etch.
>
> Since it worked so well for the first board, I assumed that
> I had it "made". Two days ago, I put in my second board
> (4"x6"). After 30 minutes, there was no visible removal of
> the copper, however the toner was sluffing off in the areas
> of large toner (copper flow areas). I pulled the board and
> dunked in a junk board. After 45 minutes, no etch.
>
> Hmmmm.......
>
> I haven't a hint of a suspicion of a clue as to what happened!
> It worked so well for one board, then failed miserably
> Does anyone on the list have any idea why this would fail?
> Unhappily, being a beginner with this, I have no equipment
> to chemically analyze the etchant.
>
> cheers,
> johnd
>
>
> "Life isn't like a box of chocolates ... it's more like a jar of
> jalapenos. What you do today might burn your butt tomorrow. "
>
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