Either ammonium persulfate or sodium persulfate is used by commercial pcb
manufacturers. They do not use ferric chloride, not for decades. Only
hobbyists use the stuff. I'm using a peroxide-muriatic acid-sodium chloride
etchant. It's very cheap, and the chemicals are available either in a drug
store or at places such as Home Depot (for the acid). I use it "one-shot."
I use just enough to do the board I'm etching and then toss it away. It's
that cheap. This way, It works the same way--etch times, etc.--every time I
use it.
73,
Todd
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K7TFC / Medford, Oregon, USA / CN82ni / UTC-8
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QRP (CW & SSB) / EmComm / SOTA / Homebrew / Design
On Tue, Feb 19, 2013 at 9:12 PM, tda7000 <Tda7000@...> wrote:
> ∗∗
>
>
>
>
> I have used the toner transfer method with the laminator described here:
> http://ultrakeet.com.au/write-ups/superfuser
>
> I have not used Press-n-peel blue, just magazine paper. However I have not
> had undercutting (that I ever noticed!). I used old Ferric Chloride and
> later on the Hydrochloric acid and Hydrogen Peroxide mixture. Both worked
> great.
>
> http://ultrakeet.com.au/write-ups/etchantComparison he describes Ammonium
> Persulphate as being much worse than Ferric Chloride. I have never used
> Ammonium Persulphate.
>
> I don't know if it's any different to Sodium Persulphate in terms of
> undercutting, but if his article has any truth behind it I would probably
> try something else.
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "phil.quinton@..." wrote:
> >
> > Hi,
>
> First post, hopefully one of many..
>
> To cut a long
> > story short, I'm having problems ∗after∗ etching with Sodium
> > Persulphate
>
>
>
> In short, it appears to be etching ∗under∗ the
> > toner somehow.
>
> My guess is that the etch tank is no
> > longer getting to the right temperature ( ~ 45 degrees ) and I'm etching
> > too long with the agitator on. I'm going to get myself a temperature
> > probe to confirm.
>
> Has anyone had a similar experience ( Etch
> > looking fine until the toner is removed )?
>
> Thanks in
> > advance,
> Phil.
>
> >
>
>
>
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