I think many concentrations and mixtures will work. I've used 2 parts 3% H2O2 to 1 part HCl (30%) and it works fine, but it often takes 20-40 minutes to etch. I usually do my etching outside in between doing other things, so I like it done fast. The 1:1 of 12% H2O2 to 31% (approx) HCl is very fast, and suits my personality <smile>. I would suggest you experiment and see what works best for you.
Mark
-----Original Message-----
>From: Jim Tonne <tonne@...>
>Sent: Jun 13, 2010 4:48 PM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: Re: [Homebrew_PCBs] Re: Etching note
>
>
>About the use of muriatic acid and H2O2:
>
>It looks like most of you use 30% muriatic acid
>added to 12% H2O2.
>
>Do you then use that mixture as-is, or dilute that
>mixture down with water? If so, how much?
>
>- Jim W4ENE
>
>
>
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