Perhaps you should try buying peroxide at a real store. A pharmacy will have fresher peroxide; a beauty supply store will carry stronger concentrations.
Fresh peroxide and muriatic acid works extremely well. There is no need to start adding more chemicals to the mix. That will cost you time and money that could be better spent on good peroxide and laying out circuit boards.
Donald.
----- Original Message -----
> From: "Kevin Byrne kbyrne10@... [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com>
> To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
> Sent: Thursday, November 24, 2016 3:46:30 AM
> Subject: [Homebrew_PCBs] Re: Copper Clad Board
>
> I am right back to square on not being able to afford proxion and am looking
> at carbide drill and press seen at jameco.com but with no spec sheet.
> Jameco.com seems to be a good site, company ect. My peroxide bought at
> dollar store is the cause of long etch times. Has any one tried the
> edinbourgh etch method? Will food grade citric acid like ones sold on
> amazon.com work ok?