hmmm... can't really go by volume of FeCl3 (Ferric chloride) and volume of copper. Wht you need to know is how many moles of each (chemists way of counting number of atoms or molecules) will react together. read about atomic weight, Copper weighs 29gram/mole whereas FeCl3 weighs 77g/mole.
And now you want to know how much ferric chloride can "eat" copper.
It takes two molecules of ferric chloride to "eat" one atom of copper and turn it into one molecule of Copper chloride (CuCl2). I think it was...
So you need 154g of ferric chloride to etch 29g of copper.
You have to know the concentration of your ferric chloride solution.
BTW, ferric chloride isn't an acid, its a salt like sodium chloride (table salt).
hope this answers your question.
--- In Homebrew_PCBs@yahoogroups.com, "RickS" <rgsparber@...> wrote:
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> Does anyone know the ratio of needed Ferric Chloride by volume to the volume of copper being removed? I am assuming 110F for the acid and constant agitation.
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> Thanks in advance,
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> Rick Sparber
>