Homebrew PCBs

Before I posted, I did a search in the archives for "vinegar". Returned several hits. Here is a link to a web article where the etching process does indeed use household vinegar (with drugstore-strength hydrogen peroxide and table salt.)

http://quinndunki.com/blondihacks/?p=351

On 8/19/2011 11:16 AM, kx4om wrote:
>
> Before I posted, I did a search in the archives for "vinegar". 
> Returned several hits. Here is a link to a web article where the 
> etching process does indeed use household vinegar (with 
> drugstore-strength hydrogen peroxide and table salt.)
>
> http://quinndunki.com/blondihacks/?p=351
>
> _
Not 100% sure about the chemistry - it's been 60+ years since chem 
classes, but as I recall, vinegar (5% acetic acid, HAc) + Salt (sodium 
chloride, NaCl) => HCl (hydrochloric acid) + NaAc (sodium acetate?).  It 
would be a very weak HCl, and when combined with the drugstore H2O2  
yields a very weak version of the same etchant as  the CuCl version 
(just add copper).  I have no idea what the NaAc might contribute to the 
etching process. The very weak acid/oxidizer solution  tends to agree 
with quindunki's report of very slow etching time__ 
<http://quinndunki.com/blondihacks/?p=351> (1 hour +).   It obviously 
works for him, and possibly the very weak etchant contributes to his 
success with fine traces.  To me, the commercial HCl is easier and 
faster than messing with kitchen condiments.

Just my opinion - - - YMMV.

Norm
W6NIM


[Non-text portions of this message have been removed]

>Here is a link to a web article where the etching process does indeed use 
>household vinegar (with drugstore-strength hydrogen peroxide and table salt.)

     I've used this to remove nickel plating from a brass substrate. The 
brass was very shiny underneath and I wondered if it was being removed as 
well, but I never cared enough to test it on the copper on a pcb. 

     For anyone who cares, this is what I did:

     Start with about two ounces of white vinegar
     Dissolve about two tablespoons of non-iodized table salt in the 
vinegar
     Add about two ounces of plain drugstore peroxide

     Stir with part to be etched until the desired material has been 
removed.

     In reality, it was: slop vinegar into a paper cup to about 1/3 full, 
pour two piles of salt in hand and dump in, stir, slop in peroxide to 
about 2/3 full, stir with plated part. It went faster than I anticipated.

     It might be slow for a pcb, but it has advantages for those who 
don't want HCl around the house - the kids can only get into so much 
trouble with a bottle of vinegar.

     -Gary