Learned new trick with vinegar - peracetic acid

Everyone (:-)) knows the vinegar/table salt trick to make dilute buffered HCl for derusting, but I read about a new recipe - two parts 5%
vinegar and 1 part 3% hydrogen peroxide. This will make a very dilute (about 1%) solution of peracetic acid, which will have a sharp odor so don't stick your nose in it! Besides being used to kill algae in ponds (diluted to about 10-50 ppm in the pond) it turns out it does a great job of making brass look new again after machining or heating. Make enough mix to submerge the brass, and wait overnight - voila! Also strips copper sheet clean after I blackened it with a torch, but didn't do a thing for oxidized 304SS. Don't know about rust on iron but I bet the salt would be better for that since the peracetic acid will be consumed pretty fast. It is a little slow since it is so dilute, but works great. I'm not really sure if the slow step is the formation of the peracetic acid or the cleaning of the metal. Maybe one day I'll do some experiments where I mix one batch and let it sit for an hour before adding metal while in a duplicate batch I dump everything together at the start, and even try adding some salt, or maybe not :-). Can't remember where on the Internet I saw this, so can't give the proper attribution, sorry.
Don't drink it, or soak your hands in it, and especially DO NOT get it in your eyes. It wants to glue your eyelids to the eyeballs and no one wants that. That's the high points off an MSDS for some 15-20% stuff. I really don't know how nasty this dilute stuff is so be adult about it.
-- Regards, Carl Ijames carl dott ijames aat verizon dott net (remove nospm or make the obvious changes before replying)
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On Wed, 01 Aug 2007 04:08:12 GMT, "Carl Ijames"

Interesting, duly noted, worth a try. I don't know jack squat about chemistry, but I've found that Wal-Mart peroxide mixed with lumberyard muriatic acid makes a very effective and fast etchant for copper-clad ciruitboards at way far lower cost than ferric chloride from Radio Shack. Warm FeCl works better for fine work as in traces under .010", but the cheap mix works nicely for less fussy projects.
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    --Got some weights/volumes to add to this hack?
--
"Steamboat Ed" Haas : A steaming pile of
Hacking the Trailing Edge! : obscure information...
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steamer wrote:

It's very easy to make ferric chloride - simply take hydrochloric acid and keep feeding it steel until it won't dissolve any more iron. At this point it's been "killed" and it will be nearly all ferric chloride.
Grant
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Two parts peroxide to one part muriatic by volume. It's not fussy.
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    [ ... ]

    *Which* peroxide? Hydrogen peroxide? That's the most common one, but it could be some other.
    Enjoy,         DoN.
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Yes, hydrogen peroxide. Here is a link to a great site on how to make pc boards by toner transfer, and he recommends the hcl peroxide etch: http://www.fullnet.com/~tomg/gooteepc.htm
Another etchant is copper (II) chloride. It's biggest advantage is you never have to throw it away. You can regenerate it by bubbling oxygen or air through it, or if you are in a hurry you can add hydrogen peroxide. Here is an excerpt from http://members.optusnet.com.au/~eseychell/PCB/etching_CuCl/index.html which is a very detailed website all about this method:
[quote] Of the several types of etchant chemistries the hobbyist can choose, acid cupric chloride (also called acid copper(II) chloride or just cupric chloride) is one of the more interesting types, since it has the ability to be regenerated, or replenished, without having to throw away the solution. This is the reason why cupric chloride is one of two main etchants widely used by PCB fabricators. The primary advantages of cupric chloride in a hobbyist prospective is that a maintained solution never becomes exhausted. The disadvantage is the extra work is required for occasional bath maintenance. People who sparingly etch circuit boards, will only want a temporary and low complexity etch method. For simplicity, you cannot get any easier than pouring some ferric chloride or ammonium persulfate in a plastic container, heat it a little in the microwave oven, and immerse the PCB. More serious people may go to the effort of setting up a vertical bubble etching tank. It is these people who may find it beneficial to own an etch tank that does not deplete or decline in etching speed. [/quote]
-- Regards, Carl Ijames carl dott ijames aat verizon dott net (remove nospm or make the obvious changes before replying)
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    Thanks for this -- and all that I snipped below.
    Enjoy,         DoN.
--
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On Thu, 02 Aug 2007 04:19:39 GMT, "Carl Ijames"

Interesting. I didn't know there was another web page about this. Here is mine for comparison: http://www.xertech.net/Tech/CuCl_ech.html
Not based on my own work, but from a book long out of print.
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On 2 Aug 2007 03:53:44 GMT, snipped-for-privacy@d-and-d.com (DoN. Nichols) wrote:

3% hydrogen peroxide, available very inexpensively at Wal Mart
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wrote:

Carl:
Even better brightener for removing the red stains on brass is a 50-50 mix of drugstore peroxide and saturated sodium bisulfate solution (aka "dry pool acid" mixed into warm water). Heated to about 185 F it will strip the red stuff in 10-20 minutes. It has a short half-life, so is best mixed when you need it. (the mixed solution, that is -- the bisulfate pickle will last a long time, once you add the peroxide, the mixed solution begins to degrade.)
The bisulfate pickle is relatively benign as acids go.
Regards,
Bob
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On Wed, 01 Aug 2007 19:37:45 -0700, Bob

Thank you! I have wondered for years what might brighten up brass after silverbrazing boils off the surface zinc leaving it red.
I gotta try that!
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