Learned new trick with vinegar - peracetic acid

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.

--Got some weights/volumes to add to this hack?

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

Two parts peroxide to one part muriatic by volume. It's not fussy.

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

[ ... ]

*Which* peroxide? Hydrogen peroxide? That's the most common one, but it could be some other.

Enjoy, DoN.

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:

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 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)

According to Carl Ijames :

Thanks for this -- and all that I snipped below.

Enjoy, DoN.

3% hydrogen peroxide, available very inexpensively at Wal Mart

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!

Interesting. I didn't know there was another web page about this. Here is mine for comparison:

Not based on my own work, but from a book long out of print.