Just a note about agitation...
I used to use an aquarium aerator and an air stone for agitation. It
had two problems. First, sometimes the bubbles stuck to the copper.
This was a minor problem.
Second, though, it tends to aerosolize the etchant. After a ver few
boards, I realized that the heads of all nails in my storage closet had
been etched away.
Get a small aquarium water pump. The pump moter is very well sealed in
plastic and drives the impeller with a magnet. No bubbles, no aerosol.
Salt water is corrosive and any metals dissolved in a saltwater aquarium
become toxic, so they are pretty careful to avoid anything that will
corrode.
Thanks for the info on the etchant. It appears that this method is
superior to both FeCL and ammonium persulfate (or is it perchlorate)?
Never can remember, one etches, the other makes rocket fuel :)
On 06/10/2010 09:06 AM, Mark Lerman wrote:
> I don't make a lot of boards, and most of them are quite small, so
> I've been looking for a simple, fast way to etch. After experimenting
> with a few suggested recipes, I use a 1:1 ratio of muriatic acid
> (31.45%) to 12% hydrogen peroxide. The muriatic acid is available in
> any hardware store, the peroxide is easily obtained from a beauty
> supply store as "40 volume developer" - get the clear, not the creme.
> They are both very inexpensive, and the etching takes 1-2 minutes
> with a little hand agitation, no bubbling, no heat. DO THIS OUTDOORS
> or with a chemical hood. Then use NaOH to neutralize.
>
> For an etching container I use a polypropylene storage bin - they
> sell them is many sizes and they are very inexpensive.
>
> Mark
>
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