Chemicals for enclosure etching

[xorophone]

Hello! I've decided I want to try some enclosure etching soon. For etching circuit boards I've been using hydrochloric acid mixed with hydrogen peroxide. Will this solution work for enclosure etching too? And do I need to mix a fresh batch or will the old one with dissolved copper work?

If this won't work, what do you recommend? I've seen most people use ferric chloride, but that's really hard to get ahold of here. How about sodium persulfate? Or ammonium persulfate? Preferably sodium persulfate out of those two.

Sorry if this has been asked a thousand times before. Thanks for the help!

[greaser_au]

A mixture of copper suphate and table/rock salt is an alternative (but I haven't tried it so I can't say how well it works yet)...

david

[akalabeth]

Hi there,

I used toner transfer and caustic soda for the etching. Part of the process is documented on my blog: https://www.viniciusrezende.com.br/2017/02/build-report-swollen-pickle-modified-big-muff-pi/
It was the first time I did it and I didn't protect the area well, nail polish is an option. However, I recall reading somewhere that caustic soda eats nail polish.
Oh, a toothbrush really helps too.
After talking to a fella here in Brazil, he advised me to try with photoresist ink and ferric chloride (fresh one) next time.

My advice for you: read a lot. do some small-scale tests with all the methods you find.

[Lizard King]

I use muratic acid - swimming pool supply store - and hydrogen peroxide.  2:3

Works great.  Neutralize acid with baking soda when finished.

[xorophone]

I use muratic acid - swimming pool supply store - and hydrogen peroxide.  2:3

Works great.  Neutralize acid with baking soda when finished.

Great! From my knowledge muriatic acid is pretty much the same thing as hydrochloric (which is what I've been using for circuit boards). How diluted is your hydrogen peroxide and muriatic acid by the way?

[Lizard King]

Great! From my knowledge muriatic acid is pretty much the same thing as hydrochloric (which is what I've been using for circuit boards). How diluted is your hydrogen peroxide and muriatic acid by the way?

I'll have to look tonight at my acid jug.  The hydrogen peroxide is what you pick up at WalGreen for first aid type uses.

(I used to have a link to a VERY detailed article on how to etch.  That's where I got the acid/peroxide tip - along with several others.  I can't find the link but I'll look some more after work.)

[xorophone]

Great! From my knowledge muriatic acid is pretty much the same thing as hydrochloric (which is what I've been using for circuit boards). How diluted is your hydrogen peroxide and muriatic acid by the way?

I'll have to look tonight at my acid jug.  The hydrogen peroxide is what you pick up at WalGreen for first aid type uses.

(I used to have a link to a VERY detailed article on how to etch.  That's where I got the acid/peroxide tip - along with several others.  I can't find the link but I'll look some more after work.)

I've been using 30% hydrochloric acid and 3% hydrogen peroxide. Works just fine. Just wanted to make sure the measurements are correct.

Would love to read that article if you can find it!

[GiovannyS10]

For me ferric chloride + photosensitive paint works so well 

[deadlyshart]

Aluminum is luckily relatively easy to etch, actually. I've always used ferric chloride, but hydrochloric acid (muriatic, etc) should be a pretty similar mechanism, I believe. That is, the FeCl3 basically creates HCl in a sense ( http://www.artmondo.net/printworks/articles/ferric.htm ).

I'm sure it works very well, but I'd be very wary of mixing oxidizers like HCl + hydrogen peroxide. Obviously acid on its own can produce lots of heat, but the two of them can get pretty carried away (for example, in a lab setting I've used piranha etch, which is similar, a mix of sulfuric acid and H2O2: very dangerous).

The other route is using bases. I know a lot of people here swear by NaOH (and I'd assume others like KOH work). I've never tried them though.

[antonis]

An alternative proposal is the use of a Dremel-like tool with the proper grinding bit..

For small to medium surfaces (i.e. 3 pots & 1 switch) it takes less time than etching procedure, it's safer and has more fun...