Reuseable etchant woohoo!

[John Lyons]

I learned something today. (thanks juse!)
I have been using muratic acid (30ish%)  and hydrogen peroxide (3%) for a year or so now.
I figured that it pooped out after a while so i was dumping it after each use.

A forum member turned me on to this link. I don't think it's been posted here so far (has it?)
http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/?ALLSTEPS
Cut and paste this into your browser address bar.

Works well, fast, re-useable dirt cheap compared to Ferric cloride.

Thanks juse once again.

John

[GREEN FUZ]

ERROR 404: Not Found

[mikengstrom]

try the this one 

http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/?ALLSTEPS

[GREEN FUZ]

That`s it.

[Papa_lazerous]

ow that interests me, will have to try it!

[MikeH]

I've never been able to re-use my muriatic; it seems to be really weak afterward and doesn't work fast enough, and the traces always get undercut.  Instead I etch in a really small container and only make enough to barely submerge the pcb.  Even if you toss it after every use, it still is cheaper and works better than ferric.

[GravityRobert]

Interesting, I think my dad has a small stock of the pool acid 

[jakenold]

That looks really neat! But as I do my stuff in the small kitchen of my appartment, I need something that doesn't stain and isn't toxic in anyway. That pretty much leaves me with electrolysis, which I find is really simple and easy - and fun to watch 

I keep a small tank of natrium persulfate to etch the tiny amount of remaining copper of the boards, after the connection breaks by the electrolysis. I can reuse the same solution like a hundred times before I need to make a new one. That how I roll!

Jake

[burningman]

I use the hydrochloric (muriatic)/peroxide mix and it works very fast. I only do small boards and use a small plastic container, sometimes agitating the mix. I would definitely recommend wearing goggles, proper gloves and a 'AOsafety' chemical respirator (made spec. for muriatic acid) and conducting all of this outside. I have a couple of questions.
Does anyone know:

• If this stuff freezes over winter (i've left it outside unmixed) and whether freezing would lessen its effect after dethawing in the spring?
• How does everyone dispose of this stuff? I got PH paper and could getting baking soda to neutralize but I've never done this before

Cheers.

[MR COFFEE]

@MikeH,

Throwing away the solution is bad for living things because the copper salts are HIGHLY toxic.

[Hamfist]

I started using the muriatic acid/peroxide mix recently.  Works waaaaay better than FeCl, IMO. 

And FYI, the first time I used it was on the porch in 20 degree weather.  Worked fine.  Slower than room temperature, but it still worked.

[Cardboard Tube Samurai]

I just use ammonium persulphate. I get heaps of etches out of a batch/mix. I have been told it's relatively harmless when it can no longer etch though I am still reluctant to just throw it away. I'm waiting for the next free chemical disposal day the local Council has

[juse]

I've never been able to re-use my muriatic; it seems to be really weak afterward and doesn't work fast enough, and the traces always get undercut.  Instead I etch in a really small container and only make enough to barely submerge the pcb.  Even if you toss it after every use, it still is cheaper and works better than ferric.

What percent muriatic are you using & what is your mixture ratio with the peroxide?

[earthtonesaudio]

Totally cool. 
Captain Planet would be proud. 

[bean]

Can anyone tell me if there is an advantage to heating the muriatic acid solution over room temperature? Or is the etch time pretty much the same...?

[John Lyons]

As far as I can tell there is no benefit to heating the Hcl/H2o2 etchant.
My basement shop ranges from 35 to 75 degrees thoughout the year and the etching time is the same.
I seem to remember that heating this particular solution is a BAD thing as it will react badly...I forget how.
For a mid sized board with 1 oz thick copper it usually take 5 minutes or less.

John

[bean]

Right on. One fewer step to completion! Thanks!

[cpnyc23]

i'd be interested to know how you go about disposing of a batch that is filled with spent copper.

Seems like it would be really toxic after a dozen uses or so....

-chris

[darron]

i'd be interested to know how you go about disposing of a batch that is filled with spent copper.

Seems like it would be really toxic after a dozen uses or so....

-chris

well apparently it's supposed to last you a lifetime, so you can do the x1000 etches (: you'd imagine that you'd want a bit of mix to do that though?

looks really cool. i'd be interested in mixing a batch. alright, i'm a bit surprised that nobody has asked. what about the aluminium enclosures? in theory i suppose i only do a few more boxes than i do circuit boards, so i could use the mix for both. any experience etching the enclosures?

thanks (:

[earthtonesaudio]

I am fuzzy on the chemistry, but it looks like etching aluminum enclosures would work fine, but you might be diluting the cupric chloride with aluminum.  My guess is that might increase the etching time, and at worst you'd have to throw it out and start over. 

But I'd say go ahead and try it with a small amount, and then go back and etch some copper and see what happens.