Etchants: How many are there?

[David]

^^or neutralize it with baking soda?

Uhh... yeah.      I just want to make sure I don't hear "What the heck happened to my baking soda?" or "Eeewww!  What's this MESS?"

[zjokka]

H202 as sold as hydrogen peroxide for medical use is a 3% solution. So it's 97% water. Close enough to what you use zjokka.
You could use 15% HCL and 85% H2o2 (3% solution with water) and get aproximately the same ratio.
What form do you buy the h202 in, is it a solution of water and H202?

John

The H2O2 is 38% or something, It's not for medical use at all. But now I understand your reasoning. Is that just an impression or does the HCL + H2O2 + H2O create less (violent) fumes?

Should really start experimenting with scrap aluminum.

I JUST tried etching with Hcl on a copper board! IT DOES NOT WORK !!! ARGH!! What awaste of effort
Is that why i need Peroxide?

Aluminum is much softer than copper, sorry if I caused a confusion.
For PCB: HCL (20%) + H2O2 (5%) + H2O (75%)   if the H2O2 is about 40% pure.
For Aluminum: HCL will do technically. Maybe not the most practical.

zj

[Seljer]

I admit I haven't tried, but do you get an ugly goop even from neutralising HCl? isn't the reaction only HCl + NaHCO3 -> NaCl + H2O+ CO2 ?




well anyway, I have to annouce success (of some sort) at etching an enclosure with electrolysis!

heres the setup

(I believe the coloors of my wires are wrong....if you try, there should be a bunch of bubbles coming off the negative electrode, not the object you're etching)

and here is the result of my efforts (the future enclosure for an MXR Bluebox, sorry for the language if that bothers anyone but I presume thats most people's reaction one they hear it)

I overetched it (probably left it in there for half an hour since I wasn't sure if it was deep enough :/ ) and the transfer from the transparency photocopy wasn't all that great (the toner was rather thin), it also kind of looks like the parts I touched up with a permanent marker did more harm than good
(edit: after further inspection, marker = really sucks)

but the process does work


heres another guide for it I spotted a couple of days ago http://www.instructables.com/id/EPKI62D39BEXCFGXSV/

[JimRayden]

Wow, that worked great! Looks like it's easier on the transfer than acid. And really seems to eat in.

I'm buildin myself a rig.

Just an idea: if you use a box and a copper object as cathode and anode (damn never remember which is which) and reverse the polarity, you should be able to do copper plating on the box. Then use acetone to scrub the transfer off and hope for the copper to stay on.

I'm just theorising, argue me on that one.

--------
Jimbo

[John Lyons]

I just clicked through that saltwater etch procedure linked above. That looks really promissing!!!!!!
Nothing but salt, water and electricity (as Jim said..)
I gotta try this.

John

[rockgardenlove]

I'm trying this right now...
Works great!

One thing though is that it eats through sharpie substantially more effectively than Ferric Chloride or Sodium Persulfate.  The only board that I had on hand to etch was a kind of old one that had been left overnight in FeCl₃ and it's taking off the Sharpie pretty well.

Something else that's cool is that if you collect the hydrogen gas coming off the cathode, you can make a fireball.  Sweeeet. 

[Barcode80]

toilet plumbing is ceramic, FYI. any of these solutions, with some care, can be disposed of this way.

[zjokka]

Jim, Seljer,

Cool, I really got to try this. You can just take the box out to check progress without disconnecting right?
And you can go faster and slower by varying the voltage?

Looks like the clean way to a perfect etch for aluminum boxes. You can do it indoors.
I'm kinda excited.

zj

[slacker]

I'm going to have to try this. I've been toying with the idea of etching some boxes for a while but the idea of working with and disposing of the chemicals put me off.

[Seljer]

Jim, Seljer,

Cool, I really got to try this. You can just take the box out to check progress without disconnecting right?
And you can go faster and slower by varying the voltage?

Looks like the clean way to a perfect etch for aluminum boxes. You can do it indoors.
I'm kinda excited.

zj

yep, as soon as you you take it out of the water the circuit is broken and everything stops

I believe the speed at which the process happens goes is only dependant on the current, so yes, by varying the voltage you should be able to speed this up/slow it down
http://en.wikipedia.org/wiki/Faraday%27s_law_of_electrolysis
I had it at about 1 amp, and I'd say it would have been good enough after about 10 minutes in there (I think I ended up somewhere around 25 or 30 since I wasn't sure)

though it seems the the byproduct of this process (which if I analyzed this right, is greyish aluminium oxide) is really hard to get out of the engraved areas (or maybe its because I left it in there too long...I've got another box I plan on doing today or tommorow)

[rockgardenlove]

Has anybody tried this with a circuit board yet?  It didn't end up working so great.  I might take another shot at it if somebody else reports success. 

[birt]

i'm definatly gonna try electrolysis. seljer, the grey you see in the bigger traces is just the aluminium. in small traces it is very rough and will appear to be quite dark but in big traces it's not rough anymore so it appears to be lighter. when i etched zinc in art school i had the same effect.

there is a solution to this tough. if there are bigger areas to be etched, you blow the dust of some kind of wax on those areas and melt it on there. it's covered with small wax bumps then that will prevent the etching on those spots making it a very rough surface.

there are more cool techniques. there's the old way of covering the whole box with temperature sensitive laqcuer (this is specially made for etching, there's also etching laqcuer that's just liquid and you paint it on the box) and scratching a drawing in that. then etch.

you can also mix sugar and inc, paint the drawing with a very small brush and let dry. then cover the box with liquid etching laqcuer and let dry. if you put it in warm water now the laqcuer will come off where you've drawn with the sugar. then etch it.

the heat sensitive laqcuer is cool for all kinds of textures. when it's a little warm you can push cloth or leaves or whatever structure in it and you can etch the marks.

[zjokka]

I etched a Hammond box with diluted HCL this afternoon.

Last time I used the pure stuff and that worked great, but created a lot of disgusting fumes which you cannot avoid. You have to check the box regularly for progress. This time I diluted 75% water and 25% HCL wich started bubbling right away but I didn't notice any progress even after 4-5min.

When I had etched with HCL + H2O2 the result I remembered, was dark discoloration of the bare areas, but now they remained shinily polished, or so it seemed. After a while I panicked and added a bit H2O2 because I thought things weren't getting on.

Finally I took the box inside to rinse it in the sink and check against the light. Of course it had etched alright! It's just that the discorolation on the etched out areas only appears when you DRY the box with this method ??

anyway I didn't overetch -- as much ;-)

but still a ripoff!



zj

[John Lyons]

that looks pretty good zjokka. There is a little blotching around the DU and volume but otherwise I'd say it was fine.
Why don't you link it?

John

[zjokka]

That blotching was toner I lost and touched up with marker. It doesn't work, a better way is to put some paint on with a fine brush which is scraped off where you might touch the lettering.

Why don't you link it?
John

What do you mean 'link it'? 

zj

[markm]

that looks pretty good zjokka. There is a little blotching around the DU and volume but otherwise I'd say it was fine.
Why don't you link it?

John

That does look good indeed.
It's gotta be one of the best electro-etches I've seen.
I'm still more comfortable with FeCl etching despite the chemical thing but, you guys certainly are making some progress with this method.
Markers such as Sharpies really don't work all that well IMHO.

PNP with a paint mask and shallower etching can provide great detail if you take your time and don't leave it in too long!