thinking about switching to sodium persulfate (from ferric)

[kato]

Will sodium persulfate etch aluminum too?, like ferric chloride does?
I can't find that info anywhere online.

 

[gyraf]

a quick googling on ["ammonium persulfate" aluminum] shows e.g. a patent for removing copper from aluminum foil.

 

[kato]

Don't think I didn't do that search. But I'm not looking to "remove copper from aluminum foil." I'm looking to etch down a chunk of aluminum (to a smaller chunk). Also, I asked about Sodium Persulfate, not Ammonium Persulfate.

I'd just like to hear some actual experience before committing $23 for a litre.

 

[gyraf]

aah sorry - I thought you wanted to avoid damaging some aluminum, and that you ment ammonium persulfate (because this is the most common sub for ferric chloride in pcb-making)...

 

[peterc]

Check the Stompbox forums, I remember someone there trying to etch an aluminium box using Sodium Persulphate with not good results......

My memory is hazy, cant remember the exact details.

Peter

 

[pyjaman]

hi, this thing work well on aluminium:
http://www.instructables.com/id/Stop-using-Ferric-Chloride-etchant!--A-better-etc/

Laurent.

 

[Jarno]

Etching die-cast enclosures with persulfate will not work, you have to use either Ferric or peroxide/ hydrochloric. I use the latter since the reaction also works at room temperature, and below. So I can put the bowl outside in wintertime and etch PCB's and enclosures without the added hassle of adding boiling water to the "au-bain marie".
You will need to do it outside BTW, because the fumes are pretty awful (and dangerous).
The drawback is that etching with peroxide is "rougher" than the other two methods, it creeps under the etch resist and the reaction is pretty violent, keep a close watch, especially with thin tracks on PCB's.

 

[pyjaman]

Yes, it can become quite rough and barely "incontrolable" but the solution neutralize by itself with use and time. I have an entire bottle of this "dead" solution I keep, and "awake" it when I need it by oxygenizing it with an air pump for aquarium. This way I obtain a  very "gentle" etch.

Laurent.