Most common used PCB etchant

[copac27]

Hello everybody,

Can you science fellows help me to find the most commons chemicals for PCB enchants (metal dissolution).

I read about aqua regia, FeCl3... but if you know something else please let me know.

 

Thank you,

[John Cuthber]

http://en.wikipedia.org/wiki/Ammonium_persulfate

 

Also, HCl/H2O2, but be careful with that as it can give off chlorine.

Edited June 28, 2013 by John Cuthber

[Enthalpy]

For a Printed Circuit Board?

 

The only one in use is iron perchloride, FeCl₃. It should be pre-warmed slightly (like 35°C) for speed, and stirred to achieve a uniform etch rate.

 

It makes horrible spots on clothes (wear an overall) but is little corrosive and harms skin not too much - though, it does etch copper, something not obvious, and doesn't etch the underlying epoxy.

 

Other mishmashes would etch copper but have drawbacks, like dissolving epoxy or the fingers.

 

Fun: with accomplices, we used 35kg or perchloride to etch away a 2kg aluminium tube that had given its shape to our graphite-epoxy tube. Aluminium let the perchloride boil so it spurted from the tube and we poured it in again. That operation was dirty for good.

[John Cuthber]

For a Printed Circuit Board?

 

The only one in use is iron perchloride, FeCl₃. It should be pre-warmed slightly (like 35°C) for speed, and stirred to achieve a uniform etch rate.

 

It makes horrible spots on clothes (wear an overall) but is little corrosive and harms skin not too much - though, it does etch copper, something not obvious, and doesn't etch the underlying epoxy.

 

Other mishmashes would etch copper but have drawbacks, like dissolving epoxy or the fingers.

 

Fun: with accomplices, we used 35kg or perchloride to etch away a 2kg aluminium tube that had given its shape to our graphite-epoxy tube. Aluminium let the perchloride boil so it spurted from the tube and we poured it in again. That operation was dirty for good.

"The only one in use is iron perchloride, FeCl3"

No it isn't.

That's why I cited two of the others.

http://www.maplin.co.uk/pcb-etch-powder-47464

Why say something that's clearly wrong?

 

And, incidentally, the name "perchloride" is so out of date that it makes "ferric chloride" seem positively cutting edge.

[Enthalpy]

Why say something that's clearly wrong?

Because I'm outdated.

[THX-1138]

FeCl₃ does quite well with copper. However, it also will attack steel. And it attacks lighter metals with exothermic vigour. Try a drop on some aluminum foil and watch. It'll start slowly showing bubbles after a few minutes, but shortly as the temperature rises a threshold will be reached and it'll go all gangsta with steam and the liberation of elemental iron.