Etchant - least toxic + efficient

[burningman]

I'm looking for opinions on what is the safest (specifically inhalation-wise), while at the same time fastest etchant for pcb fabrication?
I've done the whole muriatic/peroxide mix with the goggles/gloves/gas safety mask - probably the least safe. So basically I'm looking for something that can be done inside relatively often and doesn't require an hour to complete a single board.
Thanks.

[MikeH]

FeCl is a bit safer, still not totally safe, but is slower than muriatic and more of a pain in term of temp, etc.  You might search for threads on electrolysis.  I seem to remember someone posting their method; I don't remember for sure, but I think it was light on the fumes (possibly free of fumes) and the liquid used was just salt water.

[orangetones]

FeCl works well for me.  Difficult in terms of temp?  Why?  I use it room temp and just aggitate the container or use a foam brush to wipe away material as it etches.  To speed things up a bit I sometimes immerse my plastic container in a warm watter bath.  Safe way to heat up the FeCl.  I also have a small PC fan hooked up to a section of white plastic dryer hose tha tI connect to my dryer vent out the side of the house for extra added measure.  But FeCl is cheap and pretty darn safe I think.

[MikeH]

FeCl works well for me.  Difficult in terms of temp?  Why?  I use it room temp and just aggitate the container or use a foam brush to wipe away material as it etches.  To speed things up a bit I sometimes immerse my plastic container in a warm watter bath.  Safe way to heat up the FeCl.  I also have a small PC fan hooked up to a section of white plastic dryer hose tha tI connect to my dryer vent out the side of the house for extra added measure.  But FeCl is cheap and pretty darn safe I think.

That's what I mean  . It's a pain compared to how I do my muriatic etches:

Put the board in the tupperware - mix the acid - pour on the acid - go watch TV, play guitar, build a ship in a bottle, etc. - take it out when it's done.

[mdh]

Nobody has mentioned the persulfate etchants.  I have been using sodium persulfate lately.  It's kind of nice that you can see the progress of the etch pretty easily, plus it doesn't stain like FeCl3.  The only downside is that once you mix it up, the solution has a limited shelf-life.  As for inhalation-safety, IIRC, the only gaseous product that is evolved from sodium persulfate is oxygen gas (and not a lot, by any stretch).  Also, you should be aware that sodium persulfate is compatible with etch resist pens (sharpies), whereas ammonium persulfate is not.

[orangetones]

That's what I mean  . It's a pain compared to how I do my muriatic etches:

Put the board in the tupperware - mix the acid - pour on the acid - go watch TV, play guitar, build a ship in a bottle, etc. - take it out when it's done.

It takes me maybe 15 minutes tops to do a large board (5x5 inch).  Yes you have to aggitate it.

As for the other comments about seeing the progress.  I use a shallow container and not very much etchant.  By aggitating side to side, you can see where it has etched fully.  I don't find it that hard to see.

FeCL stains, yes, but not the board, just things you get it on.  My solution is to work clean and not get my etchant on things that it shouldn't.