Thanks for your help everyone. I tried it today. Unfortunately it
wasn't very successful -- it took about 10 minutes to etch, slower
than the ammonium persulfate I usually use. Having to do it outside (I
don't really want to mess with acids of that strength indoors with
only a window for ventilation) meant it was much colder than room
temp... whether that was the reason or not for the slow etch, I'm not
sure.
Either way, I think I may take the advice of the person below and
obtain a small etching tank with a heater, probably safer for the
small volumes I do, and in actuality even heating up the etchant in a
bowl of hot water is probably less inconvenient than having to move
everything outside :)
I much appreciate all the advice, perhaps I'll try it again sometime
when the weather is warmer! :)
> Etching tanks like below (ET-10) do quite well on a small scale using
> an aquarium heater and air pump;
>
> http://www.pbase.com/eldata/image/62352752
>
> Compact, cheap and easy to use.