Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

If you must use FeCl, don't get the pellets or powder. Its
exothermic (I think this is the right term) when it reacts with water
and produces a lot of heat and splashing if you aren't careful.
Makes a gawdawful mess. Nasty stuff.

I agree with Stefan, CuCl is a better way to go (cheap, easy
availability of components). Even Ammonium Persulfate is better than
FeCl (no staining and doesn't generate heat when mixed with water)
though relatively pricey.