Homebrew PCBs

Philip Pemberton wrote:
> Hi guys.
> 
> I just dumped the contents of my 2-litre concertina bottle of FeCl3 into 
> my etching tank, and about half way through I was treated to a loud 
> HISSSSS as this lot got dumped in the funnel:
> 
> http://groups.yahoo.com/group/Homebrew_PCBs/photos/album/338698001/pic/1053817307/view
> 
> Basically, it's a dark brown precipitate that's formed into round loops, 
> not unlike dead leaves in autumn. I now have the unenviable job of 
> dismantling the tank and cleaning out the base and the air bubbler. One 
> of these days I'll rig up a proper circulation pump and filter system 
> (not unlike those on photo-lab machines if you've ever seen inside one 
> of those)...
> 
> But anyway, back to the subject of my question. Does anyone know what 
> this stuff is? My FeCl3 is a somewhat greenish brown at this point, but 
> I've got a 5-litre bottle of "hyper-activated" FeCl3 in the garage. 
> Would there be any benefit to adding a bit more concentrate to the 
> working tank?
> 
> And the final question: how the hell do I get rid of this stuff? Flush 
> it down the loo? Double-bag it and chuck it in the bin? Call a local 
> haz-chem company who won't touch it until I've got some arbitrary number 
> of litres of the stuff and am willing to pay several hundred quid in 
> disposal fees?

See if HCl dissolves it. If so, you can keep using it as etchant.
If you have a bubbler to agitate the tank when etching, things will
get much easier.