William "Chops" Westfield mac.com> writes: > > I can honestly say I've never smelled chlorine whilst etching As you may have read in the pdf document linked by me before, FeCl3 etches by releasing Cl ions into the solution. It is very likely that the presence of some impurites can cause HCl and other toxic chemicals to be released into the air bubbles that percolate through the solution. The FeCl3 bath has a peculiar characteristic smell, but that is not the smell of chlorine. Adding certain chemicals to the bath while trying to neutralize it can produce really bad fumes, however. Peter -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist