Philip Pemberton wrote: >=20 > In message <003001c49942$bce48280$0d401545@whythis> > "Denny Esterline" wrote: >=20 > > I started mine about a year ago using HCl and H2O2 (hydrochloric acid= - > > branded Muratic acid - 32% strength, and 3% medical grade hydrogen > > peroxide) Both are available locally, HCl about $4 US per gallon and = H2O2 > > less than $1 per quart. I used two parts H2O2 and one part HCl and go= t a > > fairly aggressive etchant (about 4 minutes) and yes, it produced nast= y > > Chlorine fumes. >=20 > Hardly surprising. That's a "piranha mix". I'd be VERY surprised if you > managed to make CuCl etchant out of it - it degrades pretty quickly. > How did you convert it into CuCl? Just dump a load of copper into it to= get > rid of the free chlorine? ok, that makes more sense. i new there was a process where keeping the ration of peroxide to hcl was critical and sometimes difficult during production runs. and it sounded like there were 2 different but similar things going on here. =20 -------- > No easy way to get chemicals in the UK - you need to work for a company= that > has a reason (and a damn good one) to require the chemicals, fill out v= arious > forms, etc. > I've heard of people ordering chemicals, then ending up telling the loc= al > police what they wanted them for. From what I've heard they catch a lot= of > amateur pyrotechnicians (?) that way... ------------ that's terribly unfortunate. in the u.s. any company can get nearly any chemical, mind you that they do pay some attention and if you are obviously ordering things to make drugs or explosives you will have some explaining to do. also unfortunate that they go after amateur pyrotechicians. that's one of the things that got me and a lot of people interested in chemistry, and here in the u.s., at least in some states, it's perfectly legal and i know of a company that specializes in the necessary supplies and books. i've seriously considered getting back into it (i'm in wyoming, plenty of open space and when it's damp there isn't a fire hazard, though there would be during much of the year). this paranoia really doesn't accomplish much in the way of preventing problems but it does do a lot of harm in not letting people get interested in this stuff and science in general after a while. all the real science geeks i know who know anything about chemistry started with fireworks, however primitive, and most went on to know far more than just how fireworks work. but that's just my humble opinion, but i've seen motivated people get whatever they want, sometimes it encourages theft which is very unfortunate. i have the remains of several chemistry sets in my garage, and the small quantities of chemicals and chemicals i've purchased, i love chemistry. for what it's worth, i'd actually like to see a lot more police than we have here, and i'd like to see them better trained so they might be friends to more communities rather than all too often being seen as another problem.=20 i've met some good cops, and some bad ones. --=20 Philip Stortz--"In Germany they came first for the Communists, and I didn't speak up because I wasn't a Communist.=20 Then they came for the Jews, and I didn't speak up because I wasn't a Jew.=20 Then they came for the trade unionists, and I didn't speak up because I wasn't a trade unionist.=20 Then they came for the Catholics, and I didn't speak up because I was a Protestant.=20 Then they came for me, and by that time no one was left to speak up." -- Martin Niem=F6ller, 1892-1984 (German Lutheran Pastor), on the Nazi Holocaust, Congressional Record 14th October 1968 p31636. _______________________________________________ http://www.piclist.com View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist