Chemical test for SnPb lead/ RoHS lead-free solder
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From: N_Cook on 8 Mar 2010 06:04 A chemist gave me enough potassium chromate to have a go. Ground off a few mg from some sheet lead , dropped into some chromate solution and a cloudy yellowish deposit formed in the otherwise orange liquid - what it is supposed to do apparently. Then ground off some known lead free solder , added to some of the solution and no yellow. Then ground off some known SnPb solder and again no yellow - so not so simple a test as first appeared, Pb and tin are combined too well to react ?
From: D Yuniskis on 8 Mar 2010 12:11 N_Cook wrote: > A chemist gave me enough potassium chromate to have a go. Ground off a few > mg from some sheet lead , dropped into some chromate solution and a cloudy > yellowish deposit formed in the otherwise orange liquid - what it is > supposed to do apparently. > Then ground off some known lead free solder , added to some of the solution > and no yellow. > Then ground off some known SnPb solder and again no yellow - so not so > simple a test as first appeared, Pb and tin are combined too well to react ? Why not try one of those inexpensive "sticks" used to test for lead in paint? (no idea if it would work)
From: Arfa Daily on 8 Mar 2010 18:13 "N_Cook" <diverse(a)tcp.co.uk> wrote in message news:hn2lj4$ond$1(a)news.eternal-september.org... >A chemist gave me enough potassium chromate to have a go. Ground off a few > mg from some sheet lead , dropped into some chromate solution and a cloudy > yellowish deposit formed in the otherwise orange liquid - what it is > supposed to do apparently. > Then ground off some known lead free solder , added to some of the > solution > and no yellow. > Then ground off some known SnPb solder and again no yellow - so not so > simple a test as first appeared, Pb and tin are combined too well to react > ? > > Well, we all knew that SnPb solder was a stable compound that was not going to break down on its own, allowing cartloads of lead to somehow get into into the environment, as the eco-bollox lead-free solder brigade, would have us believe ... Arfa
From: N_Cook on 9 Mar 2010 03:24 Arfa Daily <arfa.daily(a)ntlworld.com> wrote in message news:Zwfln.241303$Np2.139437(a)newsfe24.ams2... > > "N_Cook" <diverse(a)tcp.co.uk> wrote in message > news:hn2lj4$ond$1(a)news.eternal-september.org... > >A chemist gave me enough potassium chromate to have a go. Ground off a few > > mg from some sheet lead , dropped into some chromate solution and a cloudy > > yellowish deposit formed in the otherwise orange liquid - what it is > > supposed to do apparently. > > Then ground off some known lead free solder , added to some of the > > solution > > and no yellow. > > Then ground off some known SnPb solder and again no yellow - so not so > > simple a test as first appeared, Pb and tin are combined too well to react > > ? > > > > > > Well, we all knew that SnPb solder was a stable compound that was not going > to break down on its own, allowing cartloads of lead to somehow get into > into the environment, as the eco-bollox lead-free solder brigade, would have > us believe ... > > Arfa > > That was what I was thinking. And it wold take more than acid rain to leech the lead from solder, or lead would not be possible to be used as the plates in car batteries. The only "lead" test pens I've seen are in paints section of hardware and at 8 GBP a pop and nothing on the package about being used on more than one occassion, they can stay on the shelves. Those would be for red lead in paints, which is not elemental lead, so probably would not work either
From: Arfa Daily on 10 Mar 2010 12:53
"N_Cook" <diverse(a)tcp.co.uk> wrote in message news:hn50n6$ni2$1(a)news.eternal-september.org... > Arfa Daily <arfa.daily(a)ntlworld.com> wrote in message > news:Zwfln.241303$Np2.139437(a)newsfe24.ams2... >> >> "N_Cook" <diverse(a)tcp.co.uk> wrote in message >> news:hn2lj4$ond$1(a)news.eternal-september.org... >> >A chemist gave me enough potassium chromate to have a go. Ground off a > few >> > mg from some sheet lead , dropped into some chromate solution and a > cloudy >> > yellowish deposit formed in the otherwise orange liquid - what it is >> > supposed to do apparently. >> > Then ground off some known lead free solder , added to some of the >> > solution >> > and no yellow. >> > Then ground off some known SnPb solder and again no yellow - so not so >> > simple a test as first appeared, Pb and tin are combined too well to > react >> > ? >> > >> > >> >> Well, we all knew that SnPb solder was a stable compound that was not > going >> to break down on its own, allowing cartloads of lead to somehow get into >> into the environment, as the eco-bollox lead-free solder brigade, would > have >> us believe ... >> >> Arfa >> >> > > > That was what I was thinking. And it wold take more than acid rain to > leech > the lead from solder, or lead would not be possible to be used as the > plates > in car batteries. Or of course as lead flashing on every house ever built, or lead guttering, as is found on many old - and even ancient - buildings, and has been there for hundreds of years, being 'dissolved away' (ha!) by the rain for all that time, including the several decades of bad-arsed acid rain, that we had in the last century ... Arfa |