Wild_Bill wrote in message
...
Citric acid should be widely available, and you might want to try
phosphoric
acid if you can find a source for a small amount. Phosphoric acid is used
in
foods, but also as a diluted solution to etch and clean metals before
applying paints or other corrosion-preventive coatings. Most autobody
repair/refinishing shops will be familiar with diluted phosphoric acid as
a
preparatory step in applying primer to steel or aluminum (aluminium?)
parts.
A typical generic term here in the US is "metal prep". A paint distribuor
should have a way to get diluted PA for you, but you may have to buy a
quart
(1L sized bottle).
Diluted PA isn't particularly dangerous to handle, but it stings if it
gets
into a cut in the skin, avoid any conact with eyes.
I don't know if either of these acids would be useful for detecting lead,
or
lead-free solders.
--
Cheers,
WB
.............
"N_Cook" wrote in message
...
Just checked a day later and the SnPb boiled in vinegar for 20 seconds
plus
potassium iodide shows a slight yellow colour compared to the PbF
sample.
What other non-license source of a strong acid other than car battery
acid?
drain cleaner is clobbered by elfin safety these days.
2 days on and a more definite but pale yellow colouration , after shaking,
so a precipitate. Tin heavy sample still clear liquid. Perhaps it is just
picking up lead carbonate or something as contaminant on the surface, but
old SnPb is likely to be the only such to be found in the UK these days.
Will try boiling for 10 minutes in vinegar , i doubt you can grind down
solder in a mortar and pestle (another test maybe, perhaps high tin solder
will so grind down and not leaded version).
Will try getting phosphoric acid . Isn't there formic acid for de-calcifying
or something ?
The problem trying to get around is not post 2006 boards with PbF on the
overlay and green stickers on the casing but identifying boards like Yamaha
from 2001 or Marshall from 2003 but with PbF soldering
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://diverse.4mg.com/index.htm