I have seen clear metal prep/phosphoric acid, but a colored product would
complicate testing, as others may find differently colored solutions.

The reason I didn't mention muriatic acid (swimming pool chemical, concrete
cleaner/etcher, and good for removing rust from steel) because the muriatic
I've seen has had a dark amber color.

--
WB
..........


"N_Cook" wrote in message
...
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
.............



The PA I found as rust remover (hardware and car spares shops) probably
has
dye/colour change stuff in it, so defeating the purpose here