I was wondering if anybody could explain this. After reticulation
process and pickling in weak sulphric acid, I polished some parts of
a ring and to get rid of the dust washed it under water with soap and
rinsed it. after a day or so there formed a green surface on the ring
that I removed with another short pickling. I wondererd what had
happened? Greetings from far Germany,
Michael
What metal were you reticulating. If it was silver the green
discoloration will be a copper salt. I don’t think it’s got anything
to do with the soap but with the acid you used to pickle the metal in.
Somehow it’s managed to seep into the silver and combine with the
copper. I suspect that the surface has become porous through
overheating. Next time you clean and pickle it immerse the article in
hot neutralizing solution and leave it there. Sodium bicarbonate
should do it and leaves a residue of sodium sulphate which is soluble.
Tony Konrath
Gold and Stone
tony@goldandstone.com
www.goldandstone.com
After reticulation process and pickling in weak sulphric acid.... washed it > under water with soap and rinsed it. after a day or so there formed a green surface on the ring
G’day Michael; Soap contains sodium stearate, made from a fatty
acid, and although soap is mildly alkaline, a very thin film left on
sterling soon deteriorates back to the fatty acid. This combines with
the copper in sterling to produce copper stearate which is green.
Further pickling would remove copper stearate. Good brushing in warm
water would eliminate this completely.
NOW! I suggest this as something that could possibly occur, but
freely admit that this explanation is but a guess on my part, for I
have not seen anything like this in the books and have not experienced
it. But many people will have witnessed the green colour that can
occur around copper exposed to soap and water, say in a bathroom.
Plausible, no? Oh well… But cheers anyway
John Burgess; @John_Burgess2 of (further away!) Mapua Nelson NZ
<< Sodium bicarbonate >> … that’s ‘arm&hammer’ baking soda - brought
to us by armand hunt & brother - you remember, the first texans who
tried to shoot the moon for all of the silver in the world awhile
back & raised the price skyward & beyond. (are we EVER going to be
free of texans!?!)
a little true humor -
ive
<< Sodium bicarbonate >> ... that's 'arm&hammer' baking soda - brought to us by armand hunt & brother - you remember, the first texans who tried to shoot the moon for all of the silver in the world awhile back & raised the price skyward & beyond
If you mean William Herbert and Nelson Bunker Hunt, you can follow
this link to their attempt to corner the silver market.
http://www.buyandhold.com/bh/en/education/history/2000/hunt_bros.html
No relation at all the famed industrialist, trader and art collector
Armand Hammer. Who one might also add is unrelated to the baking
soda company.