A ring came to my bench last week for repair, the rhodium plating had
chipped (!) and left a rough, grey area exposed. Chipped plating with
funny colored metal underneath always makes me suspicious, so I
dropped some 14K testing acid on it and it turned green and bubbled.
It wasn't until I was drying it off after rinsing that I noticed the
stamp-it was ours. I tracked down the history of the ring, it was
carved, cast, set and plated on the premises. It was cast in 14Kwhite
using 24K and David Fell white alloy, alloyed on the premises.
Plating was done using rhodium solution, electrocleaner and acid dip
ordered from A+A. After emerying the chipped area prior to polishing,
I retested the gold. 14K. No reaction whatsoever. We do not nickel
plate our white gold. The ring is re-plated now, and back home with
it's owner, but the false negative green bubbly reaction has me
worried. What could cause that? Inquiring minds want to know!