Hi Dave, I solder rings regulary with heat sensitive stones in place.
The risk is different for each ring. It’s a combination of heat
conductivity of the metal, thickness of the shank of, distance from
the stone to the solder join, type of stone & cost of the stone. If
the ring is gold with a fine shank I will often solder it at my bench
with the head of the ring wrapped in wet tissue. {May appear a bit
risky but haven’t broken a stone yet, this way, in 22 years}. If the
ring is heavier or the stone is very heat sensitive or expensive I use
Oxy acetylene with the head of the ring immersed in water.
If the ring in my opinion is very risky to solder with the stone in
place I contact the customer & discus the risk with them.I give them
the option of continuing AT THEIR RISK! I use the following argument
with a few more words & a lot more subtlety. If they don’t want to pay
for another stone if it breaks, they would need to have it insured
against breakage whilst being worked on. I doubt there is an insurance
company who will except the risk & it would be extremely expensive. If
the work happens to be for something minor {e.g. a Resize} I point out
that for what I’m charging them & what the likely cost of insurance
would be, it is unfair to expect me to pay for replacing the stone.
I’m a jeweller not an insurance company. Most people I’ve dealt with
have no problems with this as it puts them into my shoes so to speak.
From there on the price of having a new setting edge or extra cost of
unsetting doesn’t seem half as bad.
There are times when I’ve turned work away because the risk, in my
opinion, is too high. I’d sooner have a customer upset with me for not
breaking a stone. At the end of the day I need to make a profit. If
the ratio between reward & risk is to high. It’s not worth it!
Plating on Jewellery
If I suspect a piece is plated I use a hand engraver ( Setting
lozenge ) to mark the piece somewhere it won’t be seen. Silver is
smooth to cut & plating feels gritty or may lift slightly. I have
found nitric acid handy. I use a needle file to remove the surface
layer again somewhere it won’t be seen. Place a very small amount of
nitric on the piece.
For silver : Mild reaction, white foam & blackish residue.
For plating, copper , Brass : Vigorous reaction Greenish to
Yellow.
If in doubt I contact the customer & inform them of the potential
risk of the plating bubbling or the piece discolouring.
Even after many years you still get it wrong some times.
Good Luck
Dean Watson