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10K & 14K pink rose solder color mismatch


#1

Hi,

We are facing problem of the mismatch of color of pink gold casted
alloy and the pink/rose gold solder. We do not get the color of the
pink solder same as the parent casted alloy. This creates a yellowish
patch on the jewelry piece. Is this a common thing noticed by others
too ? OR am I doing something wrong.

The solder that does have some closer color match is too hard and
does not work properly.

Any help/advise/suggestions in this regard is highly appreciated.

Best Regards,
Dinesh


#2

Dear Dinesh,

The karatage & colour are related to alloying procedures. Quenching
is critical. Pickling baths are another factor to look at. Your seams
donot match up. Your methods of soldering have also to be looked
into. Are you using UPMR or Legor alloys.

Give more details,
I can trouble shoot.

Warm regards
Umesh
Mumbai.


#3

10 kt. will obviously have more copper than 14 kt, and 14 kt. has
enough copper by weight to not only provide the appropriate flow
point but as a colourant too. When fabricating one’s own solders
matching the colours of vendor’s raw materials is only 99.9%(+/-)
accurate with XRF analysis if the manufacturer will not give you the
exact copper content of their metal- a call to the tech support line
of your vendor would be telling. Even fire assay results you perform
in your studio may be off just enough to effect the colour that
results from fabricating your own solder in attempt to match their
metals. A quick shot of an XRF meter (a friend with a gold /metals
buying operation or a jeweller would probably do this for you at
little if any cost as it takes perhaps 2 seconds of their time).will
yield accurate composition of both solder and raw materials so you
can compare the figure and correct any deviances so both formulae are
an exact match.

If you are buying solder and raw materials from different vendors
you will always get different colours. If you fabricate your own
products you must take care to figure all the elements of the
formulas and the multiples indicated by the weight that you wish as
the outcome. Often it is not simply adding “x” percent of Cu three
times to get 2/3 more of the original quantity of solder or raw
material.

To make the solder softer look at the amounts of Zn, cadmium and/or
tin if included in your recipes and increase the Zinc to the limit of
it’s tolerance in the formulae- i. e. if the weight of Zn per 1 gm of
med.

solder is *.*12, you can’t multiply.12 x 10 and presume you are
adding the correct weight of zinc for 10 grams yield, as the range
(on a gram scale) between.12 and.13 makes a huge difference in the
colour that will result in the entire quantity yielded. It is
important to be accurate for both the flow point (temper) of the
solder as well as the colour you want to result. Also once you
achieve the result you desire, it is crucial to write it down to
duplicate the result in the future! Zinc, tin and even bismuth will
increase the flow in “hard” solders, but the type of soldering has to
be considered. If not torch soldering, and using a high intensity
iron for production type joining, paste formulas that flow at lower
temperatures may be the way to go, but on the other hand permanence
of the join, the kind of flux and pickle used and finishing all bear
on the decision you make. There are a few companies that produce fine
pastes in a wide range of flow points including med. hard and med.
soft, as well as i believe 4 flow points in the “easy” range that are
still strong enough for bonding gold. however the company doesn’t
formulate a rose/pink gold colour- that would have to be a custom
order. If you need a contact at that company dfeel free to contact me
off list… rer Often with gold solders