I have a customer’s two tone ring which I purchased for him from
Stuller about 2 years ago. It is 18k yellow gold with a platinum
piece in the middle. (stuller item #5684). Their description is as
follows: “The 18k/platinum version uses a 18ky yellow channel sleeve
with a center insert of platinum for a bi-colored appearance only on
the outside of the band.”
I need to size it from an 10 1/2 to a 10minus.
I contacted Stuller and they said not to cut it, but then if I
shrink it, won’t it shrink differently for the two metals and
potentially leave me a mess?
I checked the archives and only found that cutting it and trying to
re-solder would cause problems with the metals reacting to the heat
and moving around.
What can I do?
Thanks for your help!
Mary Elizabeth
I have had to shrink two piece bands before. If I shrink them to the
correct size and then the center piece wants to move, I have then
shrunk the bands a bit under size and then stretched them slightly
to the desired size. This stretching up just slightly, tightens the
center piece. Two tone two piece bands of gold and platinum CAN be
sized using the laser.
This is do-able, but it’s not going to be easy. Don’t try shrinking
it, you’ll end up with a mess on your hands, or at least a lot of
extra work. You’ll have to cut it, and what’s more, I can’t see any
way you’ll avoid a sizing seam in the platinum unless you have it
laser welded. These are tricky to cut, platinum not withstanding,
because if you don’t get it right, you’ll have one part of the ring
that will close and the other with a gap. When you get the ring cut,
you’ll have to “V” out the platinum part slightly to allow enough
penetration with the laser. Once the platinum seam is filled, then
you can use gold solder to close the gold part.
Now about the cutting part. When you cut it, don’t angle the cut the
way you would usually in a sizing. Leave it more like a pair of
parallel cuts the width of the amount being removed. I mean, parallel
towards the inside of the ring. Of course they’d be parallel to each
other across the shank. You’ll then likely need to remove a little at
a time down the outer band seam until they both close, which is
better than closing them and finding you have a gap in the outer
band. Again, I’m to fussy about this stuff to try gold solder on the
platinum, since it not only looks “ghetto” it’s possible it will
eventually crack.
These rings can usually be shrunk. If the parts break free from each
other. size them sown a little smaller and stretch back up. Do this
in a slow and deliberate manner. Once cut, the band can never be
stretched again as there will never be homogenization at the welds
or solders, not to mention the unavoidable thin area.
Bruce D. Holmgrain
JA Certified Master Benchjeweler goldwerx.us
How you approach this will depend on what tooling you have
available.
If you have a stretcher/shrinker, see where on the ring the tapered
holes touch. See if you can grab just the outer gold rib, depends on
how ‘domey’ the ring is. If it contacts the insert first you might
get away with merely shrinking it since you’re only going a half
size(but can you be sure the insert is solid? If its hollow in any
way you have a problem) If it does touch just the rib, shrink the
gold portion until the platinum insert gets loose. If you’re lucky
you will be able to shrink it enough to just slip the insert off. If
you can only go so much before contacting the insert then maybe you
can slip a sawblade under the insert and saw from inside the insert.
Once you have them separated you need to calculate the required
inside diameter of the insert. Shrink the insert just a skosh
smaller, like a quarter size or so… Then shrink the gold ring
smaller til the insert can be just worked over the rib with some
effort. Now stretch the assembly to size, clinching the insert in
place.
If you need to cut the insert, the rib is in the way, isn’t it?
Rather than saw right thru the gold, saw just enough to cut thru the
insert and peel it off. Use plat hard to solder the insert back
together at the size determined above and gold solder the cuts in the
ribs. Shrink the ring as before, reassemble and stretch. The reason
not to cut right thru the ring is that a butt seam won’t be as
agreeable to stretching. Naturally its preferable not to have to fill
with solder but sometimes you can only do what you can do.
If you don’t have a stretcher/shrinker you’ll have to cut right thru
the ring, do similar to above and stretch it on a smooth polished
ring mandrel. Depending how heavy the ring is you may have to sweat
some.
That’s if you really need to retain the original look of the ring.
If you have some latitude and the customer doesn’t object to a
deviation(the seam between rib and insert will be filled with solder,
you can neaten this up to an acceptable level with a sawblade and
polishing brush) at a lower cost you could simple solder the insert
to the ring before sizing in the usual fashion. Use 20K white welding
on the platinum, 18YH on the gold and rhodium when you’re done. Not
purist but gets it done easier and cheaper.
This I know from experience will work IF the materials are suitable
to the process.
We manufacture channel bands like that one and size them regularly
by shrinking and stretching. The trick is in what tools you have on
hand to do the shrinking. The typical jewelers ring shrinker
stretcher will not do a good job easily and as some have pointed out
can make a mess. The trick is to try to apply the shrinking force on
the middle of the band not the edges. Depending on the shape of the
band and size / shape of your shrinking die you can use a standard
machine or make a tapered hole in a piece of steel so that the
shrinking force is on the middle of the band if the band is a half
round or comfort fit type profile. If it is a flat profile then it
requires a different type of shrinking tool that you cannot easily
find in the US
Don’t cut the ring. Make another .5 mm thick liner ring of the same
profile but add 2 mm to the width. This new ring should be made to
snugly fit inside the ring needing the sizing. Prior to fitting the
liner inside, file the inside edges of the band to create an area to
expand the liner into once it’s fitted.
When the liner is friction-fitted into the band, use your ring
stretcher to expand the whole works to a little smaller than the
correct size, use a ball punch to flare the 1 mm protrusions on each
edge, and then finish the edges flush and sand/polish the interior to
fit. Correct fitting of a ring is an artform in itsself, and saves a
whole lot of this kind of post-sale freebie work.