Backsheet thicness

Hi everyone:

My jewelry class happened to focus on the classical techniques
(granulation, fusing etc). Because there was going to be granulation
on the surface of the backsheet, we used fine silver with a thickness
of .013". I would like to do a sterling ring with a druzy cab. I have
a feeling that .013" is too thin. Is there a standard thickness for
backsheet materials when making rings? Does it depend on the size of
the cab?

The druzy is a 14X16mm rectangle. I haven’t seen any rings made from
a druzy this size/shape. Is the stone tough enough to stand up to
wear?

Thanks
Kim Starbard
http://www.kimstarbarddesigns.com

The thickness would depend on level of skill of controlling flame.
Ideally, the thinner background, the better it is since metal
granules would stiffer metal considerably, but this would depend on
many other factors. If concern is collapsing of the background
during granulation, it can be supported with fire-resisting compound.
Even regular plaster-of-Paris would work. Also, consider using
sterling for the background instead of fine silver. I am familiar
with the literature on granulation and recommendation of using fine
metals. You can obtain fine silver surface by using surface
depletion. In this way you have fine silver to work with and the
backbone of sterling to insure wearability.

As far as druzy, there is no reason to worry. A lot of antique
jewellery was set with glass paste and it still around. Properly
constructed setting is the key to stone longevity. The biggest
stresses stone is subjected to is in the process of cutting and
setting. If it survives these stages, it would do just fine in the
properly constructed ring.

Leonid Surpin

Kim; I usually use a 22 ga for backs, I have never gotten one back
due to breakage. Since drusy is kind of a generic term for a frosting
of small crystals it alone isn’t a determining factor as to
wearability. However the majority of drusy is agate- quartz which
should hold up fine under normal wear. If it is something like
uvarovite garnet or calcite you will have problems.

Dave Owen

Hello Kim,

There are drusys and there are drusys. Much depends on the mineral.
Some are more durable than others. That said, I gave my daughter
(serving as a guinea pig) a ring with a quartz drusy about 10x14mm
or so, in size. She wears it nearly every day and after a year so
far, it looks just fine. The bezel is pretty high with the idea of
protecting the edges where the crystals are exposed.

Judy in Kansas, where we are enjoying balmy temps and spring showers.
After the Cinco de Mayo show, it’s garden time!