Pewter Jump Rings

A customer asked me to mill series of flat, disk shaped pendants an
inch in diameter and about 3 millimeters thick, with recessed areas.
The models will be cast in pewter and detailed with enamel.

A “U” shaped jump ring as thick as the pendant was specified for
purposes of strength and durability.

I suggested that a traditional round jump ring, about 2 mm thick,
slightly embedded into the disk, would probably be adequate in terms
of strength.

Not being extremely familiar with casting in pewter, I have what
seems like a very basic question.

Are there any pros or cons to using a “U” shape jump ring as opposed
to a round one, and must it be very thickly proportioned, or would it
be more of a stylistic choice?

Thanks,

Jesse
http://jdkjewelry3d.ganoksin.com/blogs/

Hi Jesse,

2mm should be adequate but 3 would be better if the client doens’t
want to see returns based on breakage. A U shaped jump ring will be
stronger is it’s parrallel to the piece instead of a round one just
because the legs are farther apart adding stability. Either would
work fine though. A round profile on the bale is easier to pull out
of the mold especially if the it is oriented perpindicular to the
piece. Rubbers used in white metal casting are more rigid than those
used in lost wax casting so they will last longer if you make sure
there’s no undercuts and a slight draft on any vertical walls etc.

Harry Hamill
www.harryhamilldesigns.com