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Ring shrinkage and sizes


#1

Hi there!

Ran into another problem I wish somebody could help me with…

This is my first full collection, which I plan to try to sell to
galleries and stores.

I just started to think about ring sizes. my rings are
unconventionalare and not easy to resize.

Therefore I think it would be best to create a mold for each size
(say, 6, 7 and 8) so I don’t have to resize it each time.

As I am creating my rings from wax, they shrinks about 5% after
making the first mold from the model and will shrink another 5%
after making the second mold (after resizing).

Problem is, the model (the one I resize from), say it is a size 8,
is proportionally bigger than the other sizes (lets say there is a
flower on the ring, so the flower is bigger in this one ring than in
the other rings after resize, because that second mold shrinked it).
Is this normal / acceptable, or do I need to shrink this one also,
so the flower on the ring will be the same size as the 6 and 7 size
rings?

Hope I explained myself properly… It comes down to this: is it
"normal" that one ring size will have a bigger flower than all the
other sizes, or do I need to shrink this first model I resized from
again, even though there is no reason to do it except for the
different flower sizes?

Thanks in advance,
Sincerely,
Jonathan


#2

Hell Jonathan: this sounds like a production modeling question which
I have been doing for the last 30 years.

Here’s what you need to do; make an RTV mold of your original wax or
model or your first ring that you’ve fabricated, then shoot waxes
from that mold and size the waxes in wax, the size 6 needs to be a
6,1/2; the 7 needs to be 7,2/3; the 8 needs to be 8,3/4, then make
your models of these sizes with a minimum of wear. The sizes will
come out perfect for the first generation after molding. the reason
that you want to make the RTV mold is because you don’t want the top
to change or go through several generations of shrinkage…

Frankenstein


#3

Jonathan:

As long as the flower is the same size on all your various masters,
it should be roughly the same size on the end products. The shrinkage
will be roughly similar for each master.

This is assuming that you’re making up new masters for each size,
rather than using a bunch of cycles of molding/casting(shrinking)/
remolding(more shrinking) to generate progressively smaller end
pieces.

Regards,
Brian.