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Casting a bracelet


#1

While I am primarily a bead weaver, I do some silver work as an
adjunct to the beading.

One of my “production” items is a cuff bracelet featuring a wide,
flat strip of woven beadwork, very intricate design.

The cuff itself is simple: imagine a 6" x 1" strip of 20 gauge
sterling with a frame of 2mm square sterling wire soldered around the
perimeter on top of the flat strip. The beadwork is set into the
"frame" after the bracelet is shaped on a mandrel.

While the smithing isn’t complex, it seems to me that I could save a
lot of time by having the bracelet cast. I made a model in silver,
sent it to a local casting house. I asked for a silicone mold, as I
understood that it would have less shrinkage, and I asked for fine
silver so there’d be less tarnish (it’s not easy to clean the bracelet
once the beadwork is set in). I wanted 5 castings of the bracelet.

Bottom line: the caster couldn’t produce more than 2 decent casts in
the three weeks he had the work. I finally just told him to send the
master back to me. And now I’m still fabricating these cuffs, over and
over again…

Orchidians, what did I do wrong? Is my design intrinsically
un-castable? In casting companies’ ads, I see pictures of bracelets
that appear similar in volume and general design (without the beading
of course). Was it the request for fine silver? Now I understand that
there’s a low-tarnish sterling…would that have been easier to cast?
Should I not have requested a silicone mold? How do I adapt my master
bracelet to accommodate shrinkage? Is shrinkage uniform in all
dimensions?

Help!

Amy Karash
Fine Craft BeadWork


#2

Amy, I am a beginning "whatever"can’t dare to call myself a
jeweler…but I just set up to produce one of the bracelets you have
described…I saw one in a mag, had done some woven bracelets switch
back and forth between bead work and silversmithing and thought
here’s a chance to put it together…I was wondering if the bead part
could somehow be detachable so that the silver could be cleaned? as
in the end of the weaving attaches and detaches from the silver???
Lisa…


#3

Dear Amy: I have been using one of the members of this list for my
casting - Daniel Grandi at Racecar Jewelry. Daniel is honest and
wonderful about explaining things. He truly seems to understand what
makes pitting, etc. - all those problems which result in poor castings

  • and how to avoid them. I am very pleased with his work.
    Additionally, he is a perfectionist and I can’t imagine him letting
    things out of his shop which aren’t first quality. I urge you to
    contact him at jagman425@aol.com No, I am no relation to him, just a
    very happy customer.

Shael
dakotahdog@msn.com


#4
    Orchidians, what did I do wrong? Is my design intrinsically
un-castable? 

Amy-R I do think you figured out what went wrong by yourself. Casting
anything large (or indeed) anything in fine silver is extremely
difficult. You see alloys have a melting range when going from a
solid stage to a liquid stage, but pure metals do not. So trying to
cast a large piece in a pure metal is a problem since when the heat
supply is removed the metal begins to solidify before it completely
fills the mold. There should not be any problem casting the bracelet
in sterling and this would hold it’s shape better than the fine
silver. FWIW JZD


#5

Doug Zaruba,

is this item you need cast something that can be cast in parts and
then soldered together. I my self am a smith with casting equipment
on premises, and may be able to do what it is you require, but I would
need to know more and see specs before I could say any more. The
reason I ask about being cast in sections is that it may actually be a
simpler process, yet yield the same results that way.

I have done work with canes, both doing inlay as well as handles, and
would love to know more about your project. If I can’t help you, I
may know of a person who can.

Alex Austin
Austin Creations
PO Box 1109
Rimrock Az, 86335

(520) 567-3044
fax (520) 567-3345
www.austincreations.org


#6

Hello Amy, Casting a bracelet isn’t heavy or difficult depending on
the thicknes of the material.here is some about the
casting procedure in order to help you understand the problem of the
caster. 1.If you setup a piece which need to be cast and specialy with
bigger pieces,you need several spreu’s starting from the button (is
where the melted metal will be poored into) going to your
bracelet.Those sprue’s need to be large enough to keep the metal long
enough in a liquid status.The reason for this is next.As the metal
starts to cool down after its been cast,it tends to shrink.During the
shrinking proces it will withdraw metal from those sprue’s.As you
know small pieces shrink much faster then larger and bigger
pieces,that means,if you not have enough sprues to feed your
bracelet, you’ll never have one solid piece because a shortness of
metal feeding your object. 2.When the piece is cast and depending on
the thickness of your bracelet,it needs a certain time to cool down
without quenching.If you quench it to fast … it will break due to
the temperature shock. 3.Making a wax out of this bracelet isn’t that
easy.The wax need to be injected and again is a subject to shrinkage
having the same problem as the casting proces.

I have to admit,I’ve never casted an object like this and I do not
know everything about it since I’m more into smaller designs. Why
don’t you start by making the bracelet out of wax? It’s easy to
handel and you don’t need to make a mold.Sheet wax isn’t that
expensive and you skip the moldmaking procedure.You could make a
number of bracelets in one hour!

I’m not in the position of critisizing this caster since I don’t know
exactly what happend and I don’t know if I could do better then he
did,but maybe you want to check another manufacturer with all respect
to this caster.

I hope that you understand a little bit more about this casting
procedure and hope that an other fellow orchid member jumps on this
problem to give you an even better picture of what is going on. I’m
sorry if you didn’t get the whole picture due to a lack of my english
translation. Wish you good luck and hang in there, Pedro
Palonso@t-online.de


#7

Hello Amy, If the jeweler produced a mold for you, it should now be
in your possession, assuming that you paid for it. If the company
produced 2 castings, the mold must work. Silicone rubber is a good
material, although not without its own problems. I’ve been using
Castoldo’s no- shrink pink for some time and find it terrific. Have
you looked in the catalogs of some of the larger casting houses to
find if your bracelet or something very similar is available?If not,
send your model out to another caster. Good luck. Tom Arnold


#8

Hi all, I can’t resist jumping in here. It’s been a long time since I
commented on something. Because I have been casting for jewelry
artists for 25 years I might be able to add a few insights. Casting
fine silver is indeed more difficult than sterling but by no means
impossible. Nothing is impossible…just more expensive. Working with
fine metals and alloyed metals for hundreds of artists has given me
lots of experience with the possible results. The real chalenge is
getting consistant and reliable wax injections. This alone can drive
up the casting cost. Also consider that even a perfect casting has a
large crystal structure in it that will greatly reduce it’s tensile
strength. Imagine your cuff bracelet being squeezed a dozen times by
your customer and then returned when it breaks! And it will break! A
fabricated bracelet made from sheet stock will last much longer
because all those large crystals have been rolled out to make a long
and strong grain. Bangles or a heavy cuff would be a better candidate
for casting. I hope this sheds some light on your dilema. John,
J.A.Henkel Co.Inc. Moldmaking, Casting & Finishing


#9

John: I would like to know more about your casting service as we are
not casting platinum in house yet. We are thinking of getting the
equipment for casting platinum and any insight from you would be of
great help. I know we need a vertical caster and I know we need a
heavy duty investment mixer and some flask liners and some nasty acids
and special investment. Is there any books that you would suggest?

Michael R . Mathews Sr.


#10

Dear Michael,

If you’re planning to cast only small amounts of platinum, you might
want to give Jurgen Maerz a call at Platinum Guild and ask him about
the work he’s been doing with Marc Robinson of PM West on fast-setting
investments. From what Marc tells me, for small volume castings, there
are some pretty fascinating developments out there that may reduce
your need for equipment. (The new investment, for example, doesn’t
require the type of heavy duty mixers other platinum investments do.)
The new approach even allowed Jurgen and Marc to successfully cast
diamonds in place, if you can believe that, and Marc says the quality
of the castings is amazingly better than other methods he’s tried.

Anyway, Marc is really excited about these developments. I’m not a
caster, so I can’t say for certain how revolutionary it will prove to
be, but it could be worth checking it out further before you make the
equipment investment. Marc’s written an article that will appear in
AJM sometime in the coming months, and Jurgen can probably give you
some guidance, as well. (PGI’s number is 979-760-8279, or e-mail him
at jurgen@pgiusa.com)

Hope that helps.
Suzanne

Suzanne Wade
writer/editor
SuWade@ici.net
Phone: (508) 339-7366
Fax: (520) 563-8255


#11

Hi Folks,

I’m thinking through the process for making a gemstone inlaid cast
bracelet, but have one question. Should I carve it and cast it flat,
then form it to a cuff shape, or should I carve it and cast it
already “round?” It would be easier to do it flat, since the
symmetry will be easier to see, and depth easier to manage. My
concern is that, due to the relative brittleness of a casting, it
will crack during forming. However, I do not have a chunk of wax
massive enough to carve the model “in the round.”

Thoughts?

Dave


#12

There’s an additional problem in casting flat and then forming.
Bezels will no longer fit the stones you carved them for! The bases
of the settings will curve and you’ll have to re-cut them, the sides
will no longer be level, you’ll have to model them taller than you
need and then file them down. The shape will elongate in the
direction of the curve,

Melt your wax onto the bracelet mandrel - wrap it first with
aluminum foil so that it comes off easily - THEN carve it.

Tony Konrath Gold and Stone http://www.goldandstone.com


#13

Dave,

I would definitely suggest casting the bracelet in the round.
Stuller has swhat they call “Oval Bracelet Bar” in two sizes, 3 1/8"
x 2 5/8" x 4 5/8" and 3 5/8" x 2 3/4" x 3 5/8". Both sizes are
available in Blue & Green @ $12 each. I just completed a large
bracelet using this wax. It made it much easier. Joel

Joel Schwalb
@Joel_Schwalb
www.schwalbstudio.com


#14

Hi Dave,

I vote for casting it in the cuff shape and avoiding any trouble you
would run into trying to form a casting. Matt sells a carving wax
bracelet block, much like a ring tube, and I have used this
successfully on several occassions to make very detailed cast
bracelets. I think with careful measuring and carving you can
acheive the same precision with the cuff shape as you could with a
flat shape. Good luck!

Best regards,
John


#15

Dave, I’ve cast a heavy cuff bracelet already round. I sprued it
with multiple sprus on the inside. I used Aluwax dental impression
wax. It comes in sheet form and is somewhat brittle when cool. It
can be carefully carved, added to if you like,and then warmed and
formed round. I carved panels of designs and put them together on a
bracelet mandrel and then drizzled a layer of inlay wax on the
inside and smoothed it for a layer of added strength. You could form
bezels for the stones out of wax after it was round with no
problems. Have you used soft waxes and build up before or only
carved hard wax? Annette


#16

Hi Dave and all, Your instinct about bending the bracelet after it is
cast is correct. Not only can the casting stress by bending it after
it is cast, it will also stretch and change your inlay pattern.
Carving wax can be purchased in big blocks from most of the tool
suppliers. There has been much discussion about this and you can find
it in the archives. I suggest that you address your symmetry concerns
with a good pair of dividers and lots of planning. One problem I have
found with a cast cuff style bracelet (as opposed to a bangle) is
that folks will tend to squeeze to adjust it. This, over a shorter
period of repetitions than a forged cuff, can produce cracking. The
most successful cast cuffs I’ve seen tend to be on the heavy side.
You will have your best results casting the bracelet horizontally
with several sprues with the addition of reservoir sprues close by
the piece. don’t skimp on the button. Good casting to you. John,
J.A.Henkel Co.,Inc.Moldmaking Casting Finishing, Producing Solutions
for Jewelry Artists


#17

Bending the casting could lead to distortion of the inlay holes and
cracking of the casting, so shape it the way you want it and make the
mold on the final shaped model. Most carving wax is available in
large blocks and sheets- Matt Wax has a new 3x6 inch assortment with
finished surfaces, very nice for layout.

Rick Hamilton


#18

Dave, Some thoughts on casting a bracelet.

  1. Casting a flat bracelet would require a flask taller that 6".
    It might be easier to carve but would be more of a problem in
    casting. I would recommend attaching sprues to one end and at least
    the middle of the flat bracelet.

  2. Forming a flat cast bracelet could cause tears or cracks.
    Hammering the flat bracelet to form it could flatten any raised
    portions.

  3. The design can be worked out on paper and transferred to the
    round piece of wax. Rubber cement will hold the design to the wax
    long enough to transfer the pattern.

I turn wax on my foredom when I make a carved bracelet. Ferris wax
can be purchased in a one pound block that is 3.5" x 1.5" x 6".
There are manufacturers that produce larger waxes. I cut a section
from the turned wax and sprue it on the ends and also run sprues
down to the section of the wax opposite the cut out section. Once
the bracelet is cast I do the final forming on a baseball bat. Build
up wax bracelet can be formed and worked on a baseball bat or if
available on a bracelet mandrel.

I have a paper that I prepared on turning wax on a foredom. Its a
very simple process. Would be glad to sent you a copy if you are
interested. No cost. I just need your snail mail address.

Lee


#19

Dave, I had similar problems trying to deal with a bracelot design.
What I eventually did was carve half of the bracelot out of wax.
curved it under hot water, cast it, made a mold of that half and then
put two pieces together to make a completed bracelot in wax. There
is probably an easier way, but I could’nt come up with any other
solution. Good Luck, Michael


#20

Dave What about carving it flat then froming it in the wax prior to
casting, you could then easily fix any distotion that could occur in
the forming stage. I would not recomend that you cast it flat then
form the shape it will most probably crack due to the brittleness of
the cast metal. Regards John in oz