Sandcast and tufa cast bracelets have been cast in the flat for
centuries, using only gravity flow (vs. centrifugal force or vacuum)
then formed. These tend to be somewhat substantial in mass, so I
don’t know if it will work for a delicate design.
traditional american indian indian jewelery is cast flat and then
pounded around a mandrel to shape. on a limited basis i’ve done the
same and had very good success . ocassionally you will crack from
porosity but the crack can usually be soldered anyway. i suppose if
you make a really complex wax you might want to cover all your bases
by making a rubber mold before you bend the piece. do remember that
the molded wax casting will have some shrinkage issues you may not
like . as a second choice you could bend the finished wax to shape
but that would require intense spruing to get the castng to flow
properly anyway. hope it helps
Dave Otto
Dave, I don’t know if this would work since I’m sort of new to this,
but wouldn’t letting the casting cool slowly in the flask (maybe
inside a closed kiln for slower cooling?) anneal it and make it
flexible enough to bend/work into the bracelet shape? Granted, it’s
harder to get the piece out of the investment if you don’t quench it
and let the investment explode out, but that might work better as
long as the design allows you to shape the bracelet into a curve from
a flat shape without distorting it too much.
–Marcy Osedo
Hi Dave, A couple Ideas on making a model/ casting a cuff
bracelet… We do a fair amount of model making and casting of
bracelets with excellent results…
Sometimes, I will make a cuff bracelet with no design on it… thick
enough so I can put the design on later… Make a mold of the cuff ,
then put the design I want into the Injected wax… Many interesting
ways to do this… SometimesI will make the model flat, with a cut
away area that i will put the design into later… Mold it, shoot a
wax… Then, very slowly after having formed the Injection wax into
the shape I want, I will slowly add purple or blue carving wax to
the areas I want to carve… This takes a bit of time as You have to
be careful to not melt the injection wax… I drop the melted carving
wax(using a wax tree ing iron in various areas until the area is
covered in carving wax… then I carve the detail in. You can also cut
sections of carving wax and weld it into the injection wax…
sometimes we just make the model flat, in wax or sterling… then we
shape the sterling flat casting or the flat metal model , If there
are stress marks in it, they can be filled or burned out of the
rubber mold… You can use epoxy to fill the model stress marks if
neccessary… or a 96% tin/ 4% silver plumbers solder which will
fill nicely and clean up perfect…
However, the absolute easiest and best way is to buy sheet Pewter (
very inexpensive and a large selection) from Contenti Supply
(800-343-3364) and simply carve the model out of pewter… the pewter
is easily bent without getting stress marks and is as easy to carve
as carving wax… It can also be finished /polished so it looks
perfect before molding. The best person to talk to at the contenti
company about the pewter sheet and solder is Steve as he is a model
maker/salesman and can give you exactly what you need to do it.
As far as casting goes, we cast cuffs with a single large sprue
attached in the correct location so that the metal flows into the
cavity correctly… There is no need for multi sprues, reservoirs
…etc…casting flask temp around 800 oF Metal temp around 1850 oF for
deox metal
Casting cuff bracelets is expensive as you can’t get many in a large
flask unless they are not very wide… We cast some that are 1/2
wide… 1" wide and 2 " wide… Hope this helps.
Daniel Grandi We do casting,finishing and a whole lot more for
individuals,designers, stores and catalogs. Please contact:
sales@racecarjewelry.com
Thanks, everyone, for the great feedback. Over the recent Orchid
hiatus, I think I have decided how to approach this problem. A little
more background, first. The bracelet is going to be inlaid,
southwestern style, so I won’t cut the stones until after all the
metal work is done. Distortion in the bending wouldn’t be an issue
for the inlay. It is a client designed one-off piece, so rubber
molding isn’t in the plans. Just cast and go.
I’m planning to create a form of the proper oval for the client’s
wrist, and build up carving wax to the size I need for the model,
then carve the bracelet from that. Due to the deep (thick) design of
the bracelet, I’m afraid that bending, either in wax or silver, will
have a detrimental effect on the piece.
I’ll be using one of our master casters on Orchid to do the casting
job when the time comes.
Thanks again,
Dave
Dave Sebaste
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)
dave@sebaste.com
http://www.CarolinaArtisans.com <
Dave, I don't know if this would work since I'm sort of new to this, but wouldn't letting the casting cool slowly in the flask (maybe inside a closed kiln for slower cooling?) anneal it and make it flexible enough to bend/work into the bracelet shape?
silver is softest when quenched, not slowly cooled. Slow cooling of
most jewelery metals can result in what’s called age hardening, or
more properly, precipitation hardening. Slow cooling is generally
needed only when a quench causes too much stress, causing cracking.
This occurs mostly in metals that are “hot short”, meaning they have
little strength when hot. Many white golds are this way. Rose
gold, too. but both of these are still softer when quenched, and
rose golds in particular can get VERY hard and brittle if slow
cooled. A traditional means of dealing with this is to quench in
alcohol after annealing, which is a gentler quench than water, yet
still fast enough to prevent age hardening. this of course is
useless info for a casting. but generally the idea is to let the
casting cool enough so it’s no longer too hot to quench without
cracking. If you then need the casting fully annealed for working,
it’s best to do that annealing as a seperate operation after you’ve
taken it out of the investment… And another problem with slow
cooling that’s applicable here is that slow cooling will give you a
larger grain structure in the metal, which is more likely to distort
or break when bent. castings in general already have a very coarse
grain structure, as compared to fabricated metal, and are more prone
to problems when being bent. But the real problem isn’t
flexibility. The casting, normally quenched and removed, will be
quite soft enough to bend. the problem is that doing this will cause
a LOT of distortion in the design portion, since the inner, solid
layer of the bracelet will tend to retain it’s length dimension,
while the weaker design area, bending to a larger circumfrence, will
have to stretch considerably to fit around the inside layer.
Peter