Re: [CAD_CAM_EDM_DRO] Make or repair jewelry ?

turbulatordude wrote:

>Hi,
>
>Does anyone make or repair jewlery ? specifically gold ?
>
>I am thinking about what it will take to make my wife a ring for our
>aniversary. or possibly modify one she already has.
>
>Dave
>
>
>

Hi Dave:
If you are a machinist, which I assume you are, you need to get used
to the idea that the material you're going to use is VERY expensive, so
you don't want to go hogging out your job from a chunk of barstock.
Every chip you remove is worth enough to make it worth saving...even the
filings.
In recognition of this fact, the jewellers art is a bit different from
the machinists art, but you can take good advantage of the skills you
possess as a machinist nonetheless.
Jewellers are either fabricators or casters for the most part on any
given project...sometimes both combined.
The nature of the design dictates the method of construction.
So, if your design is a fairly compact one without lots of skinny
wire-like details or thin sheets, a casting is the usual choice, and I
suspect this is the route you'll probably go.
So your machining skills can come into play designing and making the
pattern for the casting.
Overwhelmingly commonly, jewellery is cast using a process called "lost
wax", which, in simplest form, consists of carving the pattern in wax,
investing it in a plaster-like material, melting out the wax, and
pouring in the gold.
Be aware that the devil is in the details for this process, just as it
is in anything you wish to do well, so there's a LOT more involved than
what I just described.
For this reason, I recommend that you have the actual casting done by a
jewlery caster or a dental laboratory...they will have the equipment and
the expertise to give you a good quality casting, and free you to
concentrate on making a nice design and doing the wax carving.
Depending on your design, it can be milled with CNC or carved by hand,
or any combination thereof.
It can be added to by building up wax in areas that are more convenient
to do this way , and it can be made of many other materials than just wax.
A common choice is a carveable wax...the brand I used to use is "Ferris
File-a-Wax".
I also really like a dental acrylic called "Relate" which is very strong
and can be handled far more aggressively than a wax pattern, even in
very thin sections.
Once you are satisfied with the pattern, take the time to polish the wax
really well...the better the pattern, the less gold is lost in
finishing, and the less labour is spent too.
The fidelity of detail and the accuracy of form that can be achieved
with lost wax casting has to be seen to be believed, so invest lots of
time making the pattern as near to perfect as you can get it.
Plan places where you can accept a sprue...this is the point at which
the gold will be introduced into the mold cavity, and a stub will
appear on the raw casting that will need to be filed and polished away.
The rule-of-thumb, is to place the sprue in the heaviest section of the
casting, and to place it on a convex or flat contour if at all possible.
You want the metal next to the sprue to freeze last as it cools, and you
want the stub to be easy to trim and blend into the surrounding surface.
Putting the sprue into the bottom of a concave depression makes this
task needlessly difficult.
Once you get the casting back, it's a matter of finishing it...basic
sanding and polishing here.
Then you need to set any stones you may wish to incorporate into your
design...that's a whole 'nother art.
Have fun with it Dave...it's a marvellously rewarding challenge to do,
and not difficult at all to do really well, provided you're willing to
take your time.
Besides, you'll make your lady VERY happy...and that's a satisfaction
worth every bit of the effort!!!
Cheers

Marcus