Back to Ganoksin | FAQ | Contact

Retouch / Filing gold castings


#1

Dear Khun Sunil!

Welcome to Orchid and Sawadee Krap-pom!

I am also running a manufacturing operation in Thailand and will
be happy to discuss region_specific manufacturing issues. Feel
free to call me at 422 1254 .

BTW, I’m located in Mooban Panuragsee, Bangkruei and you?

Chok Dee

Hanuman


#2

Hello all list members,

I am new to jewelry line and have recently set up a factory in
Thailand for manufacturing Gold & Silver Jewelry. After casting
the usual practice is to file and retouch each and every piece
and I observe this process is most expensive in terms of time
and metal loss. I am looking for some solution which could avoid
this step; I mean is there any way that the casted metal is
received in such fine condition that it would not require any
filing / retouching. I appreciate advise from experienced
members. Regards

SUNIL KHINVASARA
BANGKOK
TEL 66 2 6788334 / FAX 662 2863650
Email: sunilk@ksc15.th.com


#3

Sunil:

I work with casters who cast for me, but from what they tell me
and what I have read, you need to get the best rubber mold you
can ( which means really polishing up the master model before
making the mold). Then the wax should look very smooth, without
defects. You can fix (polish, etc.) the wax, but it is more
efficient to have the best mold you can get, then every wax will
be about perfect. Sprues do have to be cut off castings and the
"button" which is left ground off with a fine grinding wheel
(faster than filing), but a really good mold will not need other
prep before being vibro finished in the tumbler. There has been
a good bit of discussion of this method lately, including a
fairly detailed post on 12/2 by me about a particular vibro
system a friend of mine uses. Experience with such a system
will show you how fine the finish on your casting needs to be
before you put it in the tumbler for the “first cut” (240 grit
pyramids or cones). As far as I know the tumbling process will
take out the scratches of the fine grinding wheel used to remove
the sprue button or scratches from a mizzy wheel used on parting
lines, etc.

If you think about it, in the manufacturing business, making
100’s of pieces off one mold, it will pay x100 in time if you get
the mold right the first time. Poor mold gives a casting which
has to be worked on by hand 10 minutes each casting before being
thrown in the tumbler. Can easily tumble finish 200 rings in a 3
gallon tumbler in about 18 hours total. There are magnetic and
centrifugal systems which are faster, but much more expensive
— look in Rio catalog for details on all these, but don’t
necessarily buy from them. HTH. E-mail me here on list or at
@Jess4203 for any questions. Others on the list have hands
on experience with tumbling.


#4

Jess:

I work with casters who cast for me, but from what they tell me
and what I have read, you need to get the best rubber mold you
can ( which means really polishing up the master model before
making the mold). Then the wax should look very smooth, without
defects. You can fix (polish, etc.) the wax, but it is more
efficient to have the best mold you can get, then every wax will
be about perfect.

Is there any specific suggestion on the quality rubber mold. We
have 2 options; first is the usual rubber and second is silicon.
Silicon is expensive but if it reduces filing work, then it may
prove cheaper.

 Sprues do have to be cut off castings and the "button" which
is left ground off with a fine grinding wheel (faster than
filing), but a really good mold will not need other prep before
being vibro finished in the tumbler.

For cutting off castings, we normally use normal cutting pliers.
Is is possible to find cutting pliers with circular blade so
that the castings may be taken off smoothly and closely with the
shank? Do you any recommendation for any other specific tool. The
objective is to minimize time in grinding sprue button and to
minimize gold loss also.

SUNIL KHINVASARA
BANGKOK
TEL 66 2 6788334 / FAX 662 2863650
Email: sunilk@ksc15.th.com