Casting 24k gold

Jewelry Discussion
1

My brother wants me to make him 24k gold wedding bands. I have never
cast 24k and I am sure there are differences I need to know. If
anyone could offer advice I would surely appreciate it. If I decide
to fabricate instead, How do I solder the seam?

Thanks
LaVerne

2

Hi there

I would strongly advise fabricating them (it is stronger, they will
have a better crystal structure and it is less expensive if you are
only doing two). Start with wire of the appropriate cross section for
the ring, wrap it around a mandrel (or bend it with pliers) into the
appropriate circular shape with a little bit of overlap. Cut through
the overlapping join with your saw and tap the ring up so that the
join meets as well as it can. Then saw through the join again to get
them parallel. You might need to do this a few times. When you have a
perfect join which is completely flush, gently open the ring out
(less than 1mm, you don’t want to unspring it), flux the inside of
the join and slot in a very thin pallion of solder. The solder should
now be trapped in the join. Heat the ring up, when it gets to
temperature the solder will flow and fill the gap. If you have
tweezers lightly compressing the ring while you heat, you will get a
very good join.

You will need a ring anvil to make the whole thing round again once
you have finished. Make it a size or two too small and tap it to fit,
otherwise you will need to go through this process again to remove
segments.

Chris Penner

3

LaVerne

I hope your brother and sister-in-law aren’t planning on wearing the
24k bands very much. Maybe the ceremony and then putting them away
for anniversary wear. 24k is way too soft too see much usage hence
alloying the gold to make 18k or 14k…wears much better.

Frank

4

It happens I just cast an 24K ring this morning. It casts OK. but it
is TOO SOFT!!! It looks really nice but even a fairly heavy casting
I can squeeze it out of round with my fingers. I tried to talk my
customer into 22K, but for some reason 24K is what they insisted on.

Stephen Walker

5 
My brother wants me to make him 24k gold wedding bands. I have
never cast 24k and I am sure there are differences I need to know.
If anyone could offer advice I would surely appreciate it. If I
decide to fabricate instead, How do I solder the seam?

No advice for you, but for your brother. I’m sure he already knows
it, but 24k is going to be soft and he’ll want to reshape the rings
every year or so, or whenever they distort enough to be difficult to
take off.

I’ve been wearing a 24k wedding band for 44 years now. I watched it
being made in a one-room house in Korea. The goldsmith actually cast
a bar in an open mold, then fabricated the ring. I believe he
actually fused the seam, but it’s been a long time.

Al Balmer
Sun City, AZ

6 
My brother wants me to make him 24k gold wedding bands. I have
never cast 24k and I am sure there are differences I need to

First, I would strongly - very strongly - recommend that you use 22k
instead. 24kt will be like a band of butter around his finger, where
22k will have just that little bit of hardness and still look like
“real gold”. In either case, they will cast perfectly with usual
care - it’s the alloys that get you. If you do solder, use 18kt.
solder for 22k, and make up a bit of 22k solder for 24k. (22k =.916,
multiply gold weight by.091 to get the alloy to add to the gold,
then use 50/50 copper silver for alloy). Or just weld it. It’s easy,
it’s the softness that is the trouble, if anything.

7

convince him/them that 24 is too soft to wear well.and 22 kt looks
almost as rich…18kt royal yellow is strong and looks very rich…but
if he is set on 24kt, then cast away, and you can simply fuse the
seams by using filings mixed with a bit of paste type flux, or if
you have a laser welder it will do the trick. I had a person that
also wanted 24 kt bands, my solution was to make an 18 kt. blank with
a channel that i then filled witha rectangular wire of 24kt. after 20
years it shows very little wear on his band, but her band is
thinning just slightly probably due to her being a potter and dealing
with gritty stuff on a regular basis… One jeweler i know used 24kt.
PMC and got great results after kiln firing it and backing it ( the
part that goes against the finger) with a 14 kt bearing/collar.
however it has been dented, scratches easily and all the other things
that can happen when using 24karat, and that was in about 1997- i
don’t think mitsubishi makes pmc in 24 kt anymore…

8

LaVerne,

This may be an ideal case of “customer education.” Ask your brother
why he wants the rings to be 24K and explain the down-side of that
choice (they will be soft and “mush” out of shape very easily, and
not handle “normal wear-and-tear” easily at all). Offer some
suggestions for alternatives that will help him meet his goals.

If he really likes the rich, dark look of gold, make the ring from
18K and depletion gild it or apply 24K keum boo on the surface… or
use a 24K bimetal. On the other hand, if it’s the purity of the metal
that he likes, ask whether a different, more durable pure metal might
work for him. If he’s insistent that 24K gold is what he wants, ask
him about whether you can do an inlay of it into steel or platinum or
some other contrasting metal… or even a different color of gold.

If you do end up making a 24K ring, I would recommend either fusing
it (not soldering it) or casting it. That will avoid the color
difference, melting point issues, and other possible problems of a
solder seam.

Hope this helps!

Karen Goeller
No Limitations Designs
www.nolimitations.com

9

24K is pretty interesting stuff. 24K melts at a high temp [around
2000 F] and cools fast. It’s liquidious state is very brief. You
need to cast this stuff fast. It will cool before it gets in the
flask if you aren’t careful. What you can do is use a hot flask, and
over heat your metal by several seconds. This way you are building up
reseve heat in the metal giving you a little time to get it in the
flask but you have only a heart beat to get it poured. Since you have
no alloy to burn up you aren’t hurting the metal. If you need to
fabricate you can try and fuse the seam but 24K will go from solid to
liquid in a hearbeat and then cool solid just as fast. If you try and
fuse or solder whatever hardness you have worked into the gold will
most likely disappear. You can use 22K solder but you will have a
seam that will show.

Good luck, Dennis

10

Ri

If I decide to fabricate instead, How do I solder the seam?

I would weld it. The seam can be beaten to shape. If you have a ring
stretcher, the band can be beaten.compressed and beaten more to get
the shape that you want with minimum stock removal and a seamless
product as an end result. Have fun!

Bruce D. Holmgrain
JA Certified Master Benchjeweler

11

if it was me i would cast them in the centrifuge, if you fabricate
you can fuse the seam without solder i saw some good advise on
another post about making them a size smaller and forging them up -
goo

12

An inner band of some lower K might make the bands more wearable?

KPK

13

Hi Richard,

One potential solution is using a 24k gold micro-alloy. Puregold has
been making micro alloys for a little while now - and per their
website - their 24k gold can be hardened to approx 180 vickers

I am not a hallmarking expert - but again per their website, for
gold to be hallmarked as 24k - it only needs to be 99.7% gold by
weight. Their alloy is 99.85% gold by weight so it would meet the
hallmarking requirements (at least I assume in the USA).

http://www.allpuregold.com

As a usual disclaimer - I have not done any business with Puregold
and I am not affiliated with them - just presenting a possible
solution to your brother’s request that circumvents some of the
problems the other Orchid members have correctly brought up.

Does anyone have any experience working with micro-alloys like the
one on puregold’s website?

-Bradley Zastrow

14

Hi.

If I decide to fabricate instead, How do I solder the seam?

I am saying this entirely from memory (not absolutely reliable) but
I think Steve Binnion has a tutorial somewhere on making a seamless
ring from a bar of mokume. The idea is to split the metal and
gradualy open it out to a rough circle then forge it round. This
might work for you if you use 24ct. I have wanted to try this method
but have not got round to it. the usual story, not enough time.

Perhaps someone else can supply the links if you want to look at the
tutorial.

Cheers from Ruth

15 
I would weld it. The seam can be beaten to shape. If you have a
ring stretcher, the band can be beaten.compressed and beaten more
to get the shape that you want with minimum stock removal and a
seamless product as an end result. Have fun!

Bruce is has got it right, and by welding and forging the ring will
get harder and be more durable than when cast which is a real
benefit with 24K

Jim

James Binnion
@James_Binnion
James Binnion Metal Arts

360-756-6550

16

Another way you could go is to cast the rings in simple molds. No
joining and, with careful measuring, no waste.

  1. Make a wax master for each ring, keeping the design simple and
    chunky as befitting a 24k ring. Cast it in Delft sand or similar,
    with a short feeder sprue and a very small vent opposite. With luck
    the ammount you pour will be just enough to fill the ring cavity and
    you’ll have no sprue to cut off.

  2. I call this method the ‘Tree Trunk Ring’ method. Drill a wide
    hole into wood, and a smaller hole inside it. Put a wooden dowel into
    the slammer hole. This leaves a ring-shaped cavity. Pour the gold
    into this.

In both cases you will have very little post-casting work to do, to
polish it would be pure folly.

Brian

B r i a n A d a m
e y e g l a s s e s j e w e l l e r y
B u s h J e w e l l e r y W o r k s h o p s
Auckland NEW ZEALAND
www.adam.co.nz

17

You could make the outsde in 24K–welded and fabricated, cast,
whatever-- end then line it with a thick liner-- 18ga of 18k or even
a contrasting gold alloy. He might see something from the side, but
the look will be there. Of course, this doesn’t stop the outside
(24k) from wearing. It all depeneds on the detail.

Andy

18

Here’s a novel solution to your query. Use a disk of pure gold
instead of a silver coin.

How to make a coin ring
http://tinyurl.com/e7u8x

Regards, Gary Wooding

19

From allpuregold.com:

24 karat gold has been considered too soft to manufacture jewelry
that will withstand everyday wear.

The Thai’s and the Chinese (among others) will be very unhappy to
hear this since they’ve been making and wearing.9999 gold for
centuries!

However, PureGold's microalloyed 24K gold has greatly improved
hardness and strength when properly carried through the
manufacturing process. This enables the production of jewelry that
can carry a 24K hallmark in almost all countries of the world and
yet retains its finish and structure in everyday wear."

I create 24k gold jewelry and wear it every day (as well as.9999
silver jewelry). This company’s practice of calling unpure gold 24k
means that I need to have a.9999 stamp made since my 24k stamp is now
polluted.

Thanks a lot allpuregold.

Doc

20 
Perhaps someone else can supply the links if you want to look at
the tutorial.

I don’t know about any tutorial. I just run some 24k gold thru my
mill to thin it out, cut off snippets, and pretend they are solder.