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Making my own 18k alloy


#1

hi! so now i’ve decided to use gold in my work, and i’ve also
decided to make my own alloy, as i hear it is cheaper to do this. i
also have more time than money, so why not? i know the percentages
for how much gold vs. how much alloy. what i don’t know is…exactly
how much fine silver and exactly how much copper do i put in?
although i like a very orange color, i want to keep the color as
close as i can to hoover and strong’s “royal yellow”. i am not
worried how to do the process, i am just asking about the
percentages of each metal, preferably in terms of percentages, not
pennyweights or grams. anyone have any ideas?

thanks!
joanna gollberg


#2

I posted this before, but it doesn’t hurt to put it up again. I did
work for a store, and they wanted everything the same alloy, so the
told me the mix. It has just enough copper to take the green off -
it’s about as yellow as 18kt can be, and everybody loves it. Plus it
works like butter. As with any alloy, I’d suggest you try a small
amount and see if you like it. Also, most important: I make mine 2
ounces at a time, so I melt the alloy together first, then pickle it,
then re-melt it and pour it into a pitcher of water to make shot.
Whether you make shot or not, it’s important to melt the alloy first,
and then add that to you gold. Don’t just put 3 metals in a crucible.
The alloy is 80% fine silver, and 20% copper - I use electrical wire,
which is 99.9. That works out to 40 dwt. silver, 10 dwt. copper, by
the way.


#3

Hi Joanna;

so now i've decided to use gold in my work, and i've also decided
to make my own alloy

If I were you, I wouldn’t try to make my own alloy to add to the
gold. The savings is insignificant and melting the copper is a pain.
A lot of companies, Stuller among them, sell alloys, in a wide range
of colors, to add to your 24 karat gold. They even have different
alloys designed for casting or rolling into sheet and wire. Even
then, it’s not so easy to get the alloy and the gold to melt and mix
well. Find the melting temperatures of the gold and the alloy and
melt the higher temperature one first, adding the second metal a
little at a time. When you get them melted and mixed, pour into a
deep (at least a foot) container of cold water to disperse the metal
into shot. Pour from a foot or so above the water and pour slowly.
Then you can melt that to cast ingots or cast into molds.

David L. Huffman


#4

Joanna,

I think what you mean is that you want to “alloy” your own 18K gold.
Easy enough to do. Now, using a metal chart, like the one at the
back of Tim McCreight’s book, “The Complete Metalsmith”, you can find
all the “ingredients” to make your own alloys to mix with pure gold
or pure silver.

Another way I would highly recommend is to buy a ready-mixed alloy
from one of the big metal suppliers, like Hoover and Strong, David
Fell, United Metals, or others, and just add it to the pure gold or
silver. By mixing your own alloy (which is cheap to buy) with pure
gold or silver, you can get the color and workability you desire,
with minimum cost. I make my own no fire-scale sterling with United
Metals S88 alloy and pure silver, and mix deep yellow 14K and 18K
with David Fell’s alloys. All I need to do is buy pure silver or pure
gold from my neighborhood coin dealer, and use my stash of alloys to
create whatever I want in any amount.

Happy alloying!
Jay Whaley


#5

The World Gold Council have some handy tables on their website.

Dale Porter


#6

Handy and Harman’s composition

Yellow - 14K - Gold 58.33 %, Silver 5.0 %, Copper 30 %, Zinc 6.67 %.
Yellow - 18K - Gold 75.00 %, Silver 15 %, Copper 10 %,

Bright yellow Gold 18K -Silver and Copper 12.5% each.
Reddish yellow Gold 18K - Silver 8.3%, Copper 16.7%
Orange Gold 18K - Copper 25%

WGC data sheet

14K
Au, Ag, Cu, Zn
58.5%, 9%, 32.5 %. -Red(rose)
58.5%, 20.5%, 21.00%. -Yellow

18K
Au, Ag, Cu,
75.00%, 9.00 %, 16.00% pink.
75.00%, 4.5 %, 20.5% rose

Hope this helps

May God bless us all with total health Physical,. Mental, Spiritual,
Social.

Let us Strive to be Happy in all circumstances.

Umesh


#7

Joanna,

Stuller’s royal yellow casting grain formula as listed in their
catalog is 6.8% copper, 16.5% silver and 1.5% zinc. That leaves.2%
unaccounted for. They’re probably formulating it to provide a
slightly higher karat gold at .752. My bet is it’s pretty close to
the Hoover formula.

Larry


#8
Pour from a foot or so above the water and pour slowly. Then you
can melt that to cast ingots or cast into molds. 

Why do you need to make shot first? Why not just pour an ingot?

Noel


#9

Hi

Remember to get every ingredient as pure as the gold, to avoid all
kinds of problems. Example-Some have used copper wire that had solder
or was very oxidized to their regret.

Commercial alloys are very inexpensive, most of the suppliers will
sell you very good copper or silver when you need it. Making your own
alloy is far more valuable from a learning or control standpoint than
saving any money.

Daniel Ballard
PMWest


#10

Hi Noel;

Why do you need to make shot first? Why not just pour an ingot? 

Actually, you don’t, but if you haven’t done a lot of this sort of
thing, you’re likely not to know how to tell when you’ve got all the
gold and the alloys mixed in the melt. And if you don’t get them
mixed, you will find the bits of unmixed metal, either gold or alloy,
showing up during the final polishing, and there’s not a lot you can
do about it then. If you stir it with a carbon rod while it’s
melting, you can actually feel the bits that are unmelted, but a
beginner probably won’t catch it. So, melting and pouring into shot
gives you much better odds that the second melt will integrate the
metals thoroughly. The shot is very much like random corn-flake like
petals, very open, Mixed or not, it all melts pretty much
simultaneously, so it’s not likely that solid, larger lumps of alloy
or 24K gold will happen.

David L. Huffman


#11
Why do you need to make shot first? Why not just pour an ingot?

The temperature needed to melt metal into an alloy is higher than
what’s needed to melt alloyed gold. I’m not sure if the high
temperature makes the grain structure too large or if there’s some
other resultant condition caused, but if you were to cast immediately
after mixing you would get a very brittle ingot that cracks
throughout. It’s necessary to alloy the metal to cool before using
it. Grain (shot) is the best form to melt metal in because the higher
surface area allows for quick, even heating. Faster melting equals
less oxide formation.

Larry


#12

Hi Noel,

David exactly wrote what I saw when a few days ago I alloyed 18k for
my first time. After the first melt there were parts of the copper
pieces still visible, so I had to re-melt the whole mass to get an
even mixture. So it is good advice what you are reading here. Good
luck with your first meltings; I really enjoyed trying it and the
results were nice, because I like the colour of my 18k. Still I would
not try it again and buy some shot the next time because it is a lot
easier.

Regards
Matthias