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Gold alloy is cracking


#1

Hello All

this question I have is for the experts in metal alloy ingot making
and drawing.

I have been having a lot of problems cracking of the metal, the
minute I start trying to work it. the metal i have is 14k Yellow, I
know I have used it a few times over, with out adding fresh metal to
it and so I believe it is at it’s end of use as is. for 3 days on and
off I melted adding some new material to it and the minute I would
start forging/rolling to square wire it would crack like crazy, a few
times I repaired by fusion, and it worked for a 2 grooves down the
line, but would start cracking again. and this is with annealing down
every groove.

I noticed that when i was quenching as normally I would 14k Yellow
in alcohol it was cracking,so I started waiting for it to cool down
almost completly before quench, it helped.

I know the best thing to do is give it up and turn it in for
refinning. but with that I will be loosing out finnancially.it is an
ounce of 14k.which is worth a certain amount given in, and to
replace it I will probably get only half an ounce if not less.

I know that there are ways to fix the problem of cracking when the=
alloy is too abused/used. even with new metal being added it did not
fix the problem, but I am thinking that I added only a quarter of
the amount needed to replenish(that’s all I had). so my question is
to take care of the brittle metal if I were to add the same amount
(1 ounce)or more of new metal to the batch would that solve the
cracking issiue or would it make thewhole batch bad and brittle?

My follow up question in this is, in the US. where would one be able
to buy pure gold in Bullion form? not the refined casting grains.
was there a place that sold smaller tablets/bullions? I remember
back home and europe it was available from any bank, you could walk
in and purchase a smal amount of coin or tablet of pure gold. most
goldsmiths did that who made their own alloys.

thanks for your attention, any advice would be appriciated, hoover
and strong, stuller, United metals, PM west, anyone from the
refiners advice is more then welcome too.

Hratch


#2
to replace it I will probably get only half an ounce if not less. 

NTR Metals will give you 98% of the 24 kt back. Coin dealers will
have pure gold in 1/4, 1/2, and one ounce ingots. NTR sells pure
gold grain for $5 over spot, any amount you need.

Richard Hart G.G.
Denver, Co.


#3

See me Tue. bring your metal.


#4
I have been having a lot of problems cracking of the metal, the
minute I start trying to work it. the metal i have is 14k Yellow,
I know I have used it a few times over 

I am going to assume that your have read recent discussion on
forging ingots.

If forged ingot still cracking during rolling, we have to entertain
the possibility that gold has been contaminated. I can suggest the
following procedure to attempt to remove contaminants without
resorting to refining. If it fails, than refining should be
considered.

For every ounce of alloy use 10 grams of potassium nitrite and 20
grams of borax. Do not mix them together. Melt your gold without any
flux. Metal will oxidize but that is what you want. When liquid, add
potassium nitrite. Do it under the hood. There will be a lot of
nasty smoke. Keep heating the crucible shaking it all the time.
After 5 minutes or so add borax. Bring everything to pouring
temperature and cast in water from at least 6 inches high. It is
important to keep crucible high above water. If even droplet hit the
crucible, you will have very memorable experience, and very costly at
the same time. Crucibles have been known to explode under these
conditions, sending molten metal in all directions.

Step 2. Collect your gold with should be in granules and wash it
from flux. Remelt it normally and forge to at least 2/3 of thickness
before rolling. For second melt use new crucible. Potassium nitrate
damages crucibles, so it has to be the remedy of the last resort.
Use dedicated crucible and examine it every time before using.

Leonid Surpin
www.studioarete.com


#5

Try the oxygen burn-out trick. You need an oxy-acetylene cutting
torch to do this. The cutting torch has a button that when pressed
will deliver a huge surplus of oxygen.

Melt your gold alloy with the cutting torch and when molten press
the cutting button for 5 to 10 seconds while directing the flame into
the melt. Your alloy will superheat, bubble and boil, as the
impurities are burned out. This will include any zinc, lead, tin etc
that may be making your alloy brittle. Definately have a good
extraction hood while you do this, as with any melting! Let the
molten puddle cool to normal melting temp, add a pinch of borax, and
keeping it molten with the torch…pour.

Your alloy may be a higher carat than when you started because some
of the copper will have burned out, but in most cases your alloy will
behave much better after this treatment.

Alastair


#6

Hello,

Fischer in Germany has a well proved melting powder (based on
potassium nitrate) which I’ve been using for years. Add the powder 1
to 1 to your gold and let it melt in a furnace. Follow the
instructions and your gold will come out as a brandnew mix. The
product is rather cheap (about US25$ per kilo) and no further
refinning costs!

http://www.ganoksin.com/gnkurl/ep7zgs

Have fun and enjoy
Pedro


#7

WOW! Thank you to all who responded, have not acted on the metal yet,
I think Leonids definition and explanation is fantastic, did not know
about the Potassium nitrite technique, also thanks to Pedro for
mentioning it from Fischer. depending on how easy it will be to
purchase the Potassium nitrite, i did see offers on Ebay and amazon,
was there a difference between that material and what is being sold
at Ficher in germany. there are huge price differences per pound.

as to the forging of the ingot, I was following that thread,and I
forged my ingots into sheet and wire for a long time before
purchasing my mills (15 years), but I do forge them minimally to
shape before my milling begins.

I do like the idea of the last resort/ trial to clean up the metal,
but am not sure about the health hazards vs the costs of refining
balancing act. But the info sounds fantastic. Larry I will pass by
and bring the metal with me,it is thursday, I just got your message.
My suspicion on this matter is that the mix of alloys over time has
gotten some materials in it from different sources, like deoxidisers
and silicone? that may be unbalancing the alloy. " it isn’t my
fathers generational alloy any longer where it was gold silver copper
and perhaps at worse zinc".I am also wondering about the crucible
contamination,I guess it may be possible that it had contaminants in
there? even though in my shop I have strict rules about NO mixing
crucible use, ever. but I can only guess.thank you all, I will get
some potassium nitirite (I welcome any advice on the point of
purchase), but will have to setup outdoor to do the cleansing.

Hratch
Atelier Hratch Babikian
contemporary Jewelery and sculpture


#8
i did see offers on Ebay and amazon, was there a difference between
that material and what is being sold at Ficher in germany. there
are huge price differences per pound. 

The idea behind the technique is that potassium nitrate is a very
strong oxidizer. Once oxides are formed, they need to be removed from
the melt. Compound sold by Fisher may have additional elements to
improve efficiency if forming and removing oxides, or may not. I
never worked with it. But if it does, it may explain the difference
in price.

Leonid Surpin
www.studioarete.com


#9
My suspicion on this matter is that the mix of alloys over time
has gotten some materials in it from different sources, like
deoxidisers and silicone? that may be unbalancing the alloy. " it
isn't my fathers generational alloy any longer where it was gold
silver copper and perhaps at worse zinc". 

Incredibly tiny amounts of iron or lead can cause this behavior.

James Binnion
James Binnion Metal Arts


#10

thought you might want to know

So today i finally had time to get to Larry, at Larry Paul Castings,
and as he had said he would help with this metal cracking, He Did.
Larry thought that the metal would not need the potassium nitrite
conditioning, and basically he remelted the 14k in a graphite
crucible, but under argon gas and a mixture of another. poured into
a metal ingot mold, did it twice, I got home and rolled the metal in
my square stock mill ; to a very pleasant surprise did not need
annealing and did not crack, beautiful metal, it stayed soft as
butter for the first 2 grooves and have not gone further yet but I
suspect it will continue on for another groove with out annealing.
WOW ,

So basically it was the heat source that was causing all the
brittleness in the metal by adding more oxygen and carbon into the
metal, (I use oxy acetylene) been useing this type of gas for 30
some years, but it only takes once for me to start looking for better
fuel. So Larry Paul, saved my day and metal,that was a very nice
thing he did. thanks Larry,good karma right back at you.

Hratch
Atelier Hratch Babikian contemporary
Jewelery and sculpture


#11

Hello Hrathch,

Larry Paul solved my casting problems when I was doing my own
casting, meaning he was kind-enough to help me with my casting
problems. Sooo! Larry has been doing “ALL” my castings and with
Perfected Results.

When there is someone with his Knowledge, Talant, and Skills."I"
will yield to the best in his business and to the considerations he
has shown me for many years.Larry is by-far the The most
considerate, non-assuming, grateful person, “Master-Caster” that I
have known for 30 + Years.

Stephen Wyrick, CMBJ