Hi
I’m trying to make a simple hammered band that is made from all my
scrap 18ct that I have gathered over time. I melt it then use the
rolling mill to square it up and taper the ends, then hammer it on a
steel block and a rounded hammer, but when it comes to bending it
into a ring it nearly always snaps. I am annealing it as much as
possible and using pliers to bend it as it is really tough, any
suggestions on what I’m doing wrong?
Ami
what is the scrap?
new wire/ sheet clippings?
old casting scrap?
what colour gold?
i’m no expert, but it sounds like you are work hardening the metal
and not annealing properly, maybe over heating the metal and making
it brittle? maybe under heating? annealing too much, quenching
instead of air cooling? here’s one article i retrieved from the net:
i’m setting aside some 18k for a similar ring, i’m going to use it
in a cuttlefish casting.
hth,
richard
I am annealing it as much as possible and using pliers to bend it as it is really tough, any suggestions on what I'm doing wrong?
The gold is contaminated with something, probably iron.
Tony Konrath
Ami,
Try making the ring first about 1/2 to 1 size smaller then needed.
Make sure the gold is annealed after bending into shape.
After the ring is made hammer it on a ring mandrel using a ball peen
hammer. The ring will expand in size as you are hammering it.
Good luck
Greg DeMark
my guess is that something got into the scrap or you used a crucible
not dedicated to gold. I had this happen once on some scrap I had
raised the karat of (18 to 22) that should have come out softer than
the original scrap and gold 9 yellow gold was used ). The only thing
I did differently that time was added one small bit of deoxidizing
master alloy from Hoover and Strong- it may have weighed 1/10th of a
gram and was for a royal yellow colour. I heated to anneal, then
roled after removing from the pickle and neutralising and then
rinsing, drying and a quick pass of tri-m-ite paper in about a 6
micron grit. I then hammered it on a stainless steel block and
reerolled it as I was going for a counter sunk looking hammered
texture.
I then annealed again and formed it. In using a leather mallet on A
55LB. horn anvil (CAST IRON) the damned thing broke. It was a rainy
day and a dim studio- at best! I realized when i examined it that
the metal was overheated and the crystalline structure was not
compacted correctly (overheating). I didn’t quench the ingot properly
and left it in the strong nitric pickle a little longer than
necessary and hotter than usual (accidentally a student turned it to
high that morning). So it was probably more brittle than it should
have been but being alsmost dark i didn’t notice the piece- but did
notice how light it felt in my hand (which should have tipped me off
in the first place!!!)
The other thing I did was to add my regular refining flux to the
fused silica crucible:three parts powdered charcoal to one part sal
ammoniac (available at a stained glass supply house cheaper than a
jewelry supply vendor). An old friend D. X. Ross and I used to often
discuss the use- or rather disuse- of brass brusing, iron anvils and
steel tools in the creation of precious metal jewelry and raw
materials in particular and how we both believed that some of the
iron (in the case of the anvil and swaging blocks, etc.)
contaminated work pieces or whatever one was forming. and in
remelting the stock scraps it contaminated it and made what would
ordinarily be a bright tough ingot into a rright extremely hard to
work ingot regardless of karat below 22. the sal ammoniac in the gold
refining flux (read Carles Codinade Arrmagnol’s", Goldsmithing" for
more on this flux) acts on the metal to aid in separating any visible
contaminants that can then be dipped of of the molten ball of metal
in the crucible with a graphite rod.
One thing I always recommend is to add at least 1/3 24 kt casting
grain to any scrap with whatever other metals or additives
(germanium for instance) are necessary for karat and colour desired
to scrap and if you have a good bit of scrap - more than 20 dwt., i
always recommend to students to use solder disclosing solution,
spray, powder- whatever the form if its scrap you did not generate
and acan recognize and account for. you never know what someone
before you did in repairs, sizings, etc. or what exactly they used.
Soto avoid brittle ingots, breakage, splitting, poorly structured/
repacked crystals in the ingot always know whats in it ! A magnet
will also be a handy thing to keep in your sweeps or scrap tray. etc.
to reveal iron from saw teeth etc., or old solders tthat weren’t
plumb, and the flux glass contaminants in a non dedicated crucible…
So I hope those give you a few points to think about. I would remelt
the gold if it’s reclaimable, in a new crucible, well glazed with
crystalline borax (perrhaps from filings off a traditional borax cone
if you have no other borax in the studio) add 50% new 24 karat
casting grain or otherwise new 18 kt gold and copprr, silver,
cobalt, chromium, etc. for yellow to olive green! - then quench in
water after it air cools to grey. Then work from there. good luck!
If you need any colour recipes feel free to contact me off list and
indicate the colours you are leaning toward. Best regards… rer
Trouble with using scrap for doing forged work is that the alloy
must be suitable so it looks as though some of your scrap was a
casting alloy. This invariably contains a small amount of silicon
which doesnt take kindly to being rolled and bent much. Only way to
get rid of the silicon is to cupellate your gold, which will mean
that you will have to weigh it very accurately before and after so
you can then add a small amount of copper to keep it at 18ct.
Nick Royall
Trouble with using scrap for doing forged work is that the alloy must be suitable so it looks as though some of your scrap was a casting alloy. This invariably contains a small amount of silicon which doesnt take kindly to being rolled and bent much. Only way to get rid of the silicon is to cupellate your gold
Nick, could you post instruction on cuppelation in the studio?
Tony Konrath
You have probably got some contamination in your gold. either too
much solder or there has been a tiny piece of iron, say, a spring
from a boltring from an old chain. It only takes a minute piece of
iron in the melt too ruin gold or silver.
You could try a refining flux, either a commercial one or recipes in
Marion’s Metalwork and Enamelling or Oppi.Try Amazon. I am sure there
would be something in Ganoksin libraries. It involves chemicals used
in explosives. So I wont go into details. I did hear recently
someone here who had left some dodgy gold in an electric melter with
a carbon crucible for far longer than usual by mistake and it was ok.
when he pored and worked it. You may just have to have it refined.
Also you dont need to anneal every two minuets. prepare the metal
with the rolling mills to a little thicker than you want and a
little narrower and make a thicker plain ring then hammer the texture
while bringing the ring up to the size you want. Makes life much
easier.
David
jewellerydavidcruickshank.com.au
I agree with the person who said you’ve probably contaminated your
gold. You can refine it by parting. I rewrote a recipe for parting
(and used to sell it on eBay). I’m sure some of the older, more
schooled folks on here will find much wrong with it.
Read the disclaimer!
I agree with the person who said you've probably contaminated your gold. You can refine it by parting. I rewrote a recipe for parting (and used to sell it on eBay). I'm sure some of the older, more schooled folks on here will find much wrong with it.
It is pretty much the standard process it is also called
inquartation. The only real question I have about your version is why
use silver to dilute the gold, copper will work just as well.
Also in the step where you reclaim the silver, the white precipitate
formed when you add the salt is silver chloride. Silver nitrate is
water soluble and is what is formed when the nitric acid dissolved
the silver out of the alloy. By adding the salt you cause the sodium
to replace the silver in the solution and the silver combines with
the chlorine to make silver chloride which is not water soluble so it
falls out of solution.
I know you have lots of caveats in your article about the dangers
involved but it is an extremely dangerous procedure and as you point
out life threatening. It is also an expensive way to reclaim your
gold, 1 gallon of concentrated nitric acid (60-70%) costs more than
$200 before shipping and Hazmat shipping costs will add $50-$100.
Typical costs from many refiners for 1 oz of gold is quite a bit
less typically less than $100.
James Binnion
James Binnion Metal Arts
It is pretty much the standard process it is also called inquartation. The only real question I have about your version is why use silver to dilute the gold, copper will work just as well.
Have you ever tried to melt five troy ounces of copper?
Also in the step where you reclaim the silver, the white precipitate formed when you add the salt is silver chloride. Silver nitrate is water soluble and is what is formed when the nitric acid dissolved the silver out of the alloy. By adding the salt you cause the sodium to replace the silver in the solution and the silver combines with the chlorine to make silver chloride which is not water soluble so it falls out of solution.
See? I told you some smarter folks would call me out.
I know you have lots of caveats in your article about the dangers involved but it is an extremely dangerous procedure and as you point out life threatening. It is also an expensive way to reclaim your gold, 1 gallon of concentrated nitric acid (60-70%) costs more than $200 before shipping and Hazmat shipping costs will add $50-$100. Typical costs from many refiners for 1 oz of gold is quite a bit less typically less than $100.
I buy it locally. It’s a lot cheaper. I use a different method now
too. BTW, I never got more than a buck for it on eBay. You get what
you pay for. 