Hello
I'm wanting some time to melt some small pieces of gold I have
accumulated into some form of nugget to wear... at the moment I have it
in panned form in small flakes from Idaho. I have my own kiln and can
produce a reduction atmosphere if needed but just wanted to get some
advise from a few folk so that I don't make a mess of it! Anyone fancy a
chat about this sort of thing?
regards
Heather in England
Heather, Get a piece of wood charcoal ( Compressed Bricquets are my
last choice ) and drill or carve an indention deep enough to keep the
small flakes from blowing about. Use an Oxygen + Natural Gas , Oxygen
+ Propane , or even an Oxygen + Acetylene torch adjusted to a nuteral
flame . If you do not have a Oxy - Gas torch, take it to someone and
let them heat it. Heat with a flame large enough to melt but not so
agressive as to blow out the small flakes . When molten dump the gold
into water .
This should form a freeform nugget . Continue remelting untill you
like the form of the nugget . Pickle it in any acid water pickle or
alum water pickle ( 10 % solution ) Solder a 22 K or 24 K jump ring
for a chain and wear with pride.
Use a easy or medium 18 K or 22 K solder .
This Nugget is still native gold unless you add or remove anything .If
You intend to sell it, check with the UK hallmarking authorities
first.
Check Rec.Crafts.Jewelry on the Google groups or contact me off group
.
I can send resources easier via email, than I can over this group.
ROBB.
No need for oxy/anything. A plain old propane plumber's torch will melt the
gold just fine. Given the high gold content, I'd guess that pickling won't
be needed either. It's likely to be mostly gold with a bit of silver and
other metals mixed in, not likely to be much copper to oxidise on the
surface.
The easiest way to melt this metal is certainly on a charcoal block but you
should realise that you will not end up with a natural looking nugget.
You'll end up with a blob unless you carve some shape into the charcoal
block you melt it in. Even then, it won't a be a nugget. It's so easy to buy
gold and so difficult to pan it out of a river. If I were you, I'd keep the
flakes as a keepsake and buy some nice jewelry.
I used to melt down everything from flour gold, to ring cut offs. A "Burno"
crucible, as used in lost wax casting machines was used. These are
inexpensive, and avoid contamination. A propane torch was sufficient, as a
heat source.
Steve R.
Never, use 22 karat or especially 24 karat for a jumpring. Both are much too
soft, and will not last very ling. Use 18 karat.
Do not use easy or medium solder. Use hard solder.
Abrasha
Seems like good info - but I have a question (open to anyone for an
answer). I know gold is in different "qualities" i.e. 10K 14K 18K
24K, etc., and it's other metals introduced into the gold to change
the "K" of the item, correct? Questions are:
1. When melted, do all the impurities (other metals) float to the
top, sink, or what and how are they removed from the pure gold?
2. What is and how would you do "pickeling"?
Thanks
Ken.
no
no
they (usually copper, silver and other metlas like zinc, and/or nickel or
palladium for "white gold" )form an alloy with the gold.
Definition of alloy: a mixture containing two or more metallic elements or
metallic and nonmetallic elements usually fused together or dissolving into each
other when molten; "brass is an alloy of zinc and copper", "steel is an alloy
of iron and carbon"
This is done in a process called "refining". It is a fairly complicated and
exhaustive process, as well as very poisonous, because of the different
chemicals used. But in a nutshell this is what takes place:
DISSOLUTION: Acids react with gold, silver, copper and other alloy constituents
to form gold chloride solution, silver chloride precipitate and copper nitrate
solution.
FILTERATION: Silver chloride precipitate and insoluble matter is seperated from
solution containing dissolved gold and copper.
REDUCTION: Gold reagent, added to solution, reduces gold chloride to pure gold
oxide precipitate.
WASHING: Gold oxide is removed from the remaining solution containing dissolved
copper, is chemically washed and dried. You can now melt the gold powder and
re-use as required.
In the jewelry workshop, pickling is the process that removes oxides from the
gold alloy after it has been heated with an open flame for annealing or
soldering. Typically a 10% warm sulphurioc acid solution is used for it. Or a
more friendly compound (like SPAREX), which can be bought in granular form and
added to warm water. That is what I use for safety reasons, and because it
doesn't eat holes in my clothes.
WARNING!
If you contemplate making a sulphuric acid pickling solution, remember this:
AAA, ALWAYS ADD ACID!!! I cannot write this bold enough or add enough
exclamation marks. Never add water to acid, you'll regret it. If you're lucky
you'll only lose your eyes!
It's better and a lot safer to use a solution like Sparex, you don't have to
worry about acid explosions.
In goldsmithing school in Germany we were taught a rhyme to remember this:
Erst das Wasser, dann die Sauere.
Sonst passiert das Ungeheure
First water, then acid
Otherwise the "tremendously terrible" will happen
Abrasha
That mnemonic reminds me of a cautionary poem told by my science teacher
when introducing us kids to sulfuric acid:
Poor little Billy isn't with us any more
because what he thought was H-2-O
was H-2-S-O-4
Abrasha wrote:
You don't need any sayings or mnemonics for this.
The problem is simple, the dilution is exothermic. So
you put the stuff with the largest thermal capacity
there first, in the largest volume.
Thus any heat developed by the small droplets of
acid as they enter the container of water is
tempered by the large thermal mass of the water.
Doing it the other way causes local boiling and
spattering. :(
Jim
==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================
This just proves that you DO need those sayings AND mnemonics, because your
average goldsmith or person doesn't know about "exothermic" and/or "thermal
capacity". They are not scientists or chemists.
The "people" that I was being trained with in goldsmithing school were high
school aged teenagers.
Abrasha
Well. Nobody here anyway. The trouble
with all the cute-sy poems is sometimes
they get twisted around and you do the wrong
thing.
Jim
==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================
Hello again :-)
Thanks everyone for your various advise and comments...
Is there a main dealer of gold for using in jewellery who I can rely on
to supply me here in the UK should I go down that road instead of trying
to melt panned material. I'm still in two minds about melting material
or just getting something to play around with (typical fussy artist I
know... giggle). Obviously I can't afford to be ripped off. I work with
pottery but always fancied melting some gold... hence my original
question on this group.
I'm thinking there are probably lots of rip-off merchants in the gold
business, and especially on e-bay. Last thing I want to do is buy one of
those hallmarked sealed ingots only to find it's a something that's
really not worth the gold it's made of or has some fake hallmark on it.
Originally I bought my flakes from a main e-bay seller
"smoothstonesprospecting" in Idaho who appears to be reputible, it's
nice looking material with a rich colour and good weight, some small
visible impurites include bits of quartz, to be expected though. As far
as having a little hoard of flakes I'm very pleased with it but it's
working out cheaper to buy small flakes/dust than a single larger
nugget.
They told me that some of their buyers melt it and then quench in water
and bash it to remove the crust of waste material but they don't appear
to do much or any melting themselves so I did not get much advise from
them... they just pan it. Maybe I should just write to some of their big
bidders until I find someone who has used this material.
There's one dealer in the UK here I know of... "Exchange Findings" I
might have to contact them as they supply official material for
goldsmith's etc.
I have to admit I am clueless really! Is it better to buy gold from the
USA.
Another option I guess would be to try using some of that "precious
metal clay" that you can fire in a kiln but maybe that's cheating :-)
My original idea was to make myself a nice piece of good quality
jewellery to wear... I rarely buy custom made material because I think
it's more special to make it myself.
OK, enough for now.. just chatting.
regards to all
Heather
I dunno.... I kinda like the AAA always add acid.... Simple to
remember and pretty tough to screwup I mean it's not always add WATER
because that'd be AAW, which is what you would be saying if you did it
wrong.
Ken.
would just melt an old ring or two in the ladle, the skim off the
copper, zinc, etc., and then you would be left with pure gold to play
with... Figures - nothing can be simple.
Thanks for all the info - that was great.
Ken.
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