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Melting impurities out


#1

Hi!–Gary here-I have been goldsmith for 40 years & have always use
potassium nitrate (salt peter) to clean old solder & other impurities
out in the crucible. Now salt peter is on the explosive list it is
impossible to get. Has any body found an alternative? please adivise


#2

Now salt peter is on the explosive list it is impossible to get.

It is still used in Veterinary medicine… And while I am in Canuk
Land, not the land of the Department of Homeland Insecurity, it is
almost impossible to get trough ‘normal’ channels here too, but I can
still buy it in pound bags at the local Agricultural supply store.

Kay


#3

I’ve seen it in our local feed store as well. I think it was in the
’bovine’ section. I remember seeing it last week while searching for
wormers.

Dinah


#4

Can’t help with a source, but you brought up a memory of purchasing
saltpeter at the local drug store, then having to go to another store
to get my charcoal and sulphur to make black powder in my basement. I
also made my own little cannon to shoot the stuff with.

John


#5
Now salt peter is on the explosive list it is impossible to get.
Has any body found an alternative? please adivise 

check amazon. I just bought a pound couple of weeks ago.

Leonid Surpin
www.studioarete.com


#6

Hello,

Has any body found an alternative? please adivise" 

A well knowen product amongst many goldsmiths, know about
auropurifax Te same kind of product exist for silver and is named
argoflux. http://www.ganoksin.com/gnkurl/ep7zrp

Both are rather expensive but they do the cleaning job very well.

Another item carried by Fischer in Pforzheim is melting powder.
http://www.ganoksin.com/gnkurl/ep7zrq

I don’t knwo which company carries this product except the one I
mentioned above.

These products ar legal, there is nothing wrong with them.

Have fun and enjoy
Pedro


#7

If anyone has not mentioned this yet there is wood charcoal and then
there is bone charcoal if you are using wood charcoal to make your
melting flux you are wasting your time and metal. Make some bone
charcoal easiest and least offensive is made with poultry leg bones
(thanksgiving is this week) you can do this with the same methods as
making wood charcoal but don’t over burn them, if they turn white
the charcoal is turned into something else. Grind up the charcoalized
bone with a mortar and pestle and add to borax and or boric acid.
Ammonium chloride is another chemical that can be added to melting
flux to remove impurities but this is only needed in extreme
circumstances, which if the metal is that bad you should really send
it to the refiner. I have purposely not been too specific about an
exact recipe here because what is important is that you experiment
and learn through this process. If you dont know how to make
charcoal look it up I dont need to waste the moderators time
explaining a simple process. I do however make mine with an acetylene
/ air torch on a fire brick outside. There are a bunch of people who
will read the words ammonium chloride and panic they may reply with
lengthy discourses on safety. I am betting that all of you who read
this have enough common sense to already know, since you all work
with dangerous stuff every day, that when you do things that cause
fumes of any kind that process is performed with adequate means of
ventilation in place - goo


#8
Can't help with a source, but you brought up a memory of
purchasing saltpeter at the local drug store, then having to go to
another store to get my charcoal and sulphur to make black powder in
my basement. I also made my own little cannon to shoot the stuff
with. 

Yeah, me too. Made good sized rockets which sometimes turned out to
be roman candles.

Remember one going off course and chased my dad while he was runnibg
up the street to get away. Was funny.

Eric


#9

I find pure oxygen does the job. Melt the alloy then introduce a
stream of oxygen. The oxy-acetylene cutting torch is designed to do
this. Anything that oxidises will oxidise leaving behind the elements
that refuse to oxidise…gold, silver, and the platinum family.

Burning the oxides creates super high temps; let the melt cool down
before adding borax flux which will sweep up the products or
residues of the oxidation.

Alastair


#10

Hello,

lot’s of fun with sterling silver!

Have fun and enjoy
Pedro