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Melting gold


#1

Help. Does anyone have tips for melting and pouring gold
successfully? I usually melt 10 grams or so. And its when I pour it
into the iron strip, it kinda goes all over the place. Should I put
flux into the ingot first to help it flow.or pour slower?also years
ago I remember we used to put a scrap of another metal into the mix
to help it stay together.cant remember what it was, zinc maybe? But
what does that do to the carat? Thanks for any tips and pointers.
Bob


#2
Help. Does anyone have tips for melting and pouring gold
successfully? 

Go to my website and check out the video Frugal Goldsmith.

Leonid Surpin
www.studioarete.com


#3

Bob, I’m not sure exactly what you mean by it kinda goes all over
the place? One tip is that when I use an ingot mold I heat it up hot
enough for it to melt wax. The guy who trained me used 3-in1 oil and
heated it until the oil smoked. The idea is that the mold needs to
be warm and seasoned for the ingot to flow nicely and to release
after poured. Hope that helps a little bit.

Mark


#4

Lawrence,

First, I’d ditch the strip-type ingot mold. You are right, it’s
really hard to get anything like a consistent thickness, or even a
good ingot. Try buying a combination ingot mold, which allows a
vertical pour. You’ll find the metal “compacts” into the vertical
mold, making a very even shaped ingot, of either round wire or any
width of sheet. I think it will be a lot more versatile and easier
to get a good ingot. Be sure to pre-heat your ingot mold before
pouring, use a robust heat source, and pour right through the flame.

Have fun!
Jay Whaley


#5

Hi Guys,

Use some delft clay to make your ingots, sheet and wire.

The reasons to do this :-

  1. You don’t need top heat the mould, and can be used instantly.
  2. You can make the sheet, ingot and wire finer than any steel
    mould.
  3. If you stuff up, you can reset really quickly.
  4. Preparation of the mould is very easy and very quick.
  5. The metal in contact with the clay will be bright and clean.

The reason not to do this :-

  1. Delft clay isn’t cheap.

  2. Delft clay is a consumable, unlike a steel mould that lasts
    forever, so you will need to buy more on occasion (mind you can get a
    lot done before you need to do this).

Give it a go, there’s nothing to lose.

Regards Charles A.


#6
Go to my website and check out the video Frugal Goldsmith.
http://www.ganoksin.com/benchtube/video/688/Frugal-Goldsmith 

What’s the purpose of “forging” with the hammer before rolling?


#7

Hi Guys,

Forgot the main reason for using Delft clay for ingots.

The crystaline structure is uniform through the ingot. It makes it a
breeze to roll.

In a steel mould the grains closest to the steel are tight due to
rapid freezing.

Regards Charles A.


#8
First, I'd ditch the strip-type ingot mold. You are right, it's
really hard to get anything like a consistent thickness, or even a
good ingot. Try buying a combination ingot mold, which allows a
vertical pour. You'll find the metal "compacts" into the vertical
mold, making a very even shaped ingot, of either round wire or any
width of sheet. I think it will be a lot more versatile and easier
to get a good ingot. Be sure to pre-heat your ingot mold before
pouring, use a robust heat source, and pour right through the
flame. 

I would add: Use the soot from acetylene (no O2) as a release before
clamping the mold together, and also you can make 1/2rd ingots as
well.


#9

Lawrence,

The problem you are having most likely is that you are not heating up
the ingot former first. The ingot former is most likely cast iron
which can hold a lot of moisture. When hot metal hits the cold moist
cast iron it splatters.

Hold a torch to the ingot former a until you see the moisture come
to the surface and dissipate. Then you will be able to pore your
gold without the splash back. Some jewelers also like to coat the
ingot former with carbon to help get a better ingot.

Good luck
Greg DeMark
http://www.natureinspiredjewelry.com


#10
http://www.ganoksin.com/benchtube/video/688/Frugal-Goldsmith What's
the purpose of "forging" with the hammer before rolling? 

I’d be interested to know also, as my ingots have an even grain
structure, and I can shape them to whatever shape I need prior to
rolling.

Is the cold forging required because you use a steel mould and the
grain structure is inconsistent? Just curious.

Regards Charles A.


#11
What's the purpose of "forging" with the hammer before rolling? 

Right after casting, metal grains much larger than they should be.
Forging breaks it down into fragments, which upon annealing
re-crystallize into smaller, compact grains. This is one of the
principal differences between handmade and cast jewellery. Metal
prepared that way is much stronger and retain polish longer, if
fabrication proceeds with direction of the grain in mind.

In my DVD “Eternity Ring” this principal observed very stringently.
It allows creating of the structure, which look very flimsy, but
actually much stronger that it’s casting counterparts.

Forging step can be avoided if one has industrial mills. First pass
should be 1/3 of ingot thickness, followed by multiple small passes
rotating ingot 45 degrees each pass, until only half of the original
thickness remains. After first annealing, rolling should resume in
normal fashion. Not as good as hand forging, but acceptable. This is
only possible with very large mechanical mill.

Leonid Surpin
www.studioarete.com


#12

Hi everyone,

I am also having problems melting gold. I tried melting some 24k
casting grain on a carved-out section of a charcoal block, using
propaine-air. I couldn’t get the grain hot enough to melt together.
Is it the torch? Is it the charcoal? Is it both?

Thanks,
Jennifer


#13

i’ve never forged ingots before rolling, and i’ve been successfully
rolling out sheet and wire stock for many years. however, leonid
surpin used to be a goldsmith with tiffany in new york, and he is
the very definition of a master goldsmith. he’s got the experience to
back up his technical skills.

…and i’m always ready to listen to any ideas which will improve my
skills!

jay whaley


#14
i've never forged ingots before rolling, and i've been
successfully rolling out sheet and wire stock for many years. 

It doesn’t mean that one can not produce jewelry without forging.

As explained by others, forging gives a much better grainstructure
to work with. The metal will be much compacter, much harder. Jewelry
will last longer and a perfect finish will possible after forging.

However, keep in mind that pounding with a hammer on metal is not
forging in the meaning of creating a better grainstructure. Many
"small hits’ are better than one big blow and THAT is one needs to
learn and take care of.

Forging is time sensitive and will raise laborcosts without any
dought. As shown in Leonids video, it needs to be done in four
directions. I like to use a ball hamer sheape instead of a regular
metalsmith hammer.

As novice jewellers learn how to file, saw and poor metals, they
should be educated how to forge properly.

Pounding with a 1/2 kg hammer on metal and reducing the size is easy
but having the same tickness allover is another ballgame. More then 80
percent of the student I’ve worked with don’t forge their metal. A few
of them do but do not know how to perform it correctly.

I asked once why people don’t forge their metal and surprisingly the
majority answered that they don’t see the need of it. Other estated
that forging is an annoying and loud process which takes a lot of
time. After explaining why and how it should be done, students still
don’t want to forge their metal because of the second reason above.

It gives somekind of a direction whe are going to to my opinion. Gold
and silvesmithing is more then creating jewelry. People are more
looking into getting money for their product instead of understanding
how to work on metal to create jewelry. Make it and sell it… next
job.

Anyway, I’ll keep on forging and telling about the importance of the
process. If others chose to not, well that’s up to them. Am I a
better jeweller? I don’t think so. Am I a knowledgable jeweller, yes,
without any dought but still I don’t know everything and their will
always be a gap for more knowledge.

Pretty long mail to encurage the forging process but it makes a
different.

Enjoy and have fun
Pedro


#15
Forging step can be avoided if one has industrial mills. First
pass should be 1/3 of ingot thickness, followed by multiple small
passes rotating ingot 45 degrees each pass, until only half of the
original thickness remains. After first annealing, rolling should
resume in normal fashion. Not as good as hand forging, but
acceptable. This is only possible with very large mechanical mill. 

I do it slightly differently.

I roll my ingots down to 1/3, then I anneal the ingot, roll again,
until I get the desired thickness. Mind you I usually cast my ingots
closer to the final size required than a steel mould.

I can do this with hand operated rolling mills. It does take longer
than using the electric rolling mill, but I enjoy it more :wink:

Hand forging sheet is okay as long as the sheet size is relatively
small, you wouldn’t want to beat a relatively large sheet (like they
used to in Ancient times).

Regards Charles A.


#16

I forge all my ingots before rolling. I was originally taught that it
was important to hammer the whole surface of the ingot at least one,
but I’m not sure if that’s the case or not; what I tend to do is
forge the top and sides, but leave the ends untouched - this yields a
billet with nicely rounded, convex ends, which go easily into the
mill, and end up needing less filling to prevent them going concave.

The overall reason I forge the ingots is to get them to a more
appropriate shape - take a couple of mm off the cross-section, and
shift them from a square into a diamond, which then goes really
neatly into the mill, and doesn’t tend to flange as much at the
sides. The ingots are cast in delft clay or on a fabric sling in
water. This is pretty much a daily routine, in a wide range of alloys
in silver, gold and platinum, casting anything from a couple of grams
to half an ounce.

Jamie Hall
primitivemethod.org


#17

Hi Jennifer,

I am also having problems melting gold. I tried melting some 24k
casting grain on a carved-out section of a charcoal block, using
propaine-air. I couldn't get the grain hot enough to melt
together. Is it the torch? Is it the charcoal? Is it both? 

You can melt gold copper and silver very easily using propane +
atmospheric air.

I know that when you hear me say this you will feel disheartened (as
I did when I first started down the road of melting metal).

A small hand held propane torch cylinder is all you need, but you
will never be able to melt 24k in an open crucible with that torch.

The way you melt metal with relatively low powered torches is to
contain the heat.

You can achieve this by building a micro furnace body to accept your
torch, and you do have to use bilge type crucibles. Open crucibles
are too inefficient for melting gold.

The only other solution is to get a hotter torch, then you can melt
metal in an open crucible.

Regards Charles A.


#18
Is the cold forging required because you use a steel mould and the
grain structure is inconsistent? Just curious. 

Yes, and if you want the best quality you should scalp (remove) the
outer surface to get rid of any metal/mold reaction products.

James Binnion
James Binnion Metal Arts


#19
Right after casting, metal grains much larger than they should be.
Forging breaks it down into fragments, which upon annealing
re-crystallize into smaller, compact grains. This is one of the
principal differences between handmade and cast jewellery. Metal
prepared that way is much stronger and retain polish longer, if
fabrication proceeds with direction of the grain in mind.

I’ve been contructing jewelry (what you refer to as “handmade”) for
over 30 years and have never down this. I’ve also never had the
problems this supposedly prevents.


#20
I've been contructing jewelry (what you refer to as "handmade")
for over 30 years and have never down this. I've also never had the
problems this supposedly prevents. 

This is not a new debate. To forge or not to forge has been around
for many years. Forging improves crystalline structure. That is a
fact. If you do not think that it is worth half an hour of your
time, than you should not do it.

Leonid Surpin
www.studioarete.com