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Silver gold overlay best techniques


#1

Hello Every Body

I would like to make a tube hollow necklace from a tube: length is
40 cm.

thick is 1mm of silver which is gold overlaid (.2mm)-

1- Before making sheet with rolling mill, what will the size of the
ingot.

2- What is the best silver and gold to overlay each other?

3- Is ther any special recommendation about annealing? (starting to
anneal after 50% of the thickness reached form rolling? sterling with
18K or pure silver with pure gold?

4- Can we make gold overlay sheet with no flux and solder, just
heatin to red before using rolling mill?

5- Which kind of solder for the seam?

6- Is ther any special book about gold overlay techniques on
precious metal?

I know, there is a lot of questions here, but I dare, it is my
birthday on 22 April.

THANK YOU FOR ALL THE REPLIES
BEST
Nathalie


#2

*it does seem like it would be a rather simple process : * which
comprises a step involving fabrication of a first hollow element in
tubular form, made of precious metal or a precious metal alloy and
intended to act as" a lining;and then preparation of a second element
in cylindrical form made of metal or metal alloy, or precious metal"
in your case and " intended to act as a core for said first element
in tubular form; a step involving coaxial combining together of the
two elements by interposing a layer of solder in between so as to
obtain a tubular assembly which is then subject to a first drawing
step aimed at compressing the first element onto the second element;
Followed by a step involving brazing of the tubular assembly so as to
melt the layer of solder and fix together the two elements before a
second drawing step for reducing the thickness of the brazed tubular
assembly to the desired value is reached…"

But its not as simple as it sounds and requires more specialized
equipment than a drawbench and furnace /kiln along with some
calculations based on the liquidus properties of each to prevent a
meltdown of the silver - or rather the silver seemingly 'absorbing"
the gold layer before even adding a metal alloy /solder layer between
the two to help prevent this. All to make a relatively small amount
of stock. and that’s just the most immediately probable issue you’d
experience at the cost of a fair amount of gold and silver sheet.
Even if you used lengths of tubing of gold and added a layer of
powdered solder suspended in a gum or other binder and then a length
of silver as an “insertion wire” with a graphite or otherwise
non-conductive material as a core to keep it all from collapsing when
heated and hoping at the precise temperature the solder melts and
bonds the gold that is no where near liquidus, but has heated enough
to bond to the silver insertion tube, which couldn’t be as thin as
the O. D. normally supplied by vendor and finding the right i. d.
graphite, magnesium, or some ceramic composite rod ( imagine a long
length of mechanical pencil lead in the exact core size and length
necessary to fit the assembly which is now four layers that all have
to remain perfectly intact, not move and - well, stay put in the kiln
perhaps in a pile of alumina to prevent movement…) You would need to
buy a fair amount of it for the trial and error it will surely
require.!.

It would be far easier to simply purchase bi-metal sheet, anneal it
very carefully (math required or a conversation with the tech person
at the manufacturer that sells you their bi-metal sheet as to the
annealing time at x temp for x gauge and in your case without
coaxial pressure)…Then forming it into a tube and then drawing the
tube to the desired thickness and length. the bi-metal sheet would
already be bonded., and joining the seam straightforward if gold,
rather yellow silver solder is used to close the seam as the gold
temp. wouldn’t be an issue if you carved the metal sheet into a lap
joint (removing with a sharp graver or other tooling the gold on a
bevel to have a silver to silver seam which could be closed with
yellow silver solder and the tube resulting appearing all gold on the
outside and silver inside…

If 40 cm is needed you could probably triple that amount of raw
materials just for the trial and error experimentation of making
your tubing in the small studio.

i don’t quite understand why the id has to be silver though unless
you are going to engrave it, or carve, etc. If it’s for slicing off
some pieces for tube settings there are easier ways to do that too! I
suggest your looking at the patent info and equipment that you would
need access to to accomplish it successfully. patent. EP 1679015 A1.

  • pertains to the methodology involved in and problems related to
    making tubular bi-metal for jewellery. it may seem technical but many
    questions you ask are answered in the application’s abstract…

It is not that it is impossible but that you could far more easily
buy 40cm + of bi-metal sheet than finding the **equipment necessary
to make the metals bond to the core and then convincing the equipment
owner(s) to let you have a go at it on their equipment in their
space/factory. and where is that factorye there are a lot of things
you perhaps haven’t thought of ! At least, if you have strong hands,
a decent drawbench set-up (or an electric winch) and some bi metal
sheet, you could draw down the tubing. But the process isn’t
something i’d let even an intermediate student attempt- particularly
if I had to watch! You can do it- I can’t figure out why you’d need
silver as an lining unless you’ll embellish the tube once drawn…

I also don’t want to discourage your experimentation, but perhaps
you have available funds and money isn’t an issue- in which case, a
bi-metal sheet is generally supplied in 12 inch (one measurement) or
6 inch size **s and working with the bond already done seems like the
right way to start. Good luck. rer


#3

So what patent did you copy and paste this info from?

*it does seem like it would be a rather simple process : * which
comprises a step involving fabrication of a first hollow element
in tubular form, made of precious metal or a precious metal alloy
and intended to act as" a lining;and then preparation of a second
element in cylindrical form made of metal or metal alloy, or
precious metal" in your case and " intended to act as a core for
said first element in tubular form; a step involving coaxial
combining together of the two elements by interposing a layer of
solder in between so as to obtain a tubular assembly which is then
subject to a first drawing step aimed at compressing the first
element onto the second element; Followed by a step involving
brazing of the tubular assembly so as to melt the layer of solder
and fix together the two elements before a second drawing step for
reducing the thickness of the brazed tubular assembly to the
desired value is reached..." 

James Binnion
James Binnion Metal Arts


#4
I also don't want to discourage your experimentation, but perhaps
you have available funds and money isn't an issue- in which case,
a bi-metal sheet is generally supplied in 12 inch (one measurement)
or 6 inch size **s and working with the bond already done seems
like the right way to start. 

From here in the UK, the following experience may be of interest.

Many yrs ago one of the products I was making was a deep transparent
ruby red enamel on fine gold.

When gold was $32. dollars an ounce I still needed and wanted a
still lower metal cost.

The need was for a bi metal strip of 1/1000 gold over 9/1000 in.
fine silver.

I talked to Johnson Matthey in Hatton Garden London and they were
happy to make this for me in 3in wide strip by 36in long.

They start with a short block of the 2 metals soldered together,
then roll it out to the final thickness the customer needs.

Bi metal and tri metal sheet has been around a long time, Sheffield
plate was the first commercially available material of this type, as
silver copper silver.

I have a nice example of this in a tray.

Get it made, then turn it into the tube section you need. Time is
money!!

hope this helps.
Ted.


#5
I would like to make a tube hollow necklace from a tube: length is
40 cm. thick is 1mm of silver which is gold overlaid (.2mm)- 

With the right equipment this is not too difficult to do. You would
either make or buy bi-metal (gold fill) sheet and using a BonnyDoon
hydraulic press or similar tool draw the sheet into a cylinder then
continue to draw it to the desired diameter and length with a draw
bench and draw plates. I make seamless multi-metal tubing like this
in my studio. Without those tools the easiest thing would be to buy
bimetal from Reactive metals or Hauser and Miller and solder it into
a tube and then draw it to size. In either case making 40cm of clad
tubing is not too hard to do but definitely not a quick beginner
project.

To learn how to make your own bi-metal look at the books and
internet references on mokume-gane. This process will allow you to
make simple two layer or multi layer laminates. Once you have the
laminate the rest is fairly basic metalsmithing work.

James Binnion
James Binnion Metal Arts


#6

Interesting

http://www.ganoksin.com/gnkurl/ep805w [p925.com] is promoted by the
Thai government.

I would have thought the expertise of Thai precious metal smiths
would have been the first port of call.

This just shows how important and useful Orchid is. A global
resource like no other.

However a customer who bought a ring from me that needed sizing
down, was traveling to Asia before I could do it.

He was going through Thailand and I said great place to have it
done.

“No way they are not good anymore, I will get it done in Laos.”

Was this guy looking in the wrong places in Thailand? Or is it
basically tourist trade like Indonesia these days.

What the Thai silversmiths used to do raising giant bowls was truly
amazing. Also my mate Chad, a Thai,

sold the most amazing quality jewellery from Thailand about 30 years
ago.

Are they losing the bench skills like we are in the west?

Richard


#7

Mr Richard

http://www.ganoksin.com/gnkurl/ep805w [p925.com] is promoted by the
Thai government. 

a promoted thai factory means that our customers are assured we do
not employ any children and that our staff has very good working
conditions similar to european workshop. in Laos, i’m not sure. may
be.

Thank You to all members of orchid who have given us their advices.
we are a small workshop and will learn again and again and will
share…

best
nathalie


#8

Hi Nathalie

I wondered about Laos, too, as Thailand is famous for quality
jewellery.

Yesterday I was chatting to a gem supplier for Tiffany, 50 ct
sapphires etc.

He was surprised that my customer preferred Laos over Thailand as he
has always found Thai quality to be superior over all others in SE
Asia.

I think my customer had just had a bad jewellery experience in
Thailand.

It is good to see what government endorsed businesses mean in
Thailand.

However still throughout Asia work health and safety compliant
workshops are rare.

But I have refused to work in some very sub-standard work shops in
Australia.

I went to one job interview in a resin casting factory, to the boss I
gave an expletive deleted, he was surprised. I could smell the resin
20 yards from the workshop. Death wish.

Keep asking Nathalie that is what Orchid is for. I hope we have
helped you.

Richard