Jay,
I guess we just see color a little differently. Perhaps your studio
produced alloy has a white appearance. The PW’s that I’ve worked
with would definitely be in the white family but to my eyes are not
really white at all. They are very beautiful though.
I still wonder about the durability long term. Bezels seem to wear
faster in PW…
In my experience.
Take care,
Andy
As someone who works day in day out manufacturing gold and silver
alloys this whole to forge or not to forge discussion is really
interesting. On many occasions i’ve had to pour up to 1/2 kg of 9ct
y/g into a steel sheet mold and then roll it all the way down to
0.3mm sheet. Not once have i ever forged the ingot prior to rolling
and to be honest I can’t think of a single time when something hasn’t
worked an i’ve thought “maybe i should have forged that first”.
Personally I have more dramas with porosity and bubbles (especially
in lower carat golds when pouring sheet) than I have with grain
structure issues and I would probably do at least 10 -15 pours a day
in to a steel mold ranging from 5gm-500gm. The key thing i’ve found
is to pour the metal at the right temp into a mold at the right
temperature which to be honest is something that you get the knack of
after a while and something that is near impossible to describe.
Nowadays I can pretty much tell by how the metal flows out of the
crucible into the mold whether it has been a successful pour or not.
As for annealing I generally use a kiln which makes it a lot easier
to hold the temp for whatever length of time necessary which can make
a big difference with some alloys, possibly not the most practical
way of doing things in a smaller studio but when you are dealing with
anything over 200gm it really is the only way to anneal evenly.
Luckily for me the other option i have is a reduced atmosphere
furnace which is used for 5kg+ coils of sterling and sheets up to
1.5mt long. As someone who makes objects this is great for avoiding
firescale issues.
Ben
I guess we just see color a little differently. Perhaps your studio produced alloy has a white appearance. The PW's that I've worked with would definitely be in the white family but to my eyes are not really white at all. They are very beautiful though.
I have not made 18kt palladium alloy, I have cast a 14kt palladium
ring. It was a wedding band for one of my employees. She wore it for
a short while, and was unhappy with the color, it to darkened to a
gray white. I thought I did something wrong, and made it again. Same
issue. She ended up being happy with traditional 14kt white. It was a
long time ago and people were not making such an issue about white
gold alloys. This was before I started using David Fell"s winter
white, which I have made hundreds of rings with. There has not been
one issue about allergies to nickle white gold. Maybe I just have
good karma:)
Richard Hart G.G.
Denver Co.
Not once have i ever forged the ingot prior to rolling and to be honest I can't think of a single time when something hasn't worked an i've thought "maybe i should have forged that first".
I and a friend (who is smart) read all the offlist links and.pdf’s
about grain structure and concluded that hammering on the metal
won’t make the grains any smaller. Forging at best bends and distorts
the crystalline grains/structures but doesn’t make them any smaller.
I’m going to continue to not forge ingots for the next 30 years.
Paf
As someone who works day in day out manufacturing gold and silver alloys this whole to forge or not to forge discussion is really interesting. On many occasions i've had to pour up to 1/2 kg of 9ct y/g into a steel sheet mold and then roll it all the way down to 0.3mm sheet. Not once have i ever forged the ingot prior to rolling and to be honest I can't think of a single time when something hasn't worked an i've thought "maybe i should have forged that first".
Well since you have never tried it how do you know? Do you routinely
do micrographs of your alloys to assess crystal structure, tensile
testing for UTS, hardness tests or Erichsen Cupping tests to look at
ductility? If you were to do these tests you would be able to
clearly see the difference in a forged and annealed billet vs a
directly rolled ingot. If you work in a current day manufacturing
company time is money, so making it better is not typically the goal
so much as making it acceptable quickly and getting it out the door.
Most buyers/users never push the metal hard enough to see the real
advantages of better grain structure so most manufacturers don’t
bother. There is a fair amount of good science behind the reason one
would want to forge then anneal before rolling for the highest
quality metal. In a small studio situation where melting and
annealing temperatures are done by eye, volumes are tiny and there
aren’t controlled atmosphere furnaces for annealing and other tools
that are common in a manufacturing facility forging can help make
the difference between a cracked billet and a good one. So while I
am certain the practice you describe is the common one for current
manufacturing practice in ingot cast precious metals that does not
mean it is going to produce the highest quality metal, continuous
cast metals have their own issues that could also be improved by
forging. When I am deep drawing heavy section tube I buy the closest
thing I can get to the raw continuous cast ingot so that I can forge
it and anneal before final rolling to thickness. If I do not do this
I am very likely to end up with cracking and surface defects from
the crystal structure of rolled only sheet. So I know that forging
improves the crystal structure of the sheet.
James Binnion
James Binnion Metal Arts
Hi James,
I’m getting a copy of Brephol’s book as recommended by yourself, so
I’m,k hoping it will shed a bit more light on the subject.
I will try the forge before I roll, and I will compare it to an
ingot that is just rolled.
However I am tempted to use a drop hammer or a power hammer for
obvious reasons.
Will let you know how I go.
Regards Charles A.
Hey Andy!
I always tell my students that their finished pieces will look better
longer if they keep them in a jewelry box at home and don’t wear
them…
Jay
Forging at best bends and distorts the crystalline grains/structures but doesn't make them any smaller.
Paf, the same can be said of rolling. Working the metal by rolling
or forging only distorts the crystals, as you note. It never makes
them smaller. What makes them smaller is when you anneal worked
metal, the distorted crystals break up into several new, smaller
crystals. The difference between forged and rolled metal is in the
structure formed by the distorted crystals. With forged metal, the
distortion/working of the crystals in in all directions, no linear,
and forging tends to work the metal through it’s entire thickness
more evenly, rather than working the surface differently or more than
the center of the ingot. So with forging, the distorted and bent and
stretched crystals in the metal form more of a uniform structure even
before it’s annealed, and after annealing, the resulting
recrystalized metal is also more uniform. With rolling, the crystals
are distorted in a linear direction, giving it more “grain”, and the
surface layers tend to be distorted more than the center. So after
annealing, some of this directional grain remains, and because the
surface was worked more than the center, the surface of the annealed
ingot will have smaller crystals than the center does. The forged
ingot thus gives you a more uniform structure throughout the metal.
Whether this makes an actual difference to you depends on what you’re
doing, as well as what the alloy is. Some alloys are already so
forgiving it’s hard to push them past their limits. With others, it
makes a big difference.
But for the record, I too seldom forge my ingots. I’m usually not
demanding so much from my metal that it needs it. But the difference
is there.
Peter
This stuff about forging and annealing ingots is really metallurgy
101 stuff. Get the books and read up on it. Or if you feel that
because you have done something for the past x number of years and
you don’t need to learn how to do it better then please continue to
do what you have been doing. It will not change the fact that you
will get better quality metal if you properly forge and then anneal
the metal before rolling.
James Binnion
James Binnion Metal Arts
I and a friend (who is smart) read all the offlist links and.pdf's about grain structure and concluded that hammering on the metal won't make the grains any smaller. Forging at best bends and distorts the crystalline grains/structures but doesn't make them any smaller.
Either you or your friend missed the anneal bit of the process.
Forging distorts the grains and puts them under a significant amount
of strain when forging is followed by annealing the crystal matrix
relaxes and recrystalized in a smaller uni-axed grain structure. You
must do both to gain the advantage of the process.
James Binnion
James Binnion Metal Arts
I’ve been off for a while enjoying quality time with my family. Sorry
for this late reply!
"Well I could stop experimenting, but I'm willing to do it and what's the harm?"
Charles, don’t understand me wrong here. Do as you please and keep
doing it as long as you want.
I know by fact that many newbies and others are trying to mixe some
metals together and find out by experience (or not) what works hoping
to make their own alloy cheaper.
Qiuet honnest, I’ve been there too! Many years ago someone thold me
that white gold was made by adding nickel to the alloy as a
“bleaching” agent. Another person thold me that a american nickel (5
cent) was pure nickel and off I went… yep, disaster after
disaster, imagine!
After many trials and error I started reading books and investigated
about alloy making.
I’m repeating myself by saying that one needs more then a melting
pot, killn and etc. Soffisticated equipment is needed badly!
More then this, one needs knowledge of crystal structure, ordering
and disordering of atoms (as Jim already mentioned in an other
article), ternary and phase diagrams, transition of metal, alloy
standards and much much more.
If you’re into this subject you know properly more then I do about
this subject.
If you know what you’re doing then have fun and I wish you all the
luck, I’m serious. For all th other ones, think twice, this is
metalurgy at high level.
Unfortunately when you're using non-traditional elements in experimental jewellery alloys, you're pretty much on your own.
Yep, you are indeed!
Phase diagrams are not calculated, they exist through experiments, measurements, and observation.
Yes and again, if you kown what you’re doing using a controlled
environment and precise measurements or/and help from an institution
and enough finances.
Is it a waste of time and resources(?)... maybe... but then again I may find something useful.
I hope that small phrase powers you with enough energy to keep-on
going Wishing you the very best in your study and practice in finding
something useful
Enjoy and have fun
Pedro
I've been off for a while enjoying quality time with my family. Sorry for this late reply!
Good to hear 
I hope that small phrase powers you with enough energy to keep-on going Wishing you the very best in your study and practice in finding something useful
Thank you Sir, the search is what drives me on 
Kindest regards Charles A.
Hello Jim,
I have followed this thread with interest and would like to suggest
that maybe the forging of ingots and the effect of the surface
crystal structure on re-crystallisation is metallurgy 201? But
seriously, particularly for small scale, chill cast ingots the
forging techniques demonstrated by Leonid where he works the surface
at 45 degrees to the direction of casting will have a beneficial
effect on the subsequent re-crystallisation of the surface grains
when they are annealed. For those that want a more technical
explanation, in addition to the two books recommended by Jim, 'The
Plastic Deformation of Metals by R W K Honeycombe gives more detailed
about grain structures and the effects of annealing and
different working processes.
Where silver alloy sheet is produced commercially by continuous
casting, the ‘surface skin’, which the forging process that has been
discussed effects, should be removed by a scalping or a milling
operation prior to rolling commencing to ensure good surface quality
in the finished sheet. In addition, the commercial rolling mills
used for sheet production allow the centre of the cast strip to be
worked due to the significantly higher roll pressures that can be
applied compared to those available using ‘silversmiths’ rolling
machines. In all of this discussion I would highlight two points that
have made to help with quality sheet production; get a significant
reduction into the cast bar/strip (at least 50% reduction in
thickness) before annealing and also get the annealing correct. It is
important to heat the metal for long enough to get proper
re-crystallisation of the grains occurring, not just a drop in
hardness.
Charles Allenden
Mr. Binnion–I was somewhat misquoted as to what I related to my
friend about the forging question. Indeed, forging will produce
smaller crystals more equitably distributed in the mass of metal. A
good thing. What I maintained is that when an ingot is cast in
preparation for milling, then annealed and put through several passes
in the mill, annealed again, rolled, etc. the results would bed
similar. This is what we do and have not seen the failures mentioned
by those who advocate forging before rolling. My understanding is
that the function of annealing is to change the crystalline structure
so that stress leads to “slippage” between crystals without
stress-linked fractures. I admit that my academic and practical
experience is more applicable to steel and its alloys. I think the
principles are largely the same. In steel (0.25% carbon) heating
above 1350 F. ferrite recrystallizes from alpha to gamma form
(austenite). Upon cooling the final grain size of pearlite and
ferrite depends greatly upon the fates of heating and cooling.
( I know that there are other crystal forms such as the hard
martensite and cementite, but lets leave it here). Cool too fast and
the steel is too hard to work easily with a hammer. Held at the
right temperature and cooled at the right speed, annealing occurs.
My understanding of how silver (which I prefer to use in most cases
for jewelry) and gold respond to annealing is that annealing will
mitigate fractures when the metal is worked mechanically up to the
point where it is work hardened and will break when deformed.
So, what I said to my friend was that forging would alter
crystalline structure. It is counterintuitive to me that a forged
piece of sillver or gold will behave better when rolled than ones
that have simply been annealed to survive the mechanical stress of
milling which would seem to be similar to forging. I did not think
that the forging was necessary unless it solved some problem (which
we are not having).
The second problem I found in the discussion was the fact that there
seemed to be no quantification in the statements. The forged piece
will last longer—years, decades, centuries??? How much longer (I
suspect that this cannot be answered and wont expect an answer but
would be delighted to get one.) Further, at one point we are told
that “a lot of small taps is much better than fewer hard taps”. I do
not automatically understand the value of “a lot”, “small taps”,
etc. I suppose watching you doing the job would help, but I suspect
that the force of a hammer blow is strongly affected by ones arm and
the hammer handle length and weight of the head.
The metal hammered pre-milling is denser. This is likely to be
true–at first. Is this true after the metal is worked by milling?
Is this one of the endless and mainly illogical discussions such as
whether a cast piece can be hand made? Honestly, I don’t know and
haven’t found the to help me decide.
It is obvious that I am not a metallurgist, but this stuff is neither
rocket science not politics. There should be a reasonable answer
The second problem I found in the discussion was the fact that there seemed to be no quantification in the statements.
I am going to throw out another option, why don’t all the people who
say you don’t have to forge first, prove it. Why is it always up to
in this case the traditional way to prove a statement. I want to see
test and analysis that proves the traditional way wrong. When ask to
show us what someone can do all we get is excuses. I offered to
supply the diamonds and gold for someone to make the Leonid’s
eternity bad from CAD and had no takers. It’s time the naysayers step
up to the plate so we can see if they can bat.
Bill Wismar
On melting gold. I can’t remember where I found this formula. If you
add 1% titanium to pure gold you get a virtually indestructible
casting that assays 99% gold. Does this work? Is this what is sold in
Asia as pure gold?
My bullion dealer says it can be done, but the finished piece cannot
be resized or soldered.
TTFN
Richard
What I maintained is that when an ingot is cast in preparation for milling, then annealed and put through several passes in the mill, annealed again, rolled, etc. the results would bed similar.
There are two glaring mistakes in the above. Annealing ingot right
after casting, without inducing cold working stress ( theory
requires 70% change in dimension, but in practice one has to be
content with lesser values ), will only make matters worse. Annealing
should not be taken lightly.
This is what we do and have not seen the failures mentioned by those who advocate forging before rolling.
That depends on how one defines failure. Different alloys behave
differently. Some do crack and some can survive milling stage. But
even those who make it, still have inferior structure compared to the
forged ones.
I admit that my academic and practical experience is more applicable to steel and its alloys. I think the principles are largely the same. In steel (0.25% carbon) heating above 1350 F. ferrite recrystallizes from alpha to gamma form (austenite). Upon cooling the final grain size of pearlite and ferrite depends greatly upon the fates of heating and cooling.
I take it that above was written in a hurry, because nonsensical
nature is self evident. I am sure that author would like to withdraw
it upon careful re-reading.
It is counterintuitive to me that a forged piece of sillver or gold will behave better when rolled than ones that have simply been annealed to survive the mechanical stress of milling which would seem to be similar to forging.
“would seem” has different meaning than affirmative “is the same”,
which is required here if one is sure of his position. And if one is
not, - than statement has no meaning.
The second problem I found in the discussion was the fact that there seemed to be no quantification in the statements. The forged piece will last longer---years, decades, centuries??? How much longer (I suspect that this cannot be answered and wont expect an answer but would be delighted to get one.)
To give general answer is enough to say that it depends on type and
design of jewellery. If it is a thick square with the hole drilled in
a corner to wear it as a pendent, than absolutely anything will be
satisfactory. But if it is a ring to be worn every day and the ring
incorporates delicate structures; a goldsmith simply must give it
the best chance of survival from daily abuse, by taking every
opportunity to strengthen it. Pre-forging is a very important tool in
goldsmith repertoire. Non pre-forged alloys are defective from the
point of view that they are not as good as they can be. Wether or not
it will show as a defect in finished product would depends on the
product and its application.
Leonid Surpin
I was somewhat misquoted as to what I related to my friend about the forging question. Indeed, forging will produce smaller crystals more equitably distributed in the mass of metal. A good thing.
I copied and pasted your post so I do not see how I misquoted you
and I do not see how it was out of context either. Ant neither one
was my intention.
What I maintained is that when an ingot is cast in preparation for milling, then annealed and put through several passes in the mill, annealed again, rolled, etc. the results would bed similar.
Any piece of metals microstructure is a determined by its chemistry
and its work history. The results between a forged, annealed and
then rolled billet and an ingot that has just been rolled to the
same amount of reduction will differ. With enough rolling and
annealing cycles they will become virtually indistinguishable but in
precious metals we don’t often make ingots large enough to
accomplish that much work. Certainly at the level of a studio smith
you might do two cycles of proper rolling and annealing to get to
final working thickness but not much more. So in that case it would
be still apparent what the difference was.
This is what we do and have not seen the failures mentioned by those who advocate forging before rolling. My understanding is that the function of annealing is to change the crystalline structure so that stress leads to "slippage" between crystals without stress-linked fractures.
What annealing does if there was an adequate amount (typically
greater than 50 % reduction in section) of cold work prior to
annealing is to return the crystal matrix to a relaxed state and if
there was enough cold work then there will be recrystallization
where the energy required to form new crystals is lower than the
energy for the crystal to morph back its equiaxed shape. This
recrystallization is what makes the smaller equiaxed crystal
lattice.
Slippage is along planer layers of atoms in the lattice of a crystal
creating slip planes. Grain or crystal boundaries are impediments to
slip as the orientation of planes in adjacent crystals is different
so the direction of slip will need to be different requiring more
energy. This is what makes poly crystalline materials stronger than
single crystals and why many small equiaxed crystals will be a
durable configuration than larger or more directional oriented
crystal lattices. If there is enough strain on a pair of adjoining
crystals they will not deform by internal slip but fracture, larger
or longer crystal boundaries allow the matrix to fracture more
easily as the longer boundaries more easily propagate the fracture.
Which brings us back to the ingot. look at this image of the crystal
structure of an as cast ingot
http://www.ganoksin.com/gnkurl/ep7zec
In a metal ingot mold as the molten metal is introduced the mold it
begins to immediately nucleate crystals on the mold wall due to the
metal molds high thermal conductivity and high thermal diffusivity.
This produces a layer of very fine tight equiaxed “chill” crystals
then as the thermal flux is reduced by this layer the faces of those
chill crystals pointing in a favorable direction into the melt begin
to grow into long columnar crystals oriented towards the center of
the molten volume. Ideally there will then be enough reduction in
heat transfer for the middle of the ingot to slow its cooling enough
for more equiaxed grains to begin to precipitate out of the melt
resulting in the structure shown in that URL.
Depending on the amount of super heat (heat in excess of the melting
temperature) in the metal and melt/ingot size those columnar grains
can continue all the way to the middle of the ingot this will create
what is known as a pipe and can lead to significant problems when
rolling as the impurities in the melt will mostly end up where the
advancing columnar grains meet from the opposing and adjacent sides
leading to a weakness in the crystal lattice. This is the common
structure fro the ingots that we cast as studio smiths because we
have tiny melt volumes and we are struggling to get enough heat into
the melt to keep it from freezing It looks more like this.
and this image of a silver ingot interior
The ingots will have a significant tendency to fail at the
intersections of the columnar grains from the faces of the mold. So
combining this with the long perpendicular grain boundaries of the
columnar grains and strain introduced by the shrinkage of
solidification you have a piece of metal that is not in optimal
condition for rolling. Will this structure automatically result in
failure, no it will not but it will increase the likelihood of
defects in rolling and further on down the line.
Bu subjecting the as cast ingot to heavy forging those structures
will be destroyed by the deformation and subsequent annealing to
produce a billet with an fine equiaxed grain structure that will
better stand up to further deformation in rolling and other forms of
plastic deformation in later processing stages.
I admit that my academic and practical experience is more applicable to steel and its alloys. I think the principles are largely the same. In steel (0.25% carbon) heating above 1350 F. ferrite recrystallizes from alpha to gamma form (austenite). Upon cooling the final grain size of pearlite and ferrite depends greatly upon the fates of heating and cooling.
( I know that there are other crystal forms such as the hard martensite and cementite, but lets leave it here). Cool too fast and the steel is too hard to work easily with a hammer. Held at the right temperature and cooled at the right speed, annealing occurs.
Steel is a much more complex animal due to its interstitial solid
solution crystal structure it forms many complex crystal states
depending on temperature and speed of heating and cooling. Most of
the alloys we are concerned with are substitution solid solutions
with much simpler behavior.
http://www.ganoksin.com/gnkurl/ep7zed
My understanding of how silver (which I prefer to use in most cases for jewelry) and gold respond to annealing is that annealing will mitigate fractures when the metal is worked mechanically up to the point where it is work hardened and will break when deformed.
If the lattice is actually stressed to the point of fracture
annealing will not fix it. With a fracture the only way to fix it if
it doesn’t actually come to the surface is hot forging or Hot
Isostatic Pressing then you may be able to get diffusion to fix the
crack.
So, what I said to my friend was that forging would alter crystalline structure. It is counterintuitive to me that a forged piece of sillver or gold will behave better when rolled than ones that have simply been annealed to survive the mechanical stress of milling which would seem to be similar to forging. I did not think that the forging was necessary unless it solved some problem (which we are not having).
Forging and rolling apply deformation to the metal in different ways
rolling presents a much higher stress to the metal. Forging delivers
more of its energy to the area below the struck surface because
friction keeps the material in direct contact with the hammer and
anvil from spreading sideways. So in effect it works the interior of
the metal more than the exterior surfaces as shown here
http://www.ganoksin.com/borisat/nenam/nenamart/brepohl-clipart/4-44.gif
In rolling the stress is distributed more like this
http://www.ganoksin.com/borisat/nenam/nenamart/brepohl-clipart/4-46.gif
Unless you have a very stout powered mill with large diameter rolls
the middle shaded area in that diagram is not affected by rolling
and you end up with a very unequal distribution of stresses across
the whole width and length of the rolled sheet. The this article
that these images came from is the section of Chapter 4 in Brephol
that covers much of what we have been discussing here and much to my
surprise I found it here on Ganoksin today while looking for images
to illustrate this post, thanks to Brynmorgen Press and Hanuman for
publishing it there.
The second problem I found in the discussion was the fact that there seemed to be no quantification in the statements. The forged piece will last longer---years, decades, centuries??? How much longer (I suspect that this cannot be answered and wont expect an answer but would be delighted to get one.)
I am in agreement with you here in that there is no data I know of
to quantify this.
Further, at one point we are told that "a lot of small taps is much better than fewer hard taps". I do not automatically understand the value of "a lot", "small taps", etc. I suppose watching you doing the job would help, but I suspect that the force of a hammer blow is strongly affected by ones arm and the hammer handle length and weight of the head.
As I did not make this assertion I cannot make any comment on it. I
tend to use power hammers and presses to forge my ingots.
The metal hammered pre-milling is denser. This is likely to be true--at first. Is this true after the metal is worked by milling? Is this one of the endless and mainly illogical discussions such as whether a cast piece can be hand made? Honestly, I don't know and haven't found the to help me decide.
The metal cannot be made denser in any practical sense by forging or
rolling. Density is a physical property of the metal that short of
terribly extreme forces (think nuclear explosion or black holes) we
cannot change. I cannot imagine an ingot could contain enough gas
porosity to significantly effect its density and if it did it would
likely exhibit severe defects during processing that would make the
density issue moot. SO no forging or rolling is not going to change
density.
It is obvious that I am not a metallurgist, but this stuff is neither rocket science not politics. There should be a reasonable answer
I hope some of what I have written here will help provide some
answers. I have not written more lately due to shattering and
subsequent surgery on my right index finger which has made typing
most cumbersome. It is finally getting to the point where I am able
to type longer posts.
Regards,
Jim
James Binnion
James Binnion Metal Arts
Hello,
On melting gold. I can't remember where I found this formula. If you add 1% titanium to pure gold you get a virtually indestructible casting that assays 99% gold. Does this work? Is this what is sold in Asia as pure gold?
It can be don but not under normal conditions. An inert atmosphere
is needed to make the alloy. Due to the little percentage of Titanium,
this alloy may be sold as pure gold when 1% Ti is used.
My bullion dealer says it can be done, but the finished piece cannot be resized or soldered
Read this complete report to inform yourself about this product.
http://www.ganoksin.com/gnkurl/ep7zel [PDF file]
For those who are still having trouble about grainsizing, here is
(again) another prove. However, by all means feel free to continue
your way of working.
Have fun and enjoy
Pedro
Hi Bill,
Don’t take this the wrong way, but we all don’t know all of the
members on this list, apart from a net presence. You don’t know me, I
don’t know you.
Why is it up to the traditional way to prove a statement? Well,
Bill, it’s not just the traditionalists that have to prove what they
say.
Everyone on this list, when challenged, has to prove their point of
view, if they want to get their point across.
Saying “I’ve been doing X process for X amount of years, without
issue,… therefore it must be the best and only way to do it”,
isn’t credible these days.
If I said to you “Bell metal is brittle”, and described my
experiences with it, you may accept that, but if you challenged me
and wanted further verification, that “bell metal is brittle”, I
would have to provide further proof. Say contacting the guys that
made the Liberty bell, and get a third party expert opinion to back
up my experiences.
Offering to supply diamonds and gold is very generous of you, and if
you get a decent image of Leonid’s ring side elevation would do,
slightly tilted would be better, I’ll complete the model, and send it
to you. The channels were a doddle, the claws are difficult if you
can’t see the details of the ring. There will be no problem making
that eternity ring in CAD, it will look the same, it will accept
stones, it will even polish, but it will not be work hardened. I’ve
been completing the CAD section of my trade course and Rhino Gold
should take a lot of the work out of drafting the CAD.
Mind you I deal with very professional, and very competent casting
houses, that produce high quality castings. I’m sure there are
professional business there that are of equal (if not better)
quality.
Regards Charles A.
