Buying a prop-ox torch setup

On Thu, 26 Apr 2007 02:00:49 +0000, Abrasha wrote:

I have asked you many times to stop dispensing "knowledge" of things you
know nothing or little of. Once again, please stop.

And, finally, why don't you show us a picture of a piece where you have
attached high caret gold balls to sterling silver with heat. If you can't
show us that, then I am entitled to doubt you have ever done it, and I
clearly know more about it than you do.

On Wed, 25 Apr 2007 23:10:59 -0700, in rec.crafts.jewelry mbstevens
wrote:

On Thu, 26 Apr 2007 02:00:49 +0000, Abrasha wrote:

I have asked you many times to stop dispensing "knowledge" of things you
know nothing or little of. Once again, please stop.

And, finally, why don't you show us a picture of a piece where you have
attached high caret gold balls to sterling silver with heat. If you can't
show us that, then I am entitled to doubt you have ever done it, and I
clearly know more about it than you do.

Yeah, he started it. But stop bickering, please.

Besides, you were discussing what you thought happened, and choosing words which
might be argued as being imprecise, but which I'd suggest isn't a big issue. .
He, on the other hand, was disputing your use of certain words. One of you
discusses process, the other argues semantics. Now you propose to argue
whether he knows anything about the metalurgy, or is it semantics, based on
whether he's got photos? (which would depend not on knowledge, but on
photographic record keeping.) Remember, at the least, that he does have formal
credentials in his jewelry/metals training, which might, to some, count for
something in terms of whether he can be assumed to know what he's talking
about...)

And I'd point out tht he doesn't need to have affixed granules. Any affixing of
gold to silver by heating without additional solder would be the same type of
joint.

But as you guys seem to have done many times before, now you're managing to draw
ME into your argument too.
( Oh crap. I didn't want that to happen.)

I think we've all seen this movie before, gentlemen.

I wouldn't mind these debates of yours if you guys would at least disagree about
the same topic and debate that topic, and come to some useful conclusion, rather
than each of you going on about your own, sometimes apparently unaware that your
opponant is arguing a closely related, but not the same, subject. As often as
not, both of you are correct in your own areas. Here, I'd guess that MBS is
correct in what happens when the grains fuse, but has chosen the wrong term,
which even if true, doesn't affect the validity of the metalurgical premise. .
Abrasha, then pounces on the possibly incorrect useage of the term, and implies
that the underlying knowledge of the process is lacking, which equally doesn't
follow.
..
Sheesh, guys. Lighten up.

You, especially, please, Abrasha. You started this.

Peter.

On Thu, 26 Apr 2007 05:44:03 +0000, C0nnie wrote:

I will try granulation with 22 K gold on Argentium or fine silver
sheet some day soon.

I would be interested in knowing how this comes out. I have not bought
any argentium to experiment with yet.

On Thu, 26 Apr 2007 06:08:24 +0000, Peter W.. Rowe, wrote:

It's the same type of bond
produced by brazing, of course, but that's not really a valid label for it,
since no external bonding alloy is formed, if the gold does not melt.

I'm not sure I follow your point on this. When you braze steel, the steel
does not melt.

The bronze does move into any porosity in the steel (I
have seen photomicrographs of this), but the main bond is still metallic,
not mechanical, according to all sources I've come across.

So then,
perhaps neither welding, nor brazing, is accurate. Rather, then fusing would be
most accurate.

However, I'd guess that when the silver melts, the gold surface in contact with
it at least slightly melts too, forming a thin layer of eutectic alloy.

I don't know about that. The metal used on that ring seemed to have a
very much, much higher melting point than sterling. If you're interested
in specifics, I seem to remember the granules were from a Krugerrand. At
any rate, none of the granules have fallen off after much hard use.

In jewelry use, brazing is a term seldom used.

Yes. It should be, but is not. I like to use brazing because it can
never be confused with soft soldering.

The term "fusing" is not
especially specific. It does not require both surfaces to be the same, or both
to actually melt. All it requires is that two surfaces or items melt together
to form a bond. One can melt, or both can melt, so long as they join in the
process.

I've heard that applied to the adhesion of enamel to metal, and agree
that it must be a good general term. However, in the case of this ring, I
still think 'brazing' is a bit more specific and accurate, if nothing else
because it is metal to metal and very probably a metallic bond.

On Thu, 26 Apr 2007 06:08:24 +0000, Peter W.. Rowe, wrote:

However, I'd guess that when the silver melts, the gold surface in contact with
it at least slightly melts too, forming a thin layer of eutectic alloy.

This is at least possible, since the Krugerrand is alloyed with copper.
However, the granules had no treatment save a light coat of Handy flux,
and I rather doubt it.

On Thu, 26 Apr 2007 00:31:33 -0700, in rec.crafts.jewelry mbstevens
wrote:

On Thu, 26 Apr 2007 06:08:24 +0000, Peter W.. Rowe, wrote:

However, I'd guess that when the silver melts, the gold surface in contact with
it at least slightly melts too, forming a thin layer of eutectic alloy.

This is at least possible, since the Krugerrand is alloyed with copper.
However, the granules had no treatment save a light coat of Handy flux,
and I rather doubt it.

The copper doesn't play a major part in this, I don't think. In the usual
methods of granulation, the copper forms a lower melting alloy when it mixes
with the silver or gold with which it is in contact. But don't make the mistake
of thinking copper is the only metal this can happen with. Because silver,
mixed with gold (the two are completely soluable in each other), melts at a
lower temperature than do either of the two alone, a contact between silver and
gold will, if there IS a lower melting combination of the two metals in contact,
also mix with each other at the contact point, and can do it below the melting
points of either metal. Silver mixed with gold does not lower the melting point
as drastically and quickly as does copper with either one, but it DOES lower the
melting point of high karat gold. If the gold had lots of copper, then adding
silver might, with some gold/copper alloys, raise the melting point of any
resulting mix, so then this would not happen. But because there IS a mix of
your high karat gold with silver, that melts below that of the gold alone, then
a eutectic alloy will form when a small amount of the gold dissolves into the
silver, alowing both to melt together. What I'm usure of is whether this
potential alloy also melts significantly lower than the silver itself. I
suspect not, which is why you end up with the silver almost melting before you
get bonding, but then when it happens, I'll bet you find the gold grains seem to
sink rather easily into the silver. The above mechanism would explain that.

This is similar to what happens if you place a piece of brass, with flux, on a
piece of silver and heat them. Because brass alloyed with silver forms a lower
melting alloy (silver solder, to be exact, any of several grades depending on
proportions), at the melting temperature of the lowest melting of the
combinations of silver with brass (the eutectic temp of that system), the two
still solid and unmelted surfaces, of brass and silver, will combine without
first melting. They do that because the contact area itself, rather than one
surface or the other, allows that eutectic alloy to form, melting the interface.
This proceeds, of course, dissolving more and more of both surfaces into the
mix, forming more of the eutectic mix. With silver and brass, the potential
drop in melting point, ie the difference in temp between the melting point of
the eutectic mix and that of the two parent metals is rather large, leading to a
rather rapid combination when an unsuspecting jeweler heats the two together,
perhaps trying to solder them together. The brass can quickly sink right into
the silver as it does this, combining the two sometimes disastrously. I
suspect, but don't have data in front of me, that the reduction in melting point
that occurs at the contact between gold and silver is slight, making it a
controllable situation.

Again, in this case, you don't need to treat the granules, because the existing
dissimilarity between the metal of the grains, and that of the silver, already
provides the needed conditions for the bonding to take place.

That is, of course, all dependent on whether the addition of silver to your
kruggerand alloy raises or lowers the melting temp. Because there is already
copper in the gold, it's melting point may already be lower than what is
achieved by adding silver. If that is the case, AND if adding gold to the
silver does not then lower the melting point of the silver, then what would be
happening, as i said before, is simply that the silver is melting first and
fusing to the gold, without any formation of a eutectic. If this is the case,
then even so there will be some diffusion of the gold into the silver and silver
into the gold, which is why the bond then has strength beyond just "wetting".

Peter

On Thu, 26 Apr 2007 00:31:26 -0700, in rec.crafts.jewelry mbstevens
wrote:

On Thu, 26 Apr 2007 06:08:24 +0000, Peter W.. Rowe, wrote:

It's the same type of bond
produced by brazing, of course, but that's not really a valid label for it,
since no external bonding alloy is formed, if the gold does not melt.

I'm not sure I follow your point on this. When you braze steel, the steel
does not melt.


No, but with brazing steel, you've introduced a third brazing alloy. That's the
point. The bond takes place because a third alloy melts, flowing by capillary
action between the two still solid surfaces, both wetting them, and also bonding
to them. That's what happens with brazing. If, in your gold/silver
granulation, a third alloy is formed at the interface, distinct from either the
gold or the silver, then in metallurgical terms, a certain similarily exists.
But even in that case, the third alloy is formed by the interaction of the two
metals in contact with each other, which is NOT what the term brazing usually
describes, even if the end bond has similarities.


The bronze does move into any porosity in the steel (I
have seen photomicrographs of this), but the main bond is still metallic,
not mechanical, according to all sources I've come across.

Well, both. The penetration of porosity forms a mechanical bond, to be true.
But diffusion of the copper alloy into the steel, even if only slight, as well
as atomic bonds forming between atoms of iron and copper, etc, mean there is
also that metallic bond as well. The degree to which atomic bonding (metallic
bonding) occurs depends a lot on the difference in melting points. Because the
iron melts a LOT higher than does the brazing alloy, the diffusion depth, and
degree of metallic bonding that can take place, is limited to a very narrow
interface zone, and the difference in strength between a metallic bonded surface
and one that is just mechanical, or based just one wetting of the the one
surface with the other (like a glue), is probably not that much. You can
illustrate this difference by soldering/brazing a wire onto a piece of metal
with varying solders. With the lowest melting brazing or soldering alloys, it's
sometimes possible to just peel the wire away, like opening a sardine can,
breaking the bonds, but not the wire. Platinum soldered to gold or even more,
using gold solder, is a good illustration of this, as is platinum soldered to
itself just using the lowest grades of platinum solder. With a joint like this,
there may be some diffusion taking place at the joint interface, but it's so
slight in depth that for all intents and purposes, it doesn't do much more than
wetting the surface the same as a glue would do. Soft solder (lead solders,
etc), also fall into this catagory. Although they are metals too, and potential
alloys exist between the bonded surfaces and the metals in the soft solder, the
differences in melting point are so great as to confine the bond to a narrow
contact zone, thus limiting it's strength.
..

So then,
perhaps neither welding, nor brazing, is accurate. Rather, then fusing would be
most accurate.

However, I'd guess that when the silver melts, the gold surface in contact with
it at least slightly melts too, forming a thin layer of eutectic alloy.

I don't know about that. The metal used on that ring seemed to have a
very much, much higher melting point than sterling. If you're interested
in specifics, I seem to remember the granules were from a Krugerrand. At
any rate, none of the granules have fallen off after much hard use.

I'd expect that. Among other things, silver and gold are totally soluable in
each other. So diffusion zones can form that do not have lots of stress in
them. With copper, because it's much less soluable in either gold or silver at
room temp, diffusion zones/bonds can tend to be hard and sometimes prone to
cracking from the stresses that can build up as a result. That wouldn't be
happening here, so your bonding would likely be quite strong.



In jewelry use, brazing is a term seldom used.

Yes. It should be, but is not. I like to use brazing because it can
never be confused with soft soldering.

It's been said that each profession develops it's own vocabulary to talk to
itself, in part because it must, but also in part to build exclusivity between
it, and outsiders. Nobody ever said it had to make sense, and the English
language is rife with examples of words used in one context differently from in
other contexts, with no apparent logic other than convention. In this case,
while it's technically correct to use the word brazing to describe jewelry hard
soldering, you're setting yourself in a rather small minority, apart from the
conventional usage. In our field, soft soldering is distinguished by using
extra terms, ie "soft", or "lead", rather than the word "soldering" itself.
Again, no real logic, but on the other hand, jewelers themselves don't seem
confused on the issue... For one thing, there's often the issue of non-verbal
communication aiding things, since when talking about soft, or lead, solders,
most jewelers also communicate a sense of disgust, regret, or disdain for the
inferior method and material, again removing doubt as to what's being
discussed...

(grin)



The term "fusing" is not
especially specific. It does not require both surfaces to be the same, or both
to actually melt. All it requires is that two surfaces or items melt together
to form a bond. One can melt, or both can melt, so long as they join in the
process.

I've heard that applied to the adhesion of enamel to metal, and agree
that it must be a good general term. However, in the case of this ring, I
still think 'brazing' is a bit more specific and accurate, if nothing else
because it is metal to metal and very probably a metallic bond.

Mike, welding is also metal to metal, and so is soft soldering, and so is
brazing, etc etc. And in all cases, even including lead solder, there is also
that metallic bond. That's not a useful distinction. All these bonds are at
least in part, a metallic bond. The useful distinction is the source of the
alloy that has flowed between the surfaces to be bonded. Does it come from the
parent metals themselves, either just one surface melting onto the other or both
surfaces combining and melting together? Or does it come from a seperate,
externally applied alloy? THAT's the distinction being made. The end result
bond type is "metallic", essentially the same in all these instances even if
specific details of bond layer or composition, etc differ. . Brazing, as with
jewelers hard soldering, implies the ADDITION/introduction of solder/brazing
alloy in some form to the joint, rather than the formation of a bond from
existing metal. Welding or fusing do not require that addition, (though welding
often needs it for a good weld geometry). You're fusing the grains on, not
soldering or brazing them.

Peter

On Thu, 26 Apr 2007 08:16:10 +0000, Peter W.. Rowe, wrote:

You were right in another post that all this arguing about terms is of
much less importance than trying to understand exactly what was going on
when the gold was attached to the silver. None of the terms are so
perfectly clear that all speakers of English or jewelers will agree on the
use of all of them. However, this seems to be entertaining both of us, so
I shall try to forge ahead for a while to try to clearify the concepts.


In this case,
while it's technically correct to use the word brazing to describe jewelry hard
soldering, you're setting yourself in a rather small minority, apart from the
conventional usage.

I don't really think so. Most jewelers here understand that hard
soldering is really a form of brazing, and are willing to accept either
term. I would accept silver brazing or silver soldering for the way the
granules are attached on this particular ring. It might have been
more politic of me to have used "silver brazing" instead
of "brazing" to be more specific, but I think it is still correct and
easily understood.

The term "fusing" is not
especially specific. It does not require both surfaces to be the same, or both
to actually melt. All it requires is that two surfaces or items melt together
to form a bond. One can melt, or both can melt, so long as they join in the
process.

I've heard that applied to the adhesion of enamel to metal, and agree
that it must be a good general term. However, in the case of this ring, I
still think 'brazing' is a bit more specific and accurate, if nothing else
because it is metal to metal and very probably a metallic bond.

Mike, welding is also metal to metal, and so is soft soldering, and so is
brazing, etc etc. And in all cases, even including lead solder, there is also
that metallic bond. That's not a useful distinction.

Yes, but I was arguing just above that fusion can even apply to the bond
between glass and metal, where there is no metallic bond. Brazing cannot
be applied to things like enamel adhesion; this suggests that brazing
(hard soldering) may be closer in the family of concepts of what happened
when this ring was made. And, more traditional granulation is actually
fused.

All these bonds are at
least in part, a metallic bond. The useful distinction is the source of the
alloy that has flowed between the surfaces to be bonded. Does it come from the
parent metals themselves, either just one surface melting onto the other or both
surfaces combining and melting together? Or does it come from a seperate,
externally applied alloy? THAT's the distinction being made.

I don't think that is how it is applied, because brazing can be applied
for things like coating of a parent metal to protect it from corrosion,
etc. The thing that distinguishes brazing, or hard soldering, from
welding and soft soldering is that it occurs above a certain temperature
(to distinguish it from soft soldering), and that one metal is flowed onto
the other which does not melt, and forms a bond.

The end result
bond type is "metallic", essentially the same in all these instances even if
specific details of bond layer or composition, etc differ. . Brazing, as with
jewelers hard soldering, implies the ADDITION/introduction of solder/brazing
alloy in some form to the joint, rather than the formation of a bond from
existing metal.

Well, that is what I have been arguing against. I have another
counter-example. Solder inlay using silver solder. Here, only the solder
is joined to the non-melting metal. I don't see how we are to deny that
the application of this is silver brazing or hard silver soldering, or
just plain brazing.

On Thu, 26 Apr 2007 08:16:10 +0000, Peter W.. Rowe, wrote:
Brazing, as with
jewelers hard soldering, implies the ADDITION/introduction of solder/brazing
alloy in some form to the joint, rather than the formation of a bond from
existing metal.

It occurs to me that I may have misunderstood your argument in my reply
to the above statement.

Under everyday conditions it *happens* to be true that a flowing alloy
is introduced to a joint. But the usage of "hard soldering" or "brazing"
does not *require* this. It seems to me that the physical
attributes of the join itself are more important. If those physical join
attributes are closer to that of an everyday brazed joint than to, for
instance, the attachment of enamel to metal then it would be better to
use "braze" than "fuse."

On Thu, 26 Apr 2007 08:12:47 -0700, in rec.crafts.jewelry mbstevens
wrote:


I was arguing just above that fusion can even apply to the bond
between glass and metal, where there is no metallic bond. Brazing cannot
be applied to things like enamel adhesion; this suggests that brazing
(hard soldering) may be closer in the family of concepts of what happened
when this ring was made. And, more traditional granulation is actually
fused.

As I said, the term fusing is fairly imprecise, and refers to multiple types of
operations. All it really implies is a melting together. To suggest,
however, that fusing two pieces of metal together is the same thing as fusing
enamel to metal just because the same term may be used, is incorrect. The two
operations produce a different type of bond, as you seem to also suggest. The
fact that melting enamel onto metal can be called fusing does not somehow give
the word brazing, a greater breadth of meaning.

Here's the main key concept. In brazing, or traditional hard soldering, what
melts is a distincly different alloy, one who's different composition gives it a
lower melting point than the metals being joined. The generally high
temperatures involved mean the difference between these melting points may not
be all that much, and brazed or soldered joints made with a lesser difference in
melting point between filler alloy (solder, etc) and the bonded surfaces, will
enjoy a greater degree of diffusion of the filler alloy into the bonded metals,
and thus a stronger joint, and a better looking one. But this is still
soldering or brazing, not fusing, because it's taking place via the melting of
this distinctly different alloy. In fusing, the parts being bonded are
themselves simply melted together, or one melted onto the other.

In classic soldering or brazing operations, the filler metal is added as a
seperate piece of metal, or placed on or in the joint, where it melts bonding
the pieces together. it can also be "added" by being generated in situ, which
is what happens with the classic methods of granulation, where the distincly
seperate and lower melting bonding metal is alloyed in place when the plated-on
copper mixes with the gold or silver at the surface of the grains, allowing
that surface layer to melt at a temperature below that at which the body of the
grains or substrate itself would melt.

Granulation can also sometimes be done without this added material, so there is
not a seperate alloy formed at the joint. In this case, generally bonding takes
place because the metal, such as sterling silver, does not melt into a puddle at
one single temperature. Sterling silver is a mix of two types of crystal
compositions. One is a eutectic alloy of copper and silver that melts at that
combinations eutectic temperature. The majority is mostly silver with just a
small amount of copper that melts considerably higher. When you melt sterling
silver, as you reach the eutectic temperature, those copper rich grains start to
melt, allowing the metal to look "wet", and starting to melt, while the main
bulk of the metal, and it's shape, are maintained by the larger mass of higher
melting silver rich crystals. Only as you raise the temperature, allowing the
eutectic alloy to dissolve more and more of the silver rich phase, does the
whole mass melt. When you granulate with sterling silver as either the base
metal or the grains (the first is more common), yet without added copper, then
what you're relying on is that as the silver first starts to melt, it's surface
becomes "wet", allowing bonding to take place. However, this is not due to a
distincly different alloy formed at the surface. That is simply how the whole
mass of metal is acting, and it's structure returns to it's prior state upon
silidification. The bonding you see with your gold grains onto sterling silver
may look like just the surface is starting to flow, but this isn't correct. What
is happening is that a small PERCENTAGE of the silver is melting, both on the
surface and through it's bulk. You only see it at the surface, however.
If you doubt that this is the case, heat sterling to that temperature where it
starts to look "wet", and press something into it. It will yield easily, like a
mass of wet sand, because the copper rich crystals having melted, the rest of
the structure is only barely holding together. It's not just the surface. The
whole mass becomes slightly slushy.

Because the bonding is taking place simply because of the way the silver itself
melts, allowing the higher melting gold to bond without it's losing integrity,
but doing so without the introduction or formation of any different and lower
melting alloy, I still say you're fusing your grains on.

If you'd copper plated the gold or silver, or otherwise treated or changed the
surfaces of the metals, to force the formation of a specific eutectic alloy
which would then do the bonding for you, then you'd be correct in calling this
soldering or brazing.

I'll admit the difference is subtle in some cases, and linguistically confusing
in others.

But you also state that what should distinguish the difference is the nature of
the bond. Here, you're on thin ice, since unless you're talking about bonding
very dissimilar materials like metal and enamel, there is not that big a
difference in the nature of the bond. Two pieces of sterling silver bonded by
just fusing them together, versus the same two bonded with a tiny bit of hard
solder, do not have a clear difference in the nature of the bond. If, in
soldering, a minimum amount of solder was used with a good fitting joint, and if
the soldering heat was maintained for a little bit, then the different
componants of the solder will have diffused into the silver enough so that
subsequent remelting of the solder might be difficult or impossible, so then in
essence, the joint is the same as a fused one. And in fact, metalurgical
analysis of ancient gold and silver work often fails to find any trace of solder
or higher percentages of copper, etc, at joints. The reason is not that it
wasn't used, but that it's dissipated over time into the parent metals. With
good heat contol, the same thing can be done in shorter time too.

Peter