[Peter Wieck]

On Dec 10, 6:45*pm, wrote:
On Dec 10, 6:07*am, wrote:





Greg Wormald wrote:

"My memory made we wonder about the previous post on the wearing of
LP's by styli because I noticed they were washing the test LP's fairly
frequently with an alcohol solution, and (probably) with inadequate
rest
between playings."

G. Alexandrovich, “Disk recording and playback”,chapter 25 in
“Handbook for sound engineers” by G. Ballou, 2nd edition 1991

“Because of the small contact area that exists between the stylus tip
and the groove, the pressure against the groove wall can rise up to
many thousands of psi. For instance, if each wall receives 0.7 gram of
force applied through the contact area equal to 2 ten millionth of an
inch, the pressure is 7726 psi. It has been experimentally shown that
with such high pressures and force of friction between the stylus and
the vinyl, that the outer skin layer of the record material melts as
the tip slides over the plastic and then refreezes almost as fast as
it melted.”

Looks as if the audio myth of "rest-between-playings" has been laid to
rest many moons ago.

Klaus

Seems to me that one urban myth has been laid to rest by yet another
urban myth. *I actually work from time to time with plasticized
vinyls. The melting point varies from formula to formula but I am
pretty sure we are talking about somewhere in the neighborhood of 300
to 350 degrees. That would mean the stylus would be sustaining
temepratures well in excess of 350 degrees if it is actually melting
the vinyl in the brief moment it is in contact with it at any given
point. And when I say well in excess I mean *way* well in in excess
given the extremely short duration of it's direct contact with any
single part of the vinyl. I am quite skeptical that the stylus and
subsequently the assmebly, the cateliver and the suspension are
sustaining these extreme temperatures for the duration of 20 minutes
or more when an entire record side is played. One would think that at
the very least, the dust and fine hairs that acumulate around the
stylus when one plays an uncleaned record would be going up in flames.
I doubt the cartridge could hold up under such conditions.- Hide quoted text -

- Show quoted text -

Oh, I dunno.

Try dragging a 340 (155 kg) weight concentrated on one square inch
(680 sq.mm) at a slow walking speed but continuously across an
unlubricated flat, smooth surface. See how much heat builds up. What
the stylus "sees" is exactly that at a microscopic level. And you have
to add the lateral travel at thousands of reversals per second. There
will be A LOT of friction developed. And that friction will be
expressed as heat, which will be absorbed by the entire system - but
not equally distributed.

Entirely apart from the heat, the vinyl does distort momentarily due
to being whacked by the stylus in passing, and whacked pretty damned
hard - again, imagine that 340 pound weight whacking you on top of the
head even at that slow walking speed. That distortion needs to recover
or the vinyl will fatigue and eventually fracture. Keep in mind that
as far as the stylus is concerned, the vinyl is the immoveable object.
As far as the vinyl is concerned, the stylus is the irresistable
force. Note also that historically records have been made of various
plastics rather than metal ( TIN foil was the original medium, but
lasted only a very few plays - for rather obvious reasons - Tin is an
extremely hard metal, but also quite brittle). This is exactly due to
the distortion-recovery (plastic) characteristics of those plastics
vs. metals which have no recovery abilities - they will either fatigue
or anneal under the typical playing conditions.

So, there are two issues at hand: The simple impact and the heat-due-
to-friction. Neither are particularly good for the vinyl if repeated
to often/closely together.

Peter Wieck
Melrose Park, PA

[Arny Krueger]

wrote in message

On Dec 10, 6:07 am, wrote:
Greg Wormald wrote:

"My memory made we wonder about the previous post on the
wearing of LP's by styli because I noticed they were
washing the test LP's fairly frequently with an alcohol
solution, and (probably) with inadequate rest
between playings."

G. Alexandrovich, “Disk recording and playback”,chapter
25 in “Handbook for sound engineers” by G. Ballou, 2nd
edition 1991

“Because of the small contact area that exists between
the stylus tip and the groove, the pressure against the
groove wall can rise up to many thousands of psi. For
instance, if each wall receives 0.7 gram of force
applied through the contact area equal to 2 ten
millionth of an inch, the pressure is 7726 psi. It has
been experimentally shown that with such high pressures
and force of friction between the stylus and the vinyl,
that the outer skin layer of the record material melts
as the tip slides over the plastic and then refreezes
almost as fast as it melted.”

Looks as if the audio myth of "rest-between-playings"
has been laid to rest many moons ago.

Seems to me that one urban myth has been laid to rest by
yet another urban myth.

No, they are still both in play. Two different processes that happen during
playing.

I actually work from time to time with plasticized vinyls. The melting
point varies
from formula to formula but I am pretty sure we are
talking about somewhere in the neighborhood of 300 to 350
degrees. That would mean the stylus would be sustaining
temepratures well in excess of 350 degrees if it is
actually melting the vinyl in the brief moment it is in
contact with it at any given point.

There's plenty of evidence that this happens, due to the incredibly tiny
contact point(s) between the stylus and the surface of the LP.

Do you have any experience with this sort of thing? Are you moving a point
that is as small as the contact area of a stylus over the surfaces you work
on? You are a makeup artist, if I recall correctly.

And when I say well
in excess I mean *way* well in in excess given the
extremely short duration of it's direct contact with any
single part of the vinyl.

The whole point (pun not intended) is that the contact is over one or two
very small areas.

I am quite skeptical that the
stylus and subsequently the assmebly, the cateliver and
the suspension are sustaining these extreme temperatures
for the duration of 20 minutes or more when an entire

That's because it doesn't happen that way. The heating is *very* localized.

The process that some of us are familiar with (perhaps not many from
southern California) relates to ice skating. The blade on skates is far
larger than a phono stylus, but it still heats the water enough due to
pressure, that the ice is melted where the blade contacts the ice. That's
one reason why skates slide across ice with such low resistance.

And BTW, ice skates don't warm up appreciably when this happens. For one
thing, the ice, like the vinyl LP, carries away a lot of the microscopic
amounts of heat that are involved.


record side is played. One would think that at the very
least, the dust and fine hairs that accumulate around the
stylus when one plays an uncleaned record would be going
up in flames.

Again, they are very large compared to the size of the area that is
involved.

I doubt the cartridge could hold up under
such conditions.

I doubt that critics of this process have any epxerience with other similar
processes in real life.

[[email protected]]

Hello Greg,

Greg Wormald wrote:

"It may have been put to rest--but the quote doesn't do it for me.
That
quote is about melting, and would also seem to contradict the
"minimal wear" research quoted earlier in the thread. I suspect that
melted vinyl would quite easily move under thousands of pounds of
pressure and distort the groove modulations, although I am not a
materials scientist at all.

The explanations I remember had to do with plastic deformation, and
fragility until the deformation had fully relaxed. Have you any
research
to suggest otherwise?"

Some time ago I have extracted some information from various papers
concerning record wear, which might be uesful in the context:

1. Barlow, “The limiting tracking weight of gramophone pickups for
negligible groove damage”, J. of Audio Eng. Soc. 1958, p.216

Limiting load for plastic deformation for a 1 mil tip in a 90 deg
groove is
0.64 gr. A 0.5 mil tip presents a side contact area of 23.4 square
microns.

2. Flom, “The deformation of plastics with hard, spherical indenters”,
J. of Audio Eng. Soc. 1959, p.122

Plastic deformation on vinyl occurs for a 0.005 cm stylus at 5 grams
static load.

3. Walton, “Gramophone record deformation”, Wireless World 1961, July,
p.353

Shows a graph with VTF vs stylus radius: plastic deformation is caused
for spherical styli of 0.0003 inch at 2.1 gr deformation, 0.0004
inch 2.7 gr, 0.0005 inch 3.1 gr etc.

4. Barlow, “Groove deformation in gramophone records”, Wireless World
1964, p.160

Presents a 25.4 micron stylus under increasing static load: not
calculated but observed

at 12 mg, fully elastic range
at 0.5 gr, plastic deformation just reaching the surface
at 2.5 gr, fully plastic range

5. Bastiaans, “Factors effecting the stylus/groove relationship in
phonograph playback systems”, J. of Audio Eng. Soc. 1967, p.389

Yield point of record plastics = 14,500 psi. Bastians refers to older
papers saying that in the stylus/groove contact, sub surface yielding
begins near a load of 0.150 gr and plastic yielding at 1 1.6 gr (for a
17.8 mil tip). Microscopic examination of a groove played with 2 gr
VTF revealed a slight permanent indentation track on both groove
walls.

Should you be interested in reading any of those papers, drop me a
mail.

To answer another question, Alexandrovich states: “It has been
suggested that since the melting temperature of the vinyl is about 480
ºF (249 ºC) that the same temperature exists in the contact area. If
the record material is metal, which happens when metal mothers are
played, then the pressure increases to 20,000 to 30,000 psi, and the
temperature can reach 2000 ºF (1093 ºC) because there is no plastic
deformation of the groove wall.”

Klaus

[[email protected]]

On Dec 11, 6:45*am, "Arny Krueger" wrote:
wrote in message







On Dec 10, 6:07 am, wrote:
Greg Wormald wrote:

"My memory made we wonder about the previous post on the
wearing of LP's by styli because I noticed they were
washing the test LP's fairly frequently with an alcohol
solution, and (probably) with inadequate rest
between playings."

G. Alexandrovich, “Disk recording and playback”,chapter
25 in “Handbook for sound engineers” by G. Ballou, 2nd
edition 1991

“Because of the small contact area that exists between
the stylus tip and the groove, the pressure against the
groove wall can rise up to many thousands of psi. For
instance, if each wall receives 0.7 gram of force
applied through the contact area equal to 2 ten
millionth of an inch, the pressure is 7726 psi. It has
been experimentally shown that with such high pressures
and force of friction between the stylus and the vinyl,
that the outer skin layer of the record material melts
as the tip slides over the plastic and then refreezes
almost as fast as it melted.”

Looks as if the audio myth of "rest-between-playings"
has been laid to rest many moons ago.
Seems to me that one urban myth has been laid to rest by
yet another urban myth.

No, they are still both in play. Two different processes that happen during
playing.

I actually work from time to time with plasticized vinyls. The melting
point varies
from formula to formula but I am pretty sure we are
talking about somewhere in the neighborhood of 300 to 350
degrees. That would mean the stylus would be sustaining
temepratures well in excess of 350 degrees if it is
actually melting the vinyl in the brief moment it is in
contact with it at any given point.

There's plenty of evidence that this happens, due to the incredibly tiny
contact point(s) between the stylus and the surface of the LP.

Where is this alleged "evidence?" I have seen plenty of hypothesis but
no actual evidence.


Do you have any experience with this sort of thing? Are you moving a point
that is as small as the contact area of a stylus over the surfaces you work
on? * You are a makeup artist, if I recall correctly.

I have a great deal of experience with the melting temperatures of
vinyls. Molten vinyl is not like boing water. It's really dangerously
hot. That was the point of citing my experience. Vinyl melts at a
relatively high temperature.


And when I say well
in excess I mean *way* well in in excess given the
extremely short duration of it's direct contact with any
single part of the vinyl.

The whole point (pun not intended) is that the contact is over one or two
very small areas.

Not all that small realtive to the size of the stylus. This is a
significant point. (pun intended)


I am quite skeptical that the
stylus and subsequently the assmebly, the cateliver and
the suspension are sustaining these extreme temperatures
for the duration of 20 minutes or more when an entire

That's because it doesn't happen that way. *The heating is *very* localized.

But it does happen that way if the action of the stylus tracking the
groove is genrating so much heat that it melts the vinyl in a near
instantanious contact time with the vinyl. while each part of the
vinyl that is being melted is in contact with the stylus for an
extremely brief moment, the stylus is in contact with the vinyl for
the entire duration of playing an entire side of a record. That means
the stylus would be subject to heat in excess of 350 degrees for as
much as 25 minutes with the right records. The stylus/ cantelive
assembly is very small. what is preventing it from heating up?


The process that some of us are familiar with (perhaps not many from
southern California) relates to ice skating. The blade on skates is far
larger than a phono stylus, but it still heats the water enough due to
pressure, that the ice is melted where the blade contacts the ice. That's
one reason why skates slide across ice with such low resistance.

And BTW, ice skates don't warm up appreciably when this happens. For one
thing, the ice, *like the vinyl LP, carries away a lot of the microscopic
amounts of heat that are involved.

Terrible analogy. You do realize that a stylus and an LP are start at
several hundred degrees below the melting temperature of vinyl no? You
do realize that an Ice skate starts out *above* the melting
temperature of ice in your garden variety ice skating rink don't you?
You do realize that unlike an LP the ice itself in an ice skating rink
is pretty near it's melting temperature don't you? Of course the blade
doesn't heat up. If anything it will cool down. The reasons should be
fairly obvious. The difference between your analogy and the stylus /
vinyl interface should be fairly obvious as well. Maybe if we used a
more comparable analogy than ice. That would be something that melts
at 350 degrees or more. There is no getting around the simple fact
that if the vinyl is actually melting form such a brief momnet of
contact that there is a relatively enormous amount of heat being
generated at the contact point *and* the sylus and subseqeuently the
whole assembly and anything touching it for any extended period of
time is being exposed to very high temperatures. Why isn't the duct
and fine hairs one can find attached to the stylus after playing a
record not catching fire? What is holding the stylus/cateliver assmbly
together under such extreme temperatutes? The rate of exansion
difference alone should cause the assembly to fail not to mention the
adhesive is not likely capable of remaining stable under such high
temperatures. what is preventing these high temperatures from causing
the rubber suspension to fail? It doesn't add up.

record side is played. One would think that at the very
least, the dust and fine hairs that accumulate around the
stylus when one plays an uncleaned record would be going
up in flames.

Again, they are very large compared to the size of the area that is
involved.

Not really. Besides it doesn't take a large area to *start* a fire. A
child with a magnifying glass can start a brush fire.


I doubt the cartridge could hold up under
such conditions.

I doubt that critics of this process have any epxerience with other similar
processes in real life

What process? I see a hypothesis without any supporting experimental
data.

[Arny Krueger]

wrote in message

On Dec 11, 6:45 am, "Arny Krueger"
wrote:
wrote in message







On Dec 10, 6:07 am, wrote:
Greg Wormald wrote:

"My memory made we wonder about the previous post on
the wearing of LP's by styli because I noticed they
were washing the test LP's fairly frequently with an
alcohol solution, and (probably) with inadequate rest
between playings."

G. Alexandrovich, “Disk recording and playback”,chapter
25 in “Handbook for sound engineers” by G. Ballou, 2nd
edition 1991

“Because of the small contact area that exists between
the stylus tip and the groove, the pressure against the
groove wall can rise up to many thousands of psi. For
instance, if each wall receives 0.7 gram of force
applied through the contact area equal to 2 ten
millionth of an inch, the pressure is 7726 psi. It has
been experimentally shown that with such high pressures
and force of friction between the stylus and the vinyl,
that the outer skin layer of the record material melts
as the tip slides over the plastic and then refreezes
almost as fast as it melted.”

Looks as if the audio myth of "rest-between-playings"
has been laid to rest many moons ago.
Seems to me that one urban myth has been laid to rest by
yet another urban myth.

No, they are still both in play. Two different processes
that happen during playing.

I actually work from time to time with plasticized
vinyls. The melting point varies
from formula to formula but I am pretty sure we are
talking about somewhere in the neighborhood of 300 to
350
degrees. That would mean the stylus would be sustaining
temepratures well in excess of 350 degrees if it is
actually melting the vinyl in the brief moment it is in
contact with it at any given point.

There's plenty of evidence that this happens, due to the
incredibly tiny contact point(s) between the stylus and
the surface of the LP.

Where is this alleged "evidence?" I have seen plenty of
hypothesis but no actual evidence.

That's because you didn't do your homework with the cites.

Do you have any experience with this sort of thing? Are
you moving a point that is as small as the contact area
of a stylus over the surfaces you work on? You are a
makeup artist, if I recall correctly.

I have a great deal of experience with the melting
temperatures of vinyls. Molten vinyl is not like boing
water. It's really dangerously hot. That was the point of
citing my experience. Vinyl melts at a relatively high
temperature.

I have a great deal of experience with the melting temperatures of vinyls.
On the scale of common materials, they are relatively low. This matter, as
it applies to LPs was fully discussed in the consumer and technical
literature of the day, some of which has been cited.

We're seeing here a not-uncommon trend - people who were too young or too
uninvolved with using vinyl in the days when it was mainstream, questioning
information that was relatively common knowlege among technicans and
more-involved audiophiles when the vinyl LP was mainstream technology.

The whole point (pun not intended) is that the contact is over one or two
very small areas.

Not all that small realtive to the size of the stylus.

Yes it is. The problem here is again someone not doing their homework and
failing to understand the miniscule size of the contact patch as compared to
even the seeming small size of the diamond stylus assembly.

Also, focusing on the size of the stylus ignores the role of the relatively
huge vinyl LP itself as a dissipator of heat.

I am quite skeptical that the
stylus and subsequently the assmebly, the cateliver and
the suspension are sustaining these extreme temperatures
for the duration of 20 minutes or more when an entire

That's because it doesn't happen that way. The heating
is *very* localized.

But it does happen that way if the action of the stylus
tracking the groove is genrating so much heat that it
melts the vinyl in a near instantanious contact time with
the vinyl.

Again, more evidence of someone not doing their homework. I strongly
recommend that you try to understand the process in terms that you can
understand more clearly. Perhaps you should multiply the size of the diamond
stylus to the point where a spherical stylus is the size of a bowling ball,
and compare that to the actual size of the contact patches.

[[email protected]]

On Dec 13, 7:34*am, "Arny Krueger" wrote:
wrote in message







On Dec 11, 6:45 am, "Arny Krueger"
wrote:
wrote in message



On Dec 10, 6:07 am, wrote:
Greg Wormald wrote:

"My memory made we wonder about the previous post on
the wearing of LP's by styli because I noticed they
were washing the test LP's fairly frequently with an
alcohol solution, and (probably) with inadequate rest
between playings."

G. Alexandrovich, “Disk recording and playback”,chapter
25 in “Handbook for sound engineers” by G. Ballou, 2nd
edition 1991

“Because of the small contact area that exists between
the stylus tip and the groove, the pressure against the
groove wall can rise up to many thousands of psi. For
instance, if each wall receives 0.7 gram of force
applied through the contact area equal to 2 ten
millionth of an inch, the pressure is 7726 psi. It has
been experimentally shown that with such high pressures
and force of friction between the stylus and the vinyl,
that the outer skin layer of the record material melts
as the tip slides over the plastic and then refreezes
almost as fast as it melted.”

Looks as if the audio myth of "rest-between-playings"
has been laid to rest many moons ago.
Seems to me that one urban myth has been laid to rest by
yet another urban myth.

No, they are still both in play. Two different processes
that happen during playing.

I actually work from time to time with plasticized
vinyls. The melting point varies
from formula to formula but I am pretty sure we are
talking about somewhere in the neighborhood of 300 to
350
degrees. That would mean the stylus would be sustaining
temepratures well in excess of 350 degrees if it is
actually melting the vinyl in the brief moment it is in
contact with it at any given point.
There's plenty of evidence that this happens, due to the
incredibly tiny contact point(s) between the stylus and
the surface of the LP.
Where is this alleged "evidence?" I have seen plenty of
hypothesis but no actual evidence.

That's because you didn't do your homework with the cites.

the question is where is the evidence. the answer you offer is pure ad
hominem. That does not advance the discussion.



Do you have any experience with this sort of thing? Are
you moving a point that is as small as the contact area
of a stylus over the surfaces you work on? You are a
makeup artist, if I recall correctly.
I have a great deal of experience with the melting
temperatures of vinyls. Molten vinyl is not like boing
water. It's really dangerously hot. That was the point of
citing my experience. Vinyl melts at a relatively high
temperature.

I have a great deal of experience with the melting temperatures of vinyls.
On the scale of common materials, they are relatively low.

You compared it to ice.

This matter, as
it applies to LPs was fully discussed in the consumer and technical
literature of the day, some of which has been cited.

Are you disputing my assertions about the melting temperatures of
vinyls? What point are you trying to make here?



We're seeing here a not-uncommon trend - people who were too young or too
uninvolved with using vinyl in the days when it was mainstream, questioning
information that was relatively common knowlege among technicans and
more-involved audiophiles when the vinyl LP was mainstream technology.



We are seeing here a not uncommon trend of adhominem and other logical
fallacies in place of reliable evidence and logical arguments. It does
nothing to advance any meaningful discussion. I se a huge problem with
the hypothesis that assert the vinyl is melting. So far you and nobody
else has offered anything to address the problems I have pointed out.



The whole point (pun not intended) is that the contact is over one or two
very small areas.
Not all that small realtive to the size of the stylus.

Yes it is. *The problem here is again someone not doing their homework and
failing to understand the miniscule size of the contact patch as compared to
even the seeming small size of the diamond stylus assembly.

Instead of posturing how about just backing this assertion with ome
meaningful data? It should be simple enough for someone as
knowledgable as you to lay out the math here. What would be the
predicted rise in temperature of a stylus based on the mass of the
stylus. the contact area that is being subjected to a constant heat
source in excess of 350 degrees and the material of the stylus. You
seem to think I am missing something so please fill in the blanks and
give us a prediction of the rise in tempurature of the stylus based on
the hypothesis you seem to believe to be true.



Also, focusing on the size of the stylus ignores the role of the relatively
huge vinyl LP itself as a dissipator of heat.

Um no. The heat generated from the friction goes in both directions.
Into the vinyl and into the sylus. Both surfaces are being subjected
to whatever rise in temperature is being generated by the stylus
tracking the groove. the difference is that each point on the vinyl is
subjected to the heat for a very short duration of time. The stylus
OTOH is subjected to that heat source for in excess of 25 minutes with
some LPs. Rub two things together they both get hot. the claim seems
to be that the temperature generated is hot enough to melt vinyl with
a near instantanious contact. That means the temperature at the stylus/
vinyl contact area is constantly in excess of 350 degrees.

I am quite skeptical that the
stylus and subsequently the assmebly, the cateliver and
the suspension are sustaining these extreme temperatures
for the duration of 20 minutes or more when an entire
That's because it doesn't happen that way. The heating
is *very* localized.
But it does happen that way if the action of the stylus
tracking the groove is genrating so much heat that it
melts the vinyl in a near instantanious contact time with
the vinyl.

Again, more evidence of someone not doing their homework.

Pure ad hominem.
I also note that you failed to address any of my questions. i believe
they are quite relavent so I will ask them again.
There is no getting around the simple fact
that if the vinyl is actually melting form such a brief momnet of
contact that there is a relatively enormous amount of heat being
generated at the contact point *and* the sylus and subseqeuently the
whole assembly and anything touching it for any extended period of
time is being exposed to very high temperatures. Why isn't the dust
and fine hairs one can find attached to the stylus after playing a
record not catching fire? What is holding the stylus/cateliver
assmbly
together under such extreme temperatutes? The rate of exansion
difference alone should cause the assembly to fail not to mention the
adhesive is not likely capable of remaining stable under such high
temperatures. what is preventing these high temperatures from causing
the rubber suspension to fail?

[[email protected]]

wrote:

"But it does happen that way if the action of the stylus tracking the
groove is generating so much heat that it melts the vinyl in a near
instantaneous contact time with the vinyl, while each part of the
vinyl that is being melted is in contact with the stylus for an
extremely brief moment, the stylus is in contact with the vinyl for
the entire duration of playing an entire side of a record. That means
the stylus would be subject to heat in excess of 350 degrees for as
much as 25 minutes with the right records. The stylus/ cantilever
assembly is very small. What is preventing it from heating up?"


[ I have cleaned up the quoting here. Please make quotes clear. dsr ]


First of all, melting temperature of record vinyl is 250 ºC, as
indicated by Alexandrovich. Further, diamond is a rather good heat
conductor, aluminium for instance has about 1/10th of the heat
conductivity of diamond and Boron has about 1/10th of that of
Aluminium (Al and B being two widely used cantilever materials). So
even IF the diamond heats up, for which there is no evidence, the
cantilever will probably not nor will cantilever suspension or
cartridge body.

As for the “duct and fine hairs one can find attached to the stylus
after playing a record not catching fire”, probably the ignition
temperature of those materials are not reached. Ignition temperature
of diamond is at about 650 ºC, so it won’t burn. On metal mothers
there is no melting, hence no dissipation of heat and “styli made of
diamond, which is nothing more than carbon, literally burn up or wear
out in a couple of hours when they are used to play metal mothers”,
says Alexandrovich.

Klaus

[[email protected]]

On Dec 13, 9:43 pm, wrote:
You seem to think I am missing something so
please fill in the blanks and give us a prediction
of the rise in tempurature of the stylus based on
the hypothesis you seem to believe to be true.

You ARE missing something, and it's crucial to
the understanding. Your simplified analysis, while
seeming intuitively correct, falls far short of physical
reality and thuis is flawed.

Two of the most important points your missing are
the concepts of thermal conductivity and specific heat.
These are the second-order that completely
overwhelm your first-order based model.

Let's assume your point that the frictional contact
does the same work on both the point of contact of
the diamond and the vinyl, which we will also assume
has the same area. The fact that the thermal conductivity
of diamond is nearly TEN THOUSAND TIMES that of
vinyl has a profound effect on what the effect of the same
heat applied to the diamond vs the vinyl. And, assuming
a simply aluminum cantilever, whose thermal conductivity
is some 1300 times that of vinyl, means that you have,
in the stylus and cantilever, a system which is far better
at dissipating the heat generated at the contact points.
So, all other things being equal, the same amount of heat
applied to that same surface area will be dissipated MUCH
more effectively in the stylus than in the vinyl.

The second effect you're missing is the specific heat
and effective heat capacity of the materials. From what
I can find, the specific heat of diamond is about twice that
of PVC (it's very formulation dependent). That means
for the same amount of thermal work applied to the same
mass of the two, the vinyl's temperature will rise twice as
much.

Now, the thermal conductivity essentially ensures that
the amount of mass affected by the rise in temperature
is kept small, because it can't conduct heat away fast
enough (considering JUST the diamond/vinyl interface,
the amount of mass difference is on the order of 10,000
to 1). The diamond, on the other hand, is far better at
conducting heat away.

The net effect is that the effective thermal mass of the
vinyl in a more comprehensive model is far LESS than
that of the diamond. And combine that with the slightly
lower heat capacity, the effect is that the same thermal
work applied to BOTH at the same time (which is not
necessarily the case) results in a far more dramatic
rise in temperature in the vinyl (by a WIDE margin)
than in the diamond stylus.

Also, focusing on the size of the stylus ignores the role of the relatively
huge vinyl LP itself as a dissipator of heat.

And, similarily, you ignore the fact that all that vinyl
mass is rendered irrelevant because of vinyl's exceedingly
poor thermal conductivity. If the heat isn't conducted there,
it might not even exist.

Remember the ratio is nearly 10,000 to 1. That's NOT
anything you can ignore.

Um no. The heat generated from the friction goes in both directions.
Into the vinyl and into the sylus. Both surfaces are being subjected
to whatever rise in temperature is being generated by the stylus
tracking the groove. the difference is that each point on the vinyl is
subjected to the heat for a very short duration of time.

And that's where your model falls apart. One can say that
it's reasonable assume that the same WORK is done on both.
But the VAST difference in the combination of thermal
conductivity and effective heat capacity now means the rise
in temperature in the vinyl is far in excess of that of the diamond.

If anything, the diamond is there to save the vinyl but,
as you mentioned, it's too late: the vinyl has moved on.

There is no getting around the simple fact
that if the vinyl is actually melting form such a brief momnet of
contact that there is a relatively enormous amount of heat being
generated at the contact point *and* the sylus

No, and your ignoring the effects of both thermal conductivity
and heat capacity might lead you to this conclusion,
but the coclusion is wrong.

and subseqeuently the
whole assembly and anything touching it for any extended period of
time is being exposed to very high temperatures.

Nope. Thermal conductivity and heat capacity account for
a FAR lower temperature on the stylus and a monentary
far HIGHER temperature on the vinyl.

Why isn't the dust
and fine hairs one can find attached to the stylus after playing a
record not catching fire?

Because, when a more complete model is considered, the
temperature is not very high.

What is holding the stylus/cateliver
assmbly
together under such extreme temperatutes?

The temperatures are not so extreme. Your neglect
of the thermal properties of the materials leads you
to an erroneous conclusion.

The rate of exansion
difference alone should cause the assembly to fail not to mention the
adhesive is not likely capable of remaining stable under such high
temperatures. what is preventing these high temperatures from causing
the rubber suspension to fail?

There's no problem, since the temperature you predict simply
doesn't happen.

But that does not preclude the temperature of the
vinyl from being substantially higher.

[vlad]

On Dec 14, 12:20*pm, wrote:
On Dec 13, 9:43 pm, wrote:

You seem to think I am missing something so
please fill in the blanks and give us a prediction
of the rise in tempurature of the stylus based on
the hypothesis you seem to believe to be true.

. . .

But that does not preclude the temperature of the
vinyl from being substantially higher.

Richard,

thanks for informative reply. One thing is not clear - is vinyl
melting or not at the point of contact? Did anybody look close into
this issue?

Thx

vlad

[Sonnova]

On Sun, 14 Dec 2008 18:37:19 -0800, vlad wrote
(in article ):

On Dec 14, 12:20*pm, wrote:
On Dec 13, 9:43 pm, wrote:

You seem to think I am missing something so
please fill in the blanks and give us a prediction
of the rise in tempurature of the stylus based on
the hypothesis you seem to believe to be true.

. . .

But that does not preclude the temperature of the
vinyl from being substantially higher.

Richard,

thanks for informative reply. One thing is not clear - is vinyl
melting or not at the point of contact? Did anybody look close into
this issue?

Thx

vlad




No, It's not melting but it does get "plastic" and is momentarily deformed.

[[email protected]]

On Dec 14, 9:37 pm, vlad wrote:
On Dec 14, 12:20 pm, wrote: On Dec 13, 9:43 pm, wrote:

You seem to think I am missing something so
please fill in the blanks and give us a prediction
of the rise in tempurature of the stylus based on
the hypothesis you seem to believe to be true.

. . .

But that does not preclude the temperature of the
vinyl from being substantially higher.

Richard,

thanks for informative reply. One thing is not clear - is vinyl
melting or not at the point of contact? Did anybody look close into
this issue?

Under "normal" conditions, maybe, maybe not. It's
not clear what happens on the top few molecules
of the surface at the point of interface, and it's not
clear that if melting point is exceeded at that point
whether it is destructive or not. But I have seen
scanning micrographs of vinyl grooves showing clear
and unmistakable evidence of melting to the point of
being unambiguously destructive. WHat the exact
conditions at play are I don't recall. If I happen upon
any of these images on the web, I'll post them (if I
remember this conversation).

[[email protected]]

On Dec 14, 9:37 pm, vlad wrote:
thanks for informative reply. One thing is not clear - is vinyl
melting or not at the point of contact? Did anybody look close into
this issue?

Well, I just did a simple search, and here's one finding:

http://www.micrographia.com/projec/p...y/viny0200.htm

[Peter Wieck]

On Dec 14, 11:10*pm, Sonnova wrote:

No, It's not melting but it does get "plastic" and is momentarily
deformed.

Exactly this. Melting *CAN* (and does) occur under abusive conditions
or in certain types of failure modes. But for the purposes of this
discussion, melting is not typical. On the face of it, this is rather
obvious.

However, the number of 340psi does seem to be a commonly used -
average- number. That is a lot of weight on a small area moving at
some speed on an un-lubricated smooth surface.

That vinyl does get distorted and at least warmed considerably by the
impact of the stylus. Plastics do have a recovery mode that if over-
stressed ends in failure (crumbling). Why would one lean into a punch
and test those recovery limits?

For the record, 3021.27 angels can dance on the head of the typical
seamstress pin.

Peter Wieck
Melrose Park, PA

[Steven Sullivan]

Here's the 1980 article showing scanning electron micrographs of LP
wear.

http://www.badongo.com/file/12497545

--
-S
I know that most men, including those at ease with problems of the greatest complexity, can
seldom accept the simplest and most obvious truth if it be such as would oblige them to admit
the falsity of conclusions which they have proudly taught to others, and which they have
woven, thread by thread, into the fabrics of their life -- Leo Tolstoy

[C. Leeds]

In message
wrote:

There is no getting around the simple fact
that if the vinyl is actually melting form such a brief momnet of
contact that there is a relatively enormous amount of heat being
generated at the contact point *and* the sylus and subseqeuently the
whole assembly and anything touching it for any extended period of
time is being exposed to very high temperatures. Why isn't the dust
and fine hairs one can find attached to the stylus after playing a
record not catching fire? What is holding the stylus/cateliver
assmbly
together under such extreme temperatutes? The rate of exansion
difference alone should cause the assembly to fail not to mention the
adhesive is not likely capable of remaining stable under such high
temperatures. what is preventing these high temperatures from causing
the rubber suspension to fail?

The claim that a stylus melts the vinyl passing beneath it is just
absurd urban legend. It is perpetuated by those who - for some odd
reason - are simply driven to distraction by the simple fact that
millions of people still enjoy LPs. We're what one contributor here
repeatedly calls "a noisy minority." So, there are those who noisily
oppose the LP. They are on a crusade. The melting vinyl claim is just a
part of their anti-LP mission.

[Steven Sullivan]

C. Leeds wrote:
In message
wrote:

There is no getting around the simple fact
that if the vinyl is actually melting form such a brief momnet of
contact that there is a relatively enormous amount of heat being
generated at the contact point *and* the sylus and subseqeuently the
whole assembly and anything touching it for any extended period of
time is being exposed to very high temperatures. Why isn't the dust
and fine hairs one can find attached to the stylus after playing a
record not catching fire? What is holding the stylus/cateliver
assmbly
together under such extreme temperatutes? The rate of exansion
difference alone should cause the assembly to fail not to mention the
adhesive is not likely capable of remaining stable under such high
temperatures. what is preventing these high temperatures from causing
the rubber suspension to fail?

The claim that a stylus melts the vinyl passing beneath it is just
absurd urban legend. It is perpetuated by those who - for some odd
reason - are simply driven to distraction by the simple fact that
millions of people still enjoy LPs. We're what one contributor here
repeatedly calls "a noisy minority." So, there are those who noisily
oppose the LP. They are on a crusade. The melting vinyl claim is just a
part of their anti-LP mission.

From the SEM article, the evidence is that styli do not 'melt'
vinyl in a way likely to eb audibly appreciable, but they do
*fracture* vinyl in ways that are potentially audibly degradative.



--
-S
I know that most men, including those at ease with problems of the greatest complexity, can
seldom accept the simplest and most obvious truth if it be such as would oblige them to admit
the falsity of conclusions which they have proudly taught to others, and which they have
woven, thread by thread, into the fabrics of their life -- Leo Tolstoy

[Arny Krueger]

"C. Leeds" wrote in message

In message
wrote:

There is no getting around the simple fact
that if the vinyl is actually melting form such a brief
momnet of contact that there is a relatively enormous
amount of heat being generated at the contact point
*and* the sylus and subseqeuently the whole assembly and
anything touching it for any extended period of time is
being exposed to very high temperatures.

I guess you didn't read the post where I worked out the geometry of the
situation.

Executive summary: The area being melted is like two 5 inch squares on the
surface of a 100+ foot diameter ball.

The claim that a stylus melts the vinyl passing beneath
it is just absurd urban legend.

Absurd urban legends that get published in refereed scientific journals.

It is perpetuated by
those who - for some odd reason - are simply driven to
distraction by the simple fact that millions of people
still enjoy LPs.

Yes, that was the motivation back in the 1970s when a lot of this was
published.