What Is "Alloy"?

Ben C said:

On 2008-04-09, Michael Press <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Pure Al is also used very effectively in metal sandwiches for cookware.

Internal layer of stainless steel.
Middle layer pure Al.
External layer of Al alloy or stainless steel.

What's the point of having the three layers like that? Something to do
with heat capacity or conduction?

Stainless is non-reactive with food, but has relatively poor thermal
conductivity. Aluminum can change the flavor of food, stain/discolor and
scratches easily. SS "clad" Al is the best of both worlds. A less
expensive approach is to just bond an Al disk to the bottom of a SS
pot/pan. I have several pots/pans of both styles and prefer the disc
over the clad, I don't think sidewall conductivity makes much of a
difference, probably only with saute pan over a gas burner.

Michael Press said:

Ben C said:

What's the point of having the three layers like that? Something to do
with heat capacity or conduction?

Yes. Best heat conduction is
1. Ag
2. Cu
3. Al

You left out #1 by a wide margin, diamond.

I'm looking forward to black diamond heat spreaders on kitchenware and
black diamond heat sinks on electronics. LED bike lights might be
better with transparent diamond heat sinks for better all-angle
visibility.

Chalo

Chalo said:

Michael Press said:

Ben C said:

What's the point of having the three layers like that? Something to do
with heat capacity or conduction?

Yes. Best heat conduction is
1. Ag
2. Cu
3. Al

You left out #1 by a wide margin, diamond.

And gold which is possibly better than silver.

Quoted message said:

I'm looking forward to black diamond heat spreaders on kitchenware and
black diamond heat sinks on electronics.

What's a black diamond?

Ben C said:

Chalo said:

Michael Press said:

Ben C wrote:
>
> What's the point of having the three layers like that? Something to do
> with heat capacity or conduction?

Yes. Best heat conduction is
1. Ag
2. Cu
3. Al

You left out #1 by a wide margin, diamond.

And gold which is possibly better than silver.

Quoted message said:

I'm looking forward to black diamond heat spreaders on kitchenware and
black diamond heat sinks on electronics.

What's a black diamond?

Dear Ben,

"A black synthetic diamond, specifically CVD polycrystalline diamonds
or HPHT polycrystalline compact diamonds."

http://en.wikipedia.org/wiki/Black_diamond

Cheers,

Carl Fogel

In article <[email hidden]>,

Agent Smith said:

Does anybody know the name (or names) of the famous alloy from which
high- end racing components are made? :] Whenever I see it referred
to in books and articles, it is just called "alloy," but apparently
there's a whole branch of engineering that's embodied in that single
word, and writers gloss over the whole subject when they say that.

Ask the r.b.t. ex-metallurgist. He should have that knowledge right at
his fingertips, this being the sort of thing that metallurgists and
ex-metallurgists are supposed to know.

Ben C said:

Chalo said:

Michael Press wrote:

Quoted message said:

Quoted message said:

Ben C wrote:

Quoted message said:

Quoted message said:

> What's the point of having the three layers like that? Something to do
> with heat capacity or conduction?

Quoted message said:

Quoted message said:

Yes. Best heat conduction is
1. Ag
2. Cu
3. Al

Quoted message said:

You left out #1 by a wide margin, diamond.

And gold which is possibly better than silver.

Nope. Silver beats gold. But gold does beat aluminum. And as Chalo
says, diamond beats all. But surprising to me is that there's some
carbon fiber that's supposedly better than silver. Matweb lists
"Cytec Thornel® P-120 2K Carbon Fiber, Pitch Precursor" as over 4000
BTU-in/(hr-ft²-°F). That'll be the fiber itself, not the fiber bound
in a matrix of epoxy etc., I'm sure.

Matweb is a good online source for material properties.
http://www.matweb.com/search/PropertySearch.aspx

- Frank Krygowski

On Thu, 10 Apr 2008 08:40:52 -0700 (PDT), [email hidden] may have

Quoted message said:

On Apr 10, 4:19 am, "[email hidden]" <[email hidden]>

Quoted message said:

I've decided to
put an end to the Scharf-Krygowski flamewars about
bicycle lights and halogens versus generators by
building a 6.5-meter aluminized reflecting headlamp.
Proper figuring will insure a good beam pattern
for either halogen or generator-powered sources.

Cool!

But with that thing, you _will_ want to waste plenty of light by
sending it upward, rather than onto the road. Otherwise, the next
time you pass under a bridge, you'll lose the top few meters of your
reflector.

(BTW, my generator lamps do have halogen bulbs. The flamewars are
mostly about using efficient optics vs. brutishly spraying lumens
everywhere.)

But brutishly spraying lumens everywhere is just the achetypical Great
American Way Theory as applied to the subject of illumination of the
road. Nothing but wretched excess is good enough!

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

On Wed, 9 Apr 2008 23:04:20 -0400, "Sandy" <[email hidden]> may have

Quoted message said:

Dans le message de news:[email hidden],
[email hidden] <[email hidden]> a
réfléchi, et puis a déclaré :

Quoted message said:

Tom Sherman said:

>> Does anybody know the name (or names) of the famous alloy from
>> which high-end racing components are made? :] Whenever I see it
>> referred to in books and articles, it is just called "alloy," but
>> apparently there's a whole branch of engineering that's embodied
>> in that single word, and writers gloss over the whole subject when
>> they say that.

Quoted message said:

> just like "plastic".

Quoted message said:

When I read "plastic", my first thought is non-recoverable
deformation. People do look at me weirdly for using "polymer" in
regular conversation.

The "plastic" battle is over as I see it. Plastic has been part of
English vernacular so long and with reasonable cause that, without
modifiers, it means a nonmetallic polymer. I doesn't lead to
misinterpretation as "alloy" does with metals, especially aluminum.

http://www.merriam-webster.com/dictionary/plastic

Jobst Brandt

So, I suppose you would not be offended to know that the original meaning
has nothing to do with your understanding, e.g., the "plastic arts". Like
alloy, which ain't aluminium.

I have heard more than just Americans use the term "alloy" to refer
generically to any metal that is not obviously iron or common steel,
usually including plain aluminum (whose alloys aren't typically
obvious.) (I will not that there seems to be an assumption by many
who understand the term "alloy" that iron and other single-substance
metals are seldom employed now, and vuirtually everything metal is
actually made of an alloy of some sort.) OTOH, copper[1] usually gets
identified correctly...but ask the metallurgically illiterate if brass
is an alloy, and my experience has been that you've got about a 50-50
chance of getting a correct answer.

[1] Among those who count themselves as fishermen or equipment repair
personnel of any stripe, lead also usually gets identified
correctly...but I've been amazed to discover that this facility with
material recognition is a skill that is no longer ubiquitous in the
population in general. I have met more than a few folks who have
never seen liquid mercury at all, for instance.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

On 09 Apr 2008 19:14:32 GMT, [email hidden] may have

Quoted message said:

Tom Sherman said:

Quoted message said:

Does anybody know the name (or names) of the famous alloy from
which high- end racing components are made? :] Whenever I see it
referred to in books and articles, it is just called "alloy," but
apparently there's a whole branch of engineering that's embodied in
that single word, and writers gloss over the whole subject when
they say that.

Quoted message said:

Metals should be referred to by their proper names, e.g. 6061-T6
aluminium alloy, 4130 chromium-molybdenum steel.

Quoted message said:

Unalloyed aluminium is a very poor structural material and is used
mostly for corrosion resistant cladding.

General use has lead to the use of "Alloy" when Aluminum is meant,
probably because it is a shorter word, while mag is used for aluminum
(aluminium) or magnesium alloy automobile wheels. The broad use of
"alloy" in lieu of aluminum is especially common in bicycling.

English isn't getting better with such slang although the excuse "You
know what I mean" is invoked to justify sloppy talk. I get the
impression that most of the alloy-folks don't know what an alloy is.

http://www.merriam-webster.com/dictionary/alloy

You're not the only one. I've encountered a broader range of
application of "alloy", though, and in many instances it seems to be
due to an assumption that old single-substance metals are simply not
used very much anymore, therefore anything good that's made of metal
is probably made using an alloy. However, the common substitution of
"alloy" for "aluminum" (and I agree that it's very frequently used)
may also have something to do with the way that people who know the
actual composition of a given component may use an inexact or
misleading term intentionally by way of misdirection, rather than
supposedly giving their competitors any information that might be
useful. I recall reports of a certain press gathering in Europe back
when Porsche first put an aluminim-bodied 911-derived car on the
circuit. One of the drivers was getting badgered by several of the
press concerning what the car was made of, and he finally old them
"unobtainium". Reportedly, at least one of the journalists asked how
to spell it.

Needless secrecy can lead to common misunderstanding.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Quoted message said:

On Apr 10, 4:19 am, "[email hidden]" <[email hidden]>

Quoted message said:

I've decided to
put an end to the Scharf-Krygowski flamewars about
bicycle lights and halogens versus generators by
building a 6.5-meter aluminized reflecting headlamp.
Proper figuring will insure a good beam pattern
for either halogen or generator-powered sources.

Cool!

But with that thing, you _will_ want to waste plenty of light by
sending it upward, rather than onto the road.  Otherwise, the next
time you pass under a bridge, you'll lose the top few meters of your
reflector.

On the contrary, as an astronomer, I am extremely
sensitive to light pollution issues. Properly baffled
light sources are very important.

Bridges? We don't need no stinkin' bridges!

Quoted message said:

(BTW, my generator lamps do have halogen bulbs.  The flamewars are
mostly about using efficient optics vs. brutishly spraying lumens
everywhere.)

OK, generators vs. batteries, big headlamps vs.
MR housings, whatever. Scharf would describe the
flamewars differently from you. Fortunately, my
spun-cast borosilicate light-weighted reflector will
make such petty considerations a thing of the past:

http://mirrorlab.as.arizona.edu/

Ben

In article <wuKLj.1$nT1.0@trndny09>,

Peter Cole said:

Ben C said:

On 2008-04-09, Michael Press <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Pure Al is also used very effectively in metal sandwiches for cookware.

Internal layer of stainless steel.
Middle layer pure Al.
External layer of Al alloy or stainless steel.

What's the point of having the three layers like that? Something to do
with heat capacity or conduction?

Stainless is non-reactive with food, but has relatively poor thermal
conductivity. Aluminum can change the flavor of food, stain/discolor and
scratches easily. SS "clad" Al is the best of both worlds. A less
expensive approach is to just bond an Al disk to the bottom of a SS
pot/pan. I have several pots/pans of both styles and prefer the disc
over the clad, I don't think sidewall conductivity makes much of a
difference, probably only with saute pan over a gas burner.

There you go thinking again.

--
Michael Press

In article <[email hidden]>,

Ben C said:

Chalo said:

Michael Press said:

Ben C wrote:
>
> What's the point of having the three layers like that? Something to do
> with heat capacity or conduction?

Yes. Best heat conduction is
1. Ag
2. Cu
3. Al

You left out #1 by a wide margin, diamond.

And gold which is possibly better than silver.

No it conducts heat slower than Ag and Cu.

--
Michael Press

Quoted message said:

Quoted message said:

Ben C? wrote:

Quoted message said:

Quoted message said:

> Pure Al is also used very effectively in metal sandwiches for
> cookware.
> Internal layer of stainless steel.
> Middle layer pure Al.
> External layer of Al alloy or stainless steel.
What's the point of having the three layers like that? Something to
do with heat capacity or conduction?

People like stainless steel cookware and would like it to behave well
by not burning food on hot spots, sometimes in the shape of the gas
flame or electric coils under the pot. An aluminum core this gives
the user a stainless steel pot with good lateral conductivity (without
hot spots). Many people see aluminum as dangerous to health as lead
and avoid cooking food in aluminum pots.

I am in strong agreement about the improvement that
an aluminum core makes to stainless steel cookware
(for those of you following along, an example is the
classic variety of Farberware: stainless steel pots
with an aluminum disc underneath for heat conduction
and a stainless steel bottom layer for cleaning,
scratch and corrosion resistance).

I don't think there is strong evidence that aluminum
cookware is dangerous to health. Some years ago,
there was a scare because Alzheimer's patients tend to
have aluminum deposits in their brains. However, it is
considered more likely that Alzheimer's leads to the
accumulation of aluminum than that the aluminum
causes Alzheimer's.

This may be interesting, if you like extrapolating from samples of one.
UK death certificates show a primary cause of death (according to the
doctor completing it) and any other illnesses present. I once processed
the death certificate of an customer where the guy had died from a
stroke or something fairly commonplace, but Alzheimer's disease was also
mentioned on the certificate.

His occupation was given as "Manager of aluminium smelting plant, retired".

Quoted message said:

Quoted message said:

On Apr 10, 4:19 am, "[email hidden]" <[email hidden]>

Quoted message said:

�I've decided to
put an end to the Scharf-Krygowski flamewars about
bicycle lights and halogens versus generators by
building a 6.5-meter aluminized reflecting headlamp.
Proper figuring will insure a good beam pattern
for either halogen or generator-powered sources.

Cool!

But with that thing, you _will_ want to waste plenty of light by
sending it upward, rather than onto the road. �Otherwise, the next
time you pass under a bridge, you'll lose the top few meters of your
reflector.

On the contrary, as an astronomer, I am extremely
sensitive to light pollution issues. Properly baffled
light sources are very important.

Bridges? We don't need no stinkin' bridges!

Quoted message said:

(BTW, my generator lamps do have halogen bulbs. �The flamewars are
mostly about using efficient optics vs. brutishly spraying lumens
everywhere.)

OK, generators vs. batteries, big headlamps vs.
MR housings, whatever. Scharf would describe the
flamewars differently from you. Fortunately, my
spun-cast borosilicate light-weighted reflector will
make such petty considerations a thing of the past:

http://mirrorlab.as.arizona.edu/

Ben

utterly cool.

how long to cast?
how long to anneal?
how long to grind and polish?

and, how much does 8.4m cost???

awesome stuff.

"Ben C" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Chalo said:

Michael Press said:

Ben C wrote:
>
> What's the point of having the three layers like that? Something to

do

Quoted message said:

Quoted message said:

Quoted message said:

> with heat capacity or conduction?

Yes. Best heat conduction is
1. Ag
2. Cu
3. Al

You left out #1 by a wide margin, diamond.

And gold which is possibly better than silver.

Quoted message said:

I'm looking forward to black diamond heat spreaders on kitchenware and
black diamond heat sinks on electronics.

What's a black diamond?

Black Diamond is a trade name of Diamond Black, Inc. for their PVD boron
carbide coating:

http://www.finishing.com/0400-0599/582.shtml

It was developed as a "miracle coating" for metal cutting tools but fell
out of favor because of inconsistent results.

Chas.

On Apr 12, 12:18 am, "[email hidden]" <[email hidden]>

Quoted message said:

Quoted message said:

But with that thing, you _will_ want to waste plenty of light by
sending it upward, rather than onto the road. Otherwise, the next
time you pass under a bridge, you'll lose the top few meters of your
reflector.

On the contrary, as an astronomer, I am extremely
sensitive to light pollution issues. Properly baffled
light sources are very important.

Off topic, but I strongly agree.

I grew up in city/suburbs, but still loved the night sky. I recall
when the local planetarium opened, and the astronomer projected a
synthetic sky I'd never seen, with no constellations I could
recognize. He then dimmed all the stars, and at about half power,
things looked "normal."

And I recall my first trip west, when I first learned saw the Milky
Way, plus a million other stars. And when I first learned that M81
was, indeed, visible to my naked eye. I literally saw what I'd been
missing.

Sadly, my telescope's a lot less fun since the U.S.Postal "Service"
took over residential property ("We're exempt from your zoning laws"😉
and erected tall, unbaffled all-night parking lot lights about 100
yards away.

- Frank Krygowski

Peter Cole said:

Quoted message said:

Quoted message said:

Pure Al is also used very effectively in metal sandwiches for cookware.

Quoted message said:

Quoted message said:

Quoted message said:

Internal layer of stainless steel.
Middle layer pure Al.
External layer of Al alloy or stainless steel.

Quoted message said:

Quoted message said:

What's the point of having the three layers like that? Something
to do with heat capacity or conduction?

Quoted message said:

Stainless is non-reactive with food, but has relatively poor thermal
conductivity. Aluminum can change the flavor of food,
stain/discolor and scratches easily. SS "clad" Al is the best of
both worlds. A less expensive approach is to just bond an Al disk
to the bottom of a SS pot/pan. I have several pots/pans of both
styles and prefer the disc over the clad, I don't think sidewall
conductivity makes much of a difference, probably only with saute
pan over a gas burner.

The value of sidewall conductivity is apparent with liquids because
gas flames wrap around the pot and rise up the sides. This causes a
scorched ring inside the pot where the liquid being heated burns at
its surface, the free part of the pot not in contact with the soup
becomes flame-hot. A pot with sidewall conductivity does not do this.

I experienced this often with old style "Revere Ware".

http://tinyurl.com/64fo96

Jobst Brandt

On Sat, 12 Apr 2008 08:13:17 -0700 (PDT), [email hidden] may have

Quoted message said:

On Apr 12, 12:18 am, "[email hidden]" <[email hidden]>

Quoted message said:

Quoted message said:

But with that thing, you _will_ want to waste plenty of light by
sending it upward, rather than onto the road. Otherwise, the next
time you pass under a bridge, you'll lose the top few meters of your
reflector.

On the contrary, as an astronomer, I am extremely
sensitive to light pollution issues. Properly baffled
light sources are very important.

Off topic, but I strongly agree.

I grew up in city/suburbs, but still loved the night sky. I recall
when the local planetarium opened, and the astronomer projected a
synthetic sky I'd never seen, with no constellations I could
recognize. He then dimmed all the stars, and at about half power,
things looked "normal."

And I recall my first trip west, when I first learned saw the Milky
Way, plus a million other stars. And when I first learned that M81
was, indeed, visible to my naked eye. I literally saw what I'd been
missing.

In the aftermath of Hurricane Andrew, light pollution in southern Dade
County, Florida was drastically reduced, and many people there saw the
true night sky for the first time in their lives. The reaction was
amazing; people literally had no concept of just how full of stars the
dome really is.

I have met lifelong urban dwellers who have honestly professed to have
never seen more than a few dozen stars overhead.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

Ben C said:

Chalo said:

I'm looking forward to black diamond heat spreaders on kitchenware and
black diamond heat sinks on electronics.

What's a black diamond?

A diamond that is opaque and black in color. Most industrial diamonds
are black.

A black material would have much better emissivity than a water clear
one or an opaque white one. So although a black diamond heat sink
would have no higher heat conductivity than a clear one, it would be
better at shedding heat into its environment.

Chalo

"Werehatrack" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

In the aftermath of Hurricane Andrew, light pollution in southern Dade
County, Florida was drastically reduced, and many people there saw the
true night sky for the first time in their lives. The reaction was
amazing; people literally had no concept of just how full of stars the
dome really is.

I have met lifelong urban dwellers who have honestly professed to have
never seen more than a few dozen stars overhead.

They must not go to the Keys.