Empathy List Archives

AK

Attila Kinali

Fri, Oct 30, 2020 9:49 PM

Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume.

So why do people choose copper instead of steel?

		Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

Moin, I have been looking at heat capacities of different materials lately. One thing that struk me odd is, that the volumetric heat capacity of copper, which is the thing that most people use when building something that needs to have high heat capacity to get stable temperature, has only a volumetric heat capacity of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has a volumetric heat capacity of 3.53 J/(cm^3·K) and steel even 3.75 J/(cm^3·K). In an OCXO, which is generally size limited, getting the most heat capacity in the limited volume would be the main goal, wouldn't it? Also optimizing for price would be a major thing. I can understand that iron is probably not the right choice due to its tendency to oxidize. But using a soft (annealed) steel would be easy to machine, cheaper per piece and give almost 10% higher heat capacity in the same volume. So why do people choose copper instead of steel? Attila Kinali PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K) at 25°C. We should fill OCXOs with water! :-D -- <JaberWorky> The bad part of Zurich is where the degenerates throw DARK chocolate at you.

BK

Bob kb8tq

Fri, Oct 30, 2020 9:58 PM

Hi

Simple answer: conductivity. You don’t get much heat capacity either way.

Bob

On Oct 30, 2020, at 5:49 PM, Attila Kinali attila@kinali.ch wrote:

Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume.

So why do people choose copper instead of steel?

		Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

time-nuts mailing list -- time-nuts@lists.febo.com
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and follow the instructions there.

Hi Simple answer: conductivity. You don’t get much heat capacity either way. Bob > On Oct 30, 2020, at 5:49 PM, Attila Kinali <attila@kinali.ch> wrote: > > Moin, > > I have been looking at heat capacities of different materials > lately. One thing that struk me odd is, that the volumetric > heat capacity of copper, which is the thing that most people > use when building something that needs to have high heat capacity > to get stable temperature, has only a volumetric heat capacity > of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has > a volumetric heat capacity of 3.53 J/(cm^3·K) and steel > even 3.75 J/(cm^3·K). > > In an OCXO, which is generally size limited, getting the most > heat capacity in the limited volume would be the main goal, > wouldn't it? Also optimizing for price would be a major thing. > I can understand that iron is probably not the right choice > due to its tendency to oxidize. But using a soft (annealed) steel > would be easy to machine, cheaper per piece and give almost 10% > higher heat capacity in the same volume. > > So why do people choose copper instead of steel? > > > Attila Kinali > > PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K) > at 25°C. We should fill OCXOs with water! :-D > > -- > <JaberWorky> The bad part of Zurich is where the degenerates > throw DARK chocolate at you. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

LA

Luiz Alberto Saba

Fri, Oct 30, 2020 10:06 PM

If my memory serves me, copper has the better conductivity of all the periodic table...

Enviado do meu iPhone

Em 30 de out. de 2020, à(s) 18:56, Attila Kinali attila@kinali.ch escreveu:

Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume.

So why do people choose copper instead of steel?

        Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

If my memory serves me, copper has the better conductivity of all the periodic table... Enviado do meu iPhone > Em 30 de out. de 2020, à(s) 18:56, Attila Kinali <attila@kinali.ch> escreveu: > > Moin, > > I have been looking at heat capacities of different materials > lately. One thing that struk me odd is, that the volumetric > heat capacity of copper, which is the thing that most people > use when building something that needs to have high heat capacity > to get stable temperature, has only a volumetric heat capacity > of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has > a volumetric heat capacity of 3.53 J/(cm^3·K) and steel > even 3.75 J/(cm^3·K). > > In an OCXO, which is generally size limited, getting the most > heat capacity in the limited volume would be the main goal, > wouldn't it? Also optimizing for price would be a major thing. > I can understand that iron is probably not the right choice > due to its tendency to oxidize. But using a soft (annealed) steel > would be easy to machine, cheaper per piece and give almost 10% > higher heat capacity in the same volume. > > So why do people choose copper instead of steel? > > > Attila Kinali > > PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K) > at 25°C. We should fill OCXOs with water! :-D > > -- > <JaberWorky> The bad part of Zurich is where the degenerates > throw DARK chocolate at you. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

LA

Luiz Alberto Saba

Fri, Oct 30, 2020 10:13 PM

My bad... copper is the second, losing only to silver, as a thermal conductor.

Enviado do meu iPhone

Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba las@intercat.com.br escreveu:

If my memory serves me, copper has the better conductivity of all the periodic table...

Enviado do meu iPhone

Em 30 de out. de 2020, à(s) 18:56, Attila Kinali attila@kinali.ch escreveu:

Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume.

So why do people choose copper instead of steel?

       Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

My bad... copper is the second, losing only to silver, as a thermal conductor. Enviado do meu iPhone > Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba <las@intercat.com.br> escreveu: > > If my memory serves me, copper has the better conductivity of all the periodic table... > > Enviado do meu iPhone > >> Em 30 de out. de 2020, à(s) 18:56, Attila Kinali <attila@kinali.ch> escreveu: >> >> Moin, >> >> I have been looking at heat capacities of different materials >> lately. One thing that struk me odd is, that the volumetric >> heat capacity of copper, which is the thing that most people >> use when building something that needs to have high heat capacity >> to get stable temperature, has only a volumetric heat capacity >> of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has >> a volumetric heat capacity of 3.53 J/(cm^3·K) and steel >> even 3.75 J/(cm^3·K). >> >> In an OCXO, which is generally size limited, getting the most >> heat capacity in the limited volume would be the main goal, >> wouldn't it? Also optimizing for price would be a major thing. >> I can understand that iron is probably not the right choice >> due to its tendency to oxidize. But using a soft (annealed) steel >> would be easy to machine, cheaper per piece and give almost 10% >> higher heat capacity in the same volume. >> >> So why do people choose copper instead of steel? >> >> >> Attila Kinali >> >> PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K) >> at 25°C. We should fill OCXOs with water! :-D >> >> -- >> <JaberWorky> The bad part of Zurich is where the degenerates >> throw DARK chocolate at you. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there.

AK

Attila Kinali

Fri, Oct 30, 2020 10:23 PM

On Fri, 30 Oct 2020 17:58:24 -0400
Bob kb8tq kb8tq@n1k.org wrote:

Simple answer: conductivity. You don’t get much heat capacity either way.

Ah.. so it is more important to have less temperature gradients
than having high capacity?

		Attila Kinali

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

On Fri, 30 Oct 2020 17:58:24 -0400 Bob kb8tq <kb8tq@n1k.org> wrote: > Simple answer: conductivity. You don’t get much heat capacity either way. Ah.. so it is more important to have less temperature gradients than having high capacity? Attila Kinali -- <JaberWorky> The bad part of Zurich is where the degenerates throw DARK chocolate at you.

R(

Richard (Rick) Karlquist

Fri, Oct 30, 2020 10:24 PM

Yes, we want conductivity, and not heat capacity.

On 10/30/2020 3:06 PM, Luiz Alberto Saba wrote:

If my memory serves me, copper has the better conductivity of all the periodic table...

Actually, carbon is at the top of the list.
Then silver, then copper.

Rick N6RK

Enviado do meu iPhone

Em 30 de out. de 2020, à(s) 18:56, Attila Kinali attila@kinali.ch escreveu:

Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume.

So why do people choose copper instead of steel?

         Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
and follow the instructions there.

Yes, we want conductivity, and not heat capacity. On 10/30/2020 3:06 PM, Luiz Alberto Saba wrote: > If my memory serves me, copper has the better conductivity of all the periodic table... > Actually, carbon is at the top of the list. Then silver, then copper. Rick N6RK > Enviado do meu iPhone > >> Em 30 de out. de 2020, à(s) 18:56, Attila Kinali <attila@kinali.ch> escreveu: >> >> Moin, >> >> I have been looking at heat capacities of different materials >> lately. One thing that struk me odd is, that the volumetric >> heat capacity of copper, which is the thing that most people >> use when building something that needs to have high heat capacity >> to get stable temperature, has only a volumetric heat capacity >> of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has >> a volumetric heat capacity of 3.53 J/(cm^3·K) and steel >> even 3.75 J/(cm^3·K). >> >> In an OCXO, which is generally size limited, getting the most >> heat capacity in the limited volume would be the main goal, >> wouldn't it? Also optimizing for price would be a major thing. >> I can understand that iron is probably not the right choice >> due to its tendency to oxidize. But using a soft (annealed) steel >> would be easy to machine, cheaper per piece and give almost 10% >> higher heat capacity in the same volume. >> >> So why do people choose copper instead of steel? >> >> >> Attila Kinali >> >> PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K) >> at 25°C. We should fill OCXOs with water! :-D >> >> -- >> <JaberWorky> The bad part of Zurich is where the degenerates >> throw DARK chocolate at you. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

AT

Andy Talbot

Fri, Oct 30, 2020 10:25 PM

Actually, diamond has five times better thermal conductivity than silver,
so is the most conductive element, although graphene is suspected to be
better still.

Andy
www.g4jnt.com

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On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba las@intercat.com.br wrote:

My bad... copper is the second, losing only to silver, as a thermal
conductor.

Enviado do meu iPhone

Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba <

las@intercat.com.br> escreveu:

If my memory serves me, copper has the better conductivity of all the

periodic table...

Enviado do meu iPhone

Em 30 de out. de 2020, à(s) 18:56, Attila Kinali attila@kinali.ch

escreveu:

Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume.

So why do people choose copper instead of steel?

       Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to

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and follow the instructions there.

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and follow the instructions there.

Actually, diamond has five times better thermal conductivity than silver, so is the most conductive element, although graphene is suspected to be better still. Andy www.g4jnt.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> Virus-free. www.avg.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba <las@intercat.com.br> wrote: > My bad... copper is the second, losing only to silver, as a thermal > conductor. > > Enviado do meu iPhone > > > Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba < > las@intercat.com.br> escreveu: > > > > If my memory serves me, copper has the better conductivity of all the > periodic table... > > > > Enviado do meu iPhone > > > >> Em 30 de out. de 2020, à(s) 18:56, Attila Kinali <attila@kinali.ch> > escreveu: > >> > >> Moin, > >> > >> I have been looking at heat capacities of different materials > >> lately. One thing that struk me odd is, that the volumetric > >> heat capacity of copper, which is the thing that most people > >> use when building something that needs to have high heat capacity > >> to get stable temperature, has only a volumetric heat capacity > >> of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has > >> a volumetric heat capacity of 3.53 J/(cm^3·K) and steel > >> even 3.75 J/(cm^3·K). > >> > >> In an OCXO, which is generally size limited, getting the most > >> heat capacity in the limited volume would be the main goal, > >> wouldn't it? Also optimizing for price would be a major thing. > >> I can understand that iron is probably not the right choice > >> due to its tendency to oxidize. But using a soft (annealed) steel > >> would be easy to machine, cheaper per piece and give almost 10% > >> higher heat capacity in the same volume. > >> > >> So why do people choose copper instead of steel? > >> > >> > >> Attila Kinali > >> > >> PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K) > >> at 25°C. We should fill OCXOs with water! :-D > >> > >> -- > >> <JaberWorky> The bad part of Zurich is where the degenerates > >> throw DARK chocolate at you. > >> > >> _______________________________________________ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

DD

Dave Daniel

Fri, Oct 30, 2020 11:27 PM

Heat capacity is essentially a measure of how much heat a material can hold (to a first approximation). Thermal conductivity is a measure of how well a material moves heat between two different temperatures mechanically connected to the material. When using a material as a heat sink, one wants to transfer the heat from the device being cooled to the (presumably cooler) ambient environment as quickly as possible, so thermal conductivity is more important than heat capacity for that application.

Note that a “heat sink” may also be used to warm up a cold material (e.g., reverse heat flow). A trivial example of this is that if you want to quickly defrost a piece of food, lay it on a good thermally conductive surface such as a large aluminum or copper pan or tray. The food will defrost quickly because one is moving heat from the ambient environment into the food more quickly than if the food is just sitting on one’s countertop.

DaveD

On Oct 30, 2020, at 18:23, Attila Kinali attila@kinali.ch wrote:

On Fri, 30 Oct 2020 17:58:24 -0400
Bob kb8tq kb8tq@n1k.org wrote:

Simple answer: conductivity. You don’t get much heat capacity either way.

Ah.. so it is more important to have less temperature gradients
than having high capacity?

        Attila Kinali

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

time-nuts mailing list -- time-nuts@lists.febo.com
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Heat capacity is essentially a measure of how much heat a material can hold (to a first approximation). Thermal conductivity is a measure of how well a material moves heat between two different temperatures mechanically connected to the material. When using a material as a heat sink, one wants to transfer the heat from the device being cooled to the (presumably cooler) ambient environment as quickly as possible, so thermal conductivity is more important than heat capacity for that application. Note that a “heat sink” may also be used to warm up a cold material (e.g., reverse heat flow). A trivial example of this is that if you want to quickly defrost a piece of food, lay it on a good thermally conductive surface such as a large aluminum or copper pan or tray. The food will defrost quickly because one is moving heat from the ambient environment into the food more quickly than if the food is just sitting on one’s countertop. DaveD > On Oct 30, 2020, at 18:23, Attila Kinali <attila@kinali.ch> wrote: > > On Fri, 30 Oct 2020 17:58:24 -0400 > Bob kb8tq <kb8tq@n1k.org> wrote: > >> Simple answer: conductivity. You don’t get much heat capacity either way. > > Ah.. so it is more important to have less temperature gradients > than having high capacity? > > Attila Kinali > > -- > <JaberWorky> The bad part of Zurich is where the degenerates > throw DARK chocolate at you. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

R(

Richard (Rick) Karlquist

Fri, Oct 30, 2020 11:48 PM

Diamond, graphite and graphene are all forms of the
element carbon. They all can have more conductivity
than silver.

Rick N6RK

On 10/30/2020 3:25 PM, Andy Talbot wrote:

Actually, diamond has five times better thermal conductivity than silver,
so is the most conductive element, although graphene is suspected to be
better still.

Andy
www.g4jnt.com

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On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba las@intercat.com.br wrote:

My bad... copper is the second, losing only to silver, as a thermal
conductor.

Enviado do meu iPhone

Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba <

las@intercat.com.br> escreveu:

If my memory serves me, copper has the better conductivity of all the

periodic table...

Enviado do meu iPhone

Em 30 de out. de 2020, à(s) 18:56, Attila Kinali attila@kinali.ch

escreveu:

Moin,

I have been looking at heat capacities of different materials
lately. One thing that struk me odd is, that the volumetric
heat capacity of copper, which is the thing that most people
use when building something that needs to have high heat capacity
to get stable temperature, has only a volumetric heat capacity
of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has
a volumetric heat capacity of 3.53 J/(cm^3·K) and steel
even 3.75 J/(cm^3·K).

In an OCXO, which is generally size limited, getting the most
heat capacity in the limited volume would be the main goal,
wouldn't it? Also optimizing for price would be a major thing.
I can understand that iron is probably not the right choice
due to its tendency to oxidize. But using a soft (annealed) steel
would be easy to machine, cheaper per piece and give almost 10%
higher heat capacity in the same volume.

So why do people choose copper instead of steel?

        Attila Kinali

PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K)
at 25°C. We should fill OCXOs with water! :-D

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe, go to

http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com

and follow the instructions there.

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Diamond, graphite and graphene are all forms of the element carbon. They all can have more conductivity than silver. Rick N6RK On 10/30/2020 3:25 PM, Andy Talbot wrote: > Actually, diamond has five times better thermal conductivity than silver, > so is the most conductive element, although graphene is suspected to be > better still. > > > Andy > www.g4jnt.com > > > > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > Virus-free. > www.avg.com > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail> > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > > On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba <las@intercat.com.br> wrote: > >> My bad... copper is the second, losing only to silver, as a thermal >> conductor. >> >> Enviado do meu iPhone >> >>> Em 30 de out. de 2020, à(s) 19:06, Luiz Alberto Saba < >> las@intercat.com.br> escreveu: >>> >>> If my memory serves me, copper has the better conductivity of all the >> periodic table... >>> >>> Enviado do meu iPhone >>> >>>> Em 30 de out. de 2020, à(s) 18:56, Attila Kinali <attila@kinali.ch> >> escreveu: >>>> >>>> Moin, >>>> >>>> I have been looking at heat capacities of different materials >>>> lately. One thing that struk me odd is, that the volumetric >>>> heat capacity of copper, which is the thing that most people >>>> use when building something that needs to have high heat capacity >>>> to get stable temperature, has only a volumetric heat capacity >>>> of 3.45 J/(cm^3·K). Meanwhile, the much cheaper iron has >>>> a volumetric heat capacity of 3.53 J/(cm^3·K) and steel >>>> even 3.75 J/(cm^3·K). >>>> >>>> In an OCXO, which is generally size limited, getting the most >>>> heat capacity in the limited volume would be the main goal, >>>> wouldn't it? Also optimizing for price would be a major thing. >>>> I can understand that iron is probably not the right choice >>>> due to its tendency to oxidize. But using a soft (annealed) steel >>>> would be easy to machine, cheaper per piece and give almost 10% >>>> higher heat capacity in the same volume. >>>> >>>> So why do people choose copper instead of steel? >>>> >>>> >>>> Attila Kinali >>>> >>>> PS: Fun fact: Water has a volumetric heat capacity of 4.18 J/(cm^3·K) >>>> at 25°C. We should fill OCXOs with water! :-D >>>> >>>> -- >>>> <JaberWorky> The bad part of Zurich is where the degenerates >>>> throw DARK chocolate at you. >>>> >>>> _______________________________________________ >>>> time-nuts mailing list -- time-nuts@lists.febo.com >>>> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>>> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

DD

Dr. David Kirkby

Fri, Oct 30, 2020 11:49 PM

On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba las@intercat.com.br wrote:

My bad... copper is the second, losing only to silver, as a thermal
conductor.

I think you are mistaken. Copper is second to silver for electrical
conductivity, but I doubt that is so for thermal conductivity. I think
diamond, which is a form of carbon, is the best thermal conductor, and
around 5x better than copper.

Dave

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@kirkbymicrowave.co.uk
https://www.kirkbymicrowave.co.uk/
Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba <las@intercat.com.br> wrote: > My bad... copper is the second, losing only to silver, as a thermal > conductor. > I think you are mistaken. Copper is second to silver for *electrical* conductivity, but I doubt that is so for thermal conductivity. I think diamond, which is a form of carbon, is the best thermal conductor, and around 5x better than copper. Dave -- Dr. David Kirkby, Kirkby Microwave Ltd, drkirkby@kirkbymicrowave.co.uk https://www.kirkbymicrowave.co.uk/ Telephone 01621-680100./ +44 1621 680100 Registered in England & Wales, company number 08914892. Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom

BK

Bob kb8tq

Sat, Oct 31, 2020 12:05 AM

Hi

Gradients are a really big deal in an OCXO. Thermal mass works against
you if you are after quick warmup ….

Bob

On Oct 30, 2020, at 6:23 PM, Attila Kinali attila@kinali.ch wrote:

On Fri, 30 Oct 2020 17:58:24 -0400
Bob kb8tq kb8tq@n1k.org wrote:

Simple answer: conductivity. You don’t get much heat capacity either way.

Ah.. so it is more important to have less temperature gradients
than having high capacity?

		Attila Kinali

--
<JaberWorky> The bad part of Zurich is where the degenerates
throw DARK chocolate at you.

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Hi Gradients are a really big deal in an OCXO. Thermal mass works against you if you are after quick warmup …. Bob > On Oct 30, 2020, at 6:23 PM, Attila Kinali <attila@kinali.ch> wrote: > > On Fri, 30 Oct 2020 17:58:24 -0400 > Bob kb8tq <kb8tq@n1k.org> wrote: > >> Simple answer: conductivity. You don’t get much heat capacity either way. > > Ah.. so it is more important to have less temperature gradients > than having high capacity? > > Attila Kinali > > -- > <JaberWorky> The bad part of Zurich is where the degenerates > throw DARK chocolate at you. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

R(

Richard (Rick) Karlquist

Sat, Oct 31, 2020 2:23 AM

On 10/30/2020 5:05 PM, Bob kb8tq wrote:

Hi

Gradients are a really big deal in an OCXO. Thermal mass works against
you if you are after quick warmup ….

Bob

I'll take this opportunity to plug my 1997 FCS paper:
"The Theory of Zero Gradient Ovens" explaining how
we got thermal gain over 1 million. You better
believe gradients are a really big deal.

Rick N6RK

On 10/30/2020 5:05 PM, Bob kb8tq wrote: > Hi > > Gradients are a really big deal in an OCXO. Thermal mass works against > you if you are after quick warmup …. > > Bob > I'll take this opportunity to plug my 1997 FCS paper: "The Theory of Zero Gradient Ovens" explaining how we got thermal gain over 1 million. You better believe gradients are a really big deal. Rick N6RK

BG

Bruce Griffiths

Sat, Oct 31, 2020 2:50 AM

Not true
The Wiedemann-Franz gives the ratio of the thermal conductivity to electrical conductivity of a metal:
( pi^2 / 3 ) * ( (k/e)^2 ) * T

Bruce

On 31 October 2020 at 12:49 "Dr. David Kirkby" drkirkby@kirkbymicrowave.co.uk wrote:

On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba las@intercat.com.br wrote:

My bad... copper is the second, losing only to silver, as a thermal
conductor.

I think you are mistaken. Copper is second to silver for electrical
conductivity, but I doubt that is so for thermal conductivity. I think
diamond, which is a form of carbon, is the best thermal conductor, and
around 5x better than copper.

Dave

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@kirkbymicrowave.co.uk
https://www.kirkbymicrowave.co.uk/
Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

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Not true The Wiedemann-Franz gives the ratio of the thermal conductivity to electrical conductivity of a metal: ( pi^2 / 3 ) * ( (k/e)^2 ) * T Bruce > On 31 October 2020 at 12:49 "Dr. David Kirkby" <drkirkby@kirkbymicrowave.co.uk> wrote: > > > On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba <las@intercat.com.br> wrote: > > > My bad... copper is the second, losing only to silver, as a thermal > > conductor. > > > > I think you are mistaken. Copper is second to silver for *electrical* > conductivity, but I doubt that is so for thermal conductivity. I think > diamond, which is a form of carbon, is the best thermal conductor, and > around 5x better than copper. > > Dave > > -- > Dr. David Kirkby, > Kirkby Microwave Ltd, > drkirkby@kirkbymicrowave.co.uk > https://www.kirkbymicrowave.co.uk/ > Telephone 01621-680100./ +44 1621 680100 > > Registered in England & Wales, company number 08914892. > Registered office: > Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United > Kingdom > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

TP

Tobias Pluess

Sat, Oct 31, 2020 11:47 AM

Also an interesting material when high thermal conductivity is considered
is boron nitride. It is around five times better than copper, comparable
to diamond and can be sintered to a ceramic material.
Of course the Wiedemann-Franz-Lorenz law doesn't apply here as it is a very
good electrical insulator.
A boron nitride OCXO would indeed be interesting! :-)

I use certain kinds of boron nitride at work to increase the the thermal
conductivity of some plastic materials.

Tobias

On Sat., 31 Oct. 2020, 03:57 Bruce Griffiths, bruce.griffiths@xtra.co.nz
wrote:

Not true
The Wiedemann-Franz gives the ratio of the thermal conductivity to
electrical conductivity of a metal:
( pi^2 / 3 ) * ( (k/e)^2 ) * T

Bruce

On 31 October 2020 at 12:49 "Dr. David Kirkby" <

drkirkby@kirkbymicrowave.co.uk> wrote:

On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba las@intercat.com.br

wrote:

My bad... copper is the second, losing only to silver, as a thermal
conductor.

I think you are mistaken. Copper is second to silver for electrical
conductivity, but I doubt that is so for thermal conductivity. I think
diamond, which is a form of carbon, is the best thermal conductor, and
around 5x better than copper.

Dave

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@kirkbymicrowave.co.uk
https://www.kirkbymicrowave.co.uk/
Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT,

United

Kingdom

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Also an interesting material when high thermal conductivity is considered is boron nitride. It is around five times better than copper, comparable to diamond and can be sintered to a ceramic material. Of course the Wiedemann-Franz-Lorenz law doesn't apply here as it is a very good electrical insulator. A boron nitride OCXO would indeed be interesting! :-) I use certain kinds of boron nitride at work to increase the the thermal conductivity of some plastic materials. Tobias On Sat., 31 Oct. 2020, 03:57 Bruce Griffiths, <bruce.griffiths@xtra.co.nz> wrote: > Not true > The Wiedemann-Franz gives the ratio of the thermal conductivity to > electrical conductivity of a metal: > ( pi^2 / 3 ) * ( (k/e)^2 ) * T > > Bruce > > On 31 October 2020 at 12:49 "Dr. David Kirkby" < > drkirkby@kirkbymicrowave.co.uk> wrote: > > > > > > On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba <las@intercat.com.br> > wrote: > > > > > My bad... copper is the second, losing only to silver, as a thermal > > > conductor. > > > > > > > I think you are mistaken. Copper is second to silver for *electrical* > > conductivity, but I doubt that is so for thermal conductivity. I think > > diamond, which is a form of carbon, is the best thermal conductor, and > > around 5x better than copper. > > > > Dave > > > > -- > > Dr. David Kirkby, > > Kirkby Microwave Ltd, > > drkirkby@kirkbymicrowave.co.uk > > https://www.kirkbymicrowave.co.uk/ > > Telephone 01621-680100./ +44 1621 680100 > > > > Registered in England & Wales, company number 08914892. > > Registered office: > > Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, > United > > Kingdom > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

LA

Luiz Alberto Saba

Sat, Oct 31, 2020 12:10 PM

Interesting list

https://thermtest.com/thermal-resources/top-10-thermally-conductive-materials

Enviado do meu iPhone

Em 30 de out. de 2020, à(s) 23:57, Bruce Griffiths bruce.griffiths@xtra.co.nz escreveu:

Not true
The Wiedemann-Franz gives the ratio of the thermal conductivity to electrical conductivity of a metal:
( pi^2 / 3 ) * ( (k/e)^2 ) * T

Bruce

On 31 October 2020 at 12:49 "Dr. David Kirkby" drkirkby@kirkbymicrowave.co.uk wrote:

On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba las@intercat.com.br wrote:

My bad... copper is the second, losing only to silver, as a thermal
conductor.

I think you are mistaken. Copper is second to silver for electrical
conductivity, but I doubt that is so for thermal conductivity. I think
diamond, which is a form of carbon, is the best thermal conductor, and
around 5x better than copper.

Dave

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@kirkbymicrowave.co.uk
https://www.kirkbymicrowave.co.uk/
Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

time-nuts mailing list -- time-nuts@lists.febo.com
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Interesting list https://thermtest.com/thermal-resources/top-10-thermally-conductive-materials Enviado do meu iPhone > Em 30 de out. de 2020, à(s) 23:57, Bruce Griffiths <bruce.griffiths@xtra.co.nz> escreveu: > > Not true > The Wiedemann-Franz gives the ratio of the thermal conductivity to electrical conductivity of a metal: > ( pi^2 / 3 ) * ( (k/e)^2 ) * T > > Bruce >> On 31 October 2020 at 12:49 "Dr. David Kirkby" <drkirkby@kirkbymicrowave.co.uk> wrote: >> >> >>> On Fri, 30 Oct 2020 at 22:17, Luiz Alberto Saba <las@intercat.com.br> wrote: >>> >>> My bad... copper is the second, losing only to silver, as a thermal >>> conductor. >>> >> >> I think you are mistaken. Copper is second to silver for *electrical* >> conductivity, but I doubt that is so for thermal conductivity. I think >> diamond, which is a form of carbon, is the best thermal conductor, and >> around 5x better than copper. >> >> Dave >> >> -- >> Dr. David Kirkby, >> Kirkby Microwave Ltd, >> drkirkby@kirkbymicrowave.co.uk >> https://www.kirkbymicrowave.co.uk/ >> Telephone 01621-680100./ +44 1621 680100 >> >> Registered in England & Wales, company number 08914892. >> Registered office: >> Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United >> Kingdom >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

BN

Bernd Neubig

Sun, Nov 1, 2020 10:20 AM

-----Tobias wrote-----

Also an interesting material when high thermal conductivity is considered

is boron nitride. It is around five times better than copper, comparable to
diamond and can be sintered to a ceramic material.

Of course the Wiedemann-Franz-Lorenz law doesn't apply here as it is a very

good electrical insulator.

A boron nitride OCXO would indeed be interesting! :-)

About 30 years ago, in my previous job as head of TeleQuarz oscillator
division (now Vectron->...Microchip), we had used AlN hybrid substrates
replacing the FR4 PCB in OCXO. We had built up a complete hybrid
manufacturing line for that. Aluminum Nitride has an extremely high thermal
conductivity while being an isolator. The thermal performance was excellent.
However it was nearly impossible to solder on it manually (e.g. to change
components for fine tuning purposes) because the solder literally was
freezing on the substrate and even a special soldering iron with temperature
regulation directly in thee tip (Metcal) was not able to deliver sufficient
heat fast enough. After a few years we stopped this line.

Have a nice Sunday.
Bernd

-----Tobias wrote----- >Also an interesting material when high thermal conductivity is considered is boron nitride. It is around five times better than copper, comparable to diamond and can be sintered to a ceramic material. >Of course the Wiedemann-Franz-Lorenz law doesn't apply here as it is a very good electrical insulator. >A boron nitride OCXO would indeed be interesting! :-) About 30 years ago, in my previous job as head of TeleQuarz oscillator division (now Vectron->...Microchip), we had used AlN hybrid substrates replacing the FR4 PCB in OCXO. We had built up a complete hybrid manufacturing line for that. Aluminum Nitride has an extremely high thermal conductivity while being an isolator. The thermal performance was excellent. However it was nearly impossible to solder on it manually (e.g. to change components for fine tuning purposes) because the solder literally was freezing on the substrate and even a special soldering iron with temperature regulation directly in thee tip (Metcal) was not able to deliver sufficient heat fast enough. After a few years we stopped this line. Have a nice Sunday. Bernd

BK

Bob kb8tq

Sun, Nov 1, 2020 1:33 PM

Hi

….. and of course, there was an OCXO that used a beryllium oxide substrate
in pretty much the same way (inner oven in a double oven). Same basic issues
and not exactly cost effective.

The alumina substrate lives on in a number of miniature oven designs.

Bob

On Nov 1, 2020, at 5:20 AM, Bernd Neubig BNeubig@t-online.de wrote:

-----Tobias wrote-----

Also an interesting material when high thermal conductivity is considered

is boron nitride. It is around five times better than copper, comparable to
diamond and can be sintered to a ceramic material.

Of course the Wiedemann-Franz-Lorenz law doesn't apply here as it is a very

good electrical insulator.

A boron nitride OCXO would indeed be interesting! :-)

About 30 years ago, in my previous job as head of TeleQuarz oscillator
division (now Vectron->...Microchip), we had used AlN hybrid substrates
replacing the FR4 PCB in OCXO. We had built up a complete hybrid
manufacturing line for that. Aluminum Nitride has an extremely high thermal
conductivity while being an isolator. The thermal performance was excellent.
However it was nearly impossible to solder on it manually (e.g. to change
components for fine tuning purposes) because the solder literally was
freezing on the substrate and even a special soldering iron with temperature
regulation directly in thee tip (Metcal) was not able to deliver sufficient
heat fast enough. After a few years we stopped this line.

Have a nice Sunday.
Bernd

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Hi ….. and of course, there was an OCXO that used a beryllium oxide substrate in pretty much the same way (inner oven in a double oven). Same basic issues and not exactly cost effective. The alumina substrate lives on in a number of miniature oven designs. Bob > On Nov 1, 2020, at 5:20 AM, Bernd Neubig <BNeubig@t-online.de> wrote: > > > > -----Tobias wrote----- >> Also an interesting material when high thermal conductivity is considered > is boron nitride. It is around five times better than copper, comparable to > diamond and can be sintered to a ceramic material. >> Of course the Wiedemann-Franz-Lorenz law doesn't apply here as it is a very > good electrical insulator. >> A boron nitride OCXO would indeed be interesting! :-) > > About 30 years ago, in my previous job as head of TeleQuarz oscillator > division (now Vectron->...Microchip), we had used AlN hybrid substrates > replacing the FR4 PCB in OCXO. We had built up a complete hybrid > manufacturing line for that. Aluminum Nitride has an extremely high thermal > conductivity while being an isolator. The thermal performance was excellent. > However it was nearly impossible to solder on it manually (e.g. to change > components for fine tuning purposes) because the solder literally was > freezing on the substrate and even a special soldering iron with temperature > regulation directly in thee tip (Metcal) was not able to deliver sufficient > heat fast enough. After a few years we stopped this line. > > Have a nice Sunday. > Bernd > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

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OCXO housings - Why copper and not iron/steel?