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

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OCXO housings - Why copper and not iron/steel?