Old germanium transistors, A health risk?...

[none]

In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

I opened them and a white powder came out.
I hope it is not some berillium compound, but the best reason to have
something in there would be cooling, so that could make sense.
Normally I would think it would be a paste that dried out, but the can
is hermetically sealed.

What could that powder be?
(It can take decades to die from berillium poisoining so my
time is up.)

Groetjes Albert
--
This is the first day of the end of your life.
It may not kill you, but it does make your weaker.
If you can\'t beat them, too bad.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst

 

[Phil Hobbs]

On 2020-10-22 08:56, albert wrote:

In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

I opened them and a white powder came out.
I hope it is not some berillium compound, but the best reason to have
something in there would be cooling, so that could make sense.
Normally I would think it would be a paste that dried out, but the can
is hermetically sealed.

What could that powder be?
(It can take decades to die from berillium poisoining so my
time is up.)

How much of it, and what does it look like? Almost all white heatsink
grease is made from zinc oxide, as used on babies\' bottoms the world over.

The big beryllium scare was in the very early\'50s, so I wouldn\'t expect
beryllium oxide in heatsink grease from the transistor era. (I\'ve heard
anecdotal reports, but it\'s all FOAF stuff.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[none]

In article <3b20c028-b5e1-acc4-7b92-25f1c9f321b3@electrooptical.net>,
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-10-22 08:56, albert wrote:
In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

I opened them and a white powder came out.
I hope it is not some berillium compound, but the best reason to have
something in there would be cooling, so that could make sense.
Normally I would think it would be a paste that dried out, but the can
is hermetically sealed.

What could that powder be?
(It can take decades to die from berillium poisoining so my
time is up.)

How much of it, and what does it look like? Almost all white heatsink
grease is made from zinc oxide, as used on babies\' bottoms the world over.

About say 10% of the TO5 can.
What do you mean, what does white powder look like?

If it is zink oxide that is easy to check. ZnO turns yellow when heated.
I\'ll try and report back here, some time.

The big beryllium scare was in the very early\'50s, so I wouldn\'t expect
beryllium oxide in heatsink grease from the transistor era. (I\'ve heard
anecdotal reports, but it\'s all FOAF stuff.)
Remember that these were not commodity items, possibly military.

There seems to be substantial BeO in micro waves, so industrial use
of Be has not totally ceased.

Cheers

Phil Hobbs

Groetjes Albert
--
This is the first day of the end of your life.
It may not kill you, but it does make your weaker.
If you can\'t beat them, too bad.
albert@spe&ar&c.xs4all.nl &=n http://home.hccnet.nl/a.w.m.van.der.horst

 

[Steve Wilson]

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-10-22 08:56, albert wrote:
In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

I opened them and a white powder came out.
I hope it is not some berillium compound, but the best reason to have
something in there would be cooling, so that could make sense.
Normally I would think it would be a paste that dried out, but the
can is hermetically sealed.

What could that powder be?
(It can take decades to die from berillium poisoining so my time is
up.)

How much of it, and what does it look like? Almost all white heatsink
grease is made from zinc oxide, as used on babies\' bottoms the world
over.

Penaten. Zinc Oxide. 110 years of service. Good for bedsores from
hospital stays. Almost useless for anything else.

https://www.penaten.ca/

Heatsink grease often dries out. I notice this from salvaging CPUs from
older computers. IBM used to have huge heat dissipation problems on their
mainframes, but an extensive search doesn\'t reveal what they used for
their thermal grease.

I have switched to using mineral oil. It fills all the gaps and is less
likey to evaporate. So far it is working fine.

Cheers

Phil Hobbs

--
Science teaches us to trust. - sw

 

[Adrian Tuddenham]

albert <albert@cherry.(none)> wrote:

[...]

If it is zink oxide that is easy to check. ZnO turns yellow when heated.
I\'ll try and report back here, some time.

If you heat it and are still alive to report back, we shall know it
wasn\'t Beryllium

--
~ Adrian Tuddenham ~
(Remove the \".invalid\"s and add \".co.uk\" to reply)
www.poppyrecords.co.uk

 

[Jeff Liebermann]

On 22 Oct 2020 12:56:02 GMT, albert@cherry.(none) (albert) wrote:

In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

That would probably be a 2N107 or 2N404 in a TO-5 package. The cans
were made from brass, copper, tin, or aluminum depending on the
creativity of the manufacturer. Some were zinc plated.

>I opened them and a white powder came out.

How much white powder? The reason I ask is that I doubt that there
was enough plating on the transistor to produce very much white
powder. If you found a substantial amount of white powder, a better
guess would be zinc or lead oxides.

I hope it is not some berillium compound, but the best reason to have
something in there would be cooling, so that could make sense.

Beryllium produces a self protective oxide layer which will prevent
decomposition into a powder. The only way beryllium can produce a
powder is to grind it into a powder, which is VERY hazardous to one\'s
health. I used to deal with beryllium oxide heat spreaders in the
base of RF power transistors used in marine atmospheres and never saw
the beryllium decompose to a powder.

At the time (1970\'s), a problem we had with beryllium was the lack of
a cheap and easy indicator for the presence of beryllium oxide. So,
every white ceramic had to be considered a hazardous substance.

The addition to BeO to ceramics improves the head conduction about
15%. Unless you were dealing with ancient germanium power
transistors, there would be no need to use BeO in comparatively much
lower dissipation T0-5 packages. If you\'re looking for beryllium,
look for power devices.

There\'s no clue where your mystery boards have been. It is possible
to chemically attack beryllium with strong halide, sulfate, or nitrate
solutions. If that were the case, you would certainly have found
corrosive damage to some of the other components on the PCB\'s.

Normally I would think it would be a paste that dried out, but the can
is hermetically sealed.

That probably means that the PCB\'s were not attacked by outside
chemical agents. That leaves something inside the allegedly hermetic
seal. My guess(tm) would be a bad job of PCB cleaning after wave
soldering. The fluxes uses are corrosive and will eventually attack
the lead and zinc in the solder.

>What could that powder be?

Zinc and/or lead oxide.

(It can take decades to die from berillium poisoining so my
time is up.)

Remember, you have but one life to give to your profession.

>Groetjes Albert
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Gerhard Hoffmann]

Am 22.10.20 um 19:33 schrieb Adrian Tuddenham:

albert <albert@cherry.(none)> wrote:

[...]
If it is zink oxide that is easy to check. ZnO turns yellow when heated.
I\'ll try and report back here, some time.

If you heat it and are still alive to report back, we shall know it
wasn\'t Beryllium

It probably takes a very high temperature until gases develop.

But then, I found a box of 20 BFQ135 transistors this week when
sorting my parts inventory.

<
https://www.flickr.com/photos/137684711@N07/50517364401/in/album-72157662535945536/
>

A pinhead of the ceramic in the lung is pretty sure to give you
lung cancer. Well, it takes some time, maybe too long for me, but
the word \"expiration date\" gets a completely new meaning in the
context of lung cancer.

The transistors are nicely packed in a styro foam tablet, individually.

Cheers, Gerhard

 

[Phil Hobbs]

On 2020-10-22 12:26, albert wrote:

In article <3b20c028-b5e1-acc4-7b92-25f1c9f321b3@electrooptical.net>,
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2020-10-22 08:56, albert wrote:
In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

I opened them and a white powder came out.
I hope it is not some berillium compound, but the best reason to have
something in there would be cooling, so that could make sense.
Normally I would think it would be a paste that dried out, but the can
is hermetically sealed.

What could that powder be?
(It can take decades to die from berillium poisoining so my
time is up.)

How much of it, and what does it look like? Almost all white heatsink
grease is made from zinc oxide, as used on babies\' bottoms the world over.

About say 10% of the TO5 can.
What do you mean, what does white powder look like?

If it is zink oxide that is easy to check. ZnO turns yellow when heated.
I\'ll try and report back here, some time.


The big beryllium scare was in the very early\'50s, so I wouldn\'t expect
beryllium oxide in heatsink grease from the transistor era. (I\'ve heard
anecdotal reports, but it\'s all FOAF stuff.)
Remember that these were not commodity items, possibly military.

There seems to be substantial BeO in micro waves, so industrial use
of Be has not totally ceased.

Solid chunks of BeO are pretty safe as long as you don\'t put a grinder
on them--it\'s a hard refractory ceramic. It\'s just the powder that\'s
dangerous.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

On 2020-10-22 13:33, Adrian Tuddenham wrote:

albert <albert@cherry.(none)> wrote:

[...]
If it is zink oxide that is easy to check. ZnO turns yellow when heated.
I\'ll try and report back here, some time.

If you heat it and are still alive to report back, we shall know it
wasn\'t Beryllium

Beryllia melts at 2500C and boils at 3900C. You\'d really have to put it
to the torch to have anything to worry about.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

On 2020-10-22 12:31, Steve Wilson wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-10-22 08:56, albert wrote:
In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

I opened them and a white powder came out.
I hope it is not some berillium compound, but the best reason to have
something in there would be cooling, so that could make sense.
Normally I would think it would be a paste that dried out, but the
can is hermetically sealed.

What could that powder be?
(It can take decades to die from berillium poisoining so my time is
up.)

How much of it, and what does it look like? Almost all white heatsink
grease is made from zinc oxide, as used on babies\' bottoms the world
over.

Penaten. Zinc Oxide. 110 years of service. Good for bedsores from
hospital stays. Almost useless for anything else.

You\'re obviously not a dad. Zinc oxide ointment (Desitin by
preference) fixes diaper rash right up.

https://www.penaten.ca/

Heatsink grease often dries out. I notice this from salvaging CPUs from
older computers. IBM used to have huge heat dissipation problems on their
mainframes, but an extensive search doesn\'t reveal what they used for
their thermal grease.

TCMs don\'t use grease. When I left IBM about a dozen years ago, they
were using some Shin Etsu paste with about 3 W/m/K conductivity.

I have switched to using mineral oil. It fills all the gaps and is less
likey to evaporate. So far it is working fine.

Polydimethylsiloxane (Dimethicone) is the liquid of choice. Non-toxic,
very low vapour pressure.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Joe Gwinn]

On 22 Oct 2020 12:56:02 GMT, albert@cherry.(none) (albert) wrote:

In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

I opened them and a white powder came out.
I hope it is not some berillium compound, but the best reason to have
something in there would be cooling, so that could make sense.
Normally I would think it would be a paste that dried out, but the can
is hermetically sealed.

What could that powder be?
(It can take decades to die from berillium poisoining so my
time is up.)

Is this powder that was inside the metal can of the Ge transistor?

If so, it\'s probably a dessicant.

It will not contain Be - too expensive, and not needed.

Joe Gwinn

 

[Steve Wilson]

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-10-22 12:31, Steve Wilson wrote:
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

How much of it, and what does it look like? Almost all white
heatsink grease is made from zinc oxide, as used on babies\' bottoms
the world over.

Penaten. Zinc Oxide. 110 years of service. Good for bedsores from
hospital stays. Almost useless for anything else.

You\'re obviously not a dad. Zinc oxide ointment (Desitin by
preference) fixes diaper rash right up.

Two kids. I included diaper rash as the primary useage.

https://www.penaten.ca/

Heatsink grease often dries out. I notice this from salvaging CPUs
from older computers. IBM used to have huge heat dissipation problems
on their mainframes, but an extensive search doesn\'t reveal what they
used for their thermal grease.

TCMs don\'t use grease. When I left IBM about a dozen years ago, they
were using some Shin Etsu paste with about 3 W/m/K conductivity.

Sorry. I thought grease and paste meant the same thing when applied to
heatsinks.

I have switched to using mineral oil. It fills all the gaps and is
less likey to evaporate. So far it is working fine.

Polydimethylsiloxane (Dimethicone) is the liquid of choice.
Non-toxic, very low vapour pressure.

How much better than mineral oil?

Where do you get it? Amazon has an ointment that is 20% Dimethicone plus
a bunch of other stuff not needed for heatsinks.

Cheers

Phil Hobbs

--
Science teaches us to trust. - sw

 

[Phil Hobbs]

On 2020-10-22 19:01, Steve Wilson wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-10-22 12:31, Steve Wilson wrote:
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

How much of it, and what does it look like? Almost all white
heatsink grease is made from zinc oxide, as used on babies\' bottoms
the world over.

Penaten. Zinc Oxide. 110 years of service. Good for bedsores from
hospital stays. Almost useless for anything else.

You\'re obviously not a dad. Zinc oxide ointment (Desitin by
preference) fixes diaper rash right up.

Two kids. I included diaper rash as the primary useage.

https://www.penaten.ca/

Heatsink grease often dries out. I notice this from salvaging CPUs
from older computers. IBM used to have huge heat dissipation problems
on their mainframes, but an extensive search doesn\'t reveal what they
used for their thermal grease.

TCMs don\'t use grease. When I left IBM about a dozen years ago, they
were using some Shin Etsu paste with about 3 W/m/K conductivity.

Sorry. I thought grease and paste meant the same thing when applied to
heatsinks.

TCMs initially used helium gas, then switched to oil. They never used
paste or grease.

I have switched to using mineral oil. It fills all the gaps and is
less likey to evaporate. So far it is working fine.

Polydimethylsiloxane (Dimethicone) is the liquid of choice.
Non-toxic, very low vapour pressure.

How much better than mineral oil?

Dunno exactly, but it varies by viscosity. The carbon or silicon
dominates the molecular weight, whereas the hydrogen dominates the van
der Waals forces, so for the same chain length I\'d expect the vapour
pressure to be much lower.

Where do you get it? Amazon has an ointment that is 20% Dimethicone plus
a bunch of other stuff not needed for heatsinks.

BITD I ordered it from Clearco--about $70 per gallon, if you need that
much.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Allison]

none albert wrote:

===================

In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

I opened them and a white powder came out.
I hope it is not some berillium compound, but the best reason to have
something in there would be cooling, so that could make sense.
Normally I would think it would be a paste that dried out, but the can
is hermetically sealed.

What could that powder be?

** Likely a harmless moisture absorber.

Some TO3 pak devices have the same or else coat the chip in white silicone - especially Sanken.

I suspect other makers seal TO3 paks in a nitrogen atmosphere.

..... Phil

 

[Ollie B]

On 22 Oct 2020 12:56:02 GMT, albert@cherry.(none) (albert) wrote:

In the 70\'s I bought some computer dump stuff, these were
boards with digital circuits with germanium transistors in
a metal housing, of size 2n2905.

That would probably be a 2N107 or 2N404 in a TO-5 package. The cans
were made from brass, copper, tin, or aluminum depending on the
creativity of the manufacturer. Some were zinc plated.

I opened them and a white powder came out.

How much white powder? The reason I ask is that I doubt that there
was enough plating on the transistor to produce very much white
powder. If you found a substantial amount of white powder, a better
guess would be zinc or lead oxides.

Perhaps it is coke, transistor smugglers.


---
Ollie B

 

[Tauno Voipio]

On 22.10.20 21.44, Gerhard Hoffmann wrote:

Am 22.10.20 um 19:33 schrieb Adrian Tuddenham:
albert <albert@cherry.(none)> wrote:

[...]
If it is zink oxide that is easy to check. ZnO turns yellow when heated.
I\'ll try and report back here, some time.

If you heat it and are still alive to report back, we shall know it
wasn\'t Beryllium

It probably takes a very high temperature until gases develop.

But then, I found a box of 20 BFQ135 transistors this week when
sorting my parts inventory.


https://www.flickr.com/photos/137684711@N07/50517364401/in/album-72157662535945536/
   

A pinhead of the ceramic in the lung is pretty sure to give you
lung cancer. Well, it takes some time, maybe too long for me, but
the word \"expiration date\" gets a completely new meaning in the
context of lung cancer.

The transistors are nicely packed in a styro foam tablet, individually.

Cheers, Gerhard

The beryllia is well hidden inside, it is between the chip and
the mounting stud. The ceramic seen outside is alumina.

--

-TV

 

[Steve Wilson]

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-10-22 19:01, Steve Wilson wrote:

I have switched to using mineral oil. It fills all the gaps and is
less likey to evaporate. So far it is working fine.

Polydimethylsiloxane (Dimethicone) is the liquid of choice.
Non-toxic, very low vapour pressure.

How much better than mineral oil?

Dunno exactly, but it varies by viscosity. The carbon or silicon
dominates the molecular weight, whereas the hydrogen dominates the van
der Waals forces, so for the same chain length I\'d expect the vapour
pressure to be much lower.

Where do you get it? Amazon has an ointment that is 20% Dimethicone
plus a bunch of other stuff not needed for heatsinks.

BITD I ordered it from Clearco--about $70 per gallon, if you need that
much.

Cheers

Phil Hobbs

Mineral oil is very similar to Dimethicone.

Thermal conductivity (W/mK):

Air : 0.024
Dimethicone : 0.15
Mineral Oil : 0.136

Problems with thermal paste: poor repeatability, non repeatable
distribution, poor spreading, air gaps, dries out, insulating if too
thick.

Videos:

Do You Even NEED Thermal Paste? Arctic MX-4 Vs Toothpaste Vs Mayonnaise
Vs Vegemite - compares bare metal against various organic substances,
recommends mineral oil. <https://www.youtube.com/watch?v=D-pr4cf70qY>

How Thermal Compound Spreads
- uses glass plate to show distribution of thermal paste
<https://www.youtube.com/watch?v=EyXLu1Ms-q4>

How To Apply CPU Thermal Paste Methods - Compare and Benchmark
- uses Thermal Compound Arctic MX-4 and glass plate to measure
different spreading methods.
Temperature ranges from 87C to 82C.
<https://www.youtube.com/watch?v=LHOBRvXYqEg>

Saying Goodbye to Thermal Paste? Carbonaut Tested
- thermal paste dries out
<https://www.youtube.com/watch?v=tuxEsd-Fpwk>

Homemade solutions to replace CPU thermal paste
<https://www.powerelectronicsnews.com/homemade-solutions-to-replace-cpu-t
hermal-paste/>

I have removed the CPU\'s from three computers that used mineral oil for
over a year. There was complete uniformity in the distribution (it
covered the entire surface of the CPU), and no evidence of evaporation.

--
Science teaches us to trust. - sw

 

[server]

On Friday, 23 October 2020 18:35:30 UTC+1, Steve Wilson wrote:

Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-10-22 19:01, Steve Wilson wrote:

I have switched to using mineral oil. It fills all the gaps and is
less likey to evaporate. So far it is working fine.

Polydimethylsiloxane (Dimethicone) is the liquid of choice.
Non-toxic, very low vapour pressure.

How much better than mineral oil?

Dunno exactly, but it varies by viscosity. The carbon or silicon
dominates the molecular weight, whereas the hydrogen dominates the van
der Waals forces, so for the same chain length I\'d expect the vapour
pressure to be much lower.

Where do you get it? Amazon has an ointment that is 20% Dimethicone
plus a bunch of other stuff not needed for heatsinks.

BITD I ordered it from Clearco--about $70 per gallon, if you need that
much.

Cheers

Phil Hobbs

Mineral oil is very similar to Dimethicone.

Thermal conductivity (W/mK):

Air : 0.024
Dimethicone : 0.15
Mineral Oil : 0.136

Problems with thermal paste: poor repeatability, non repeatable
distribution, poor spreading, air gaps, dries out, insulating if too
thick.

Videos:

Do You Even NEED Thermal Paste? Arctic MX-4 Vs Toothpaste Vs Mayonnaise
Vs Vegemite - compares bare metal against various organic substances,
recommends mineral oil. <https://www.youtube.com/watch?v=D-pr4cf70qY

How Thermal Compound Spreads
- uses glass plate to show distribution of thermal paste
https://www.youtube.com/watch?v=EyXLu1Ms-q4

How To Apply CPU Thermal Paste Methods - Compare and Benchmark
- uses Thermal Compound Arctic MX-4 and glass plate to measure
different spreading methods.
Temperature ranges from 87C to 82C.
https://www.youtube.com/watch?v=LHOBRvXYqEg

Saying Goodbye to Thermal Paste? Carbonaut Tested
- thermal paste dries out
https://www.youtube.com/watch?v=tuxEsd-Fpwk

Homemade solutions to replace CPU thermal paste
https://www.powerelectronicsnews.com/homemade-solutions-to-replace-cpu-t
hermal-paste/

I have removed the CPU\'s from three computers that used mineral oil for
over a year. There was complete uniformity in the distribution (it
covered the entire surface of the CPU), and no evidence of evaporation.

In case its of any interest, MX4 is a blend of diamond powder, alumina
and silicone oil.

John

 

[Piotr Wyderski]

albert wrote:

There seems to be substantial BeO in micro waves, so industrial use
of Be has not totally ceased.

Is it really BeO, or just pink alumina ceramics?

Best regards, Piotr

 

[Steve Wilson]

jrwalliker@gmail.com wrote:

In case its of any interest, MX4 is a blend of diamond powder, alumina
and silicone oil.

John

8.5 W/mK

ARCTIC MX-4 : 73.2C
Scythe Thermal Elixer : 73.9C
Prolimatech PK-1 : 73.6C
Coolink Chillaramic : 74C
Gelid GC-2 : 74.2C
Noctua NT-H1 : 74.3C
Coolaboratory Liquid Ultra : 76.4C
EKL Alpenföhn Schneekanone : 76.9C
Thermalright Chill Factor ll : 77.1C
Akasa AK-455 : 78.3C

<https://www.arctic.ac/media/52/f1/a2/1585035312/spec_sheet_MX-4_181210
_r8a_EN.pdf>

Looks like any of them would work. Of course, you still have all the
problems with applying a paste. Mineral oil eliminates them.

--
Science teaches us to trust. - sw