Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default What is that whiteish stuff on bad batteries (ruins stuff)?

On Tuesday, August 18, 2015 at 4:35:13 PM UTC-7, Jeff Liebermann wrote:
On Tue, 18 Aug 2015 12:01:51 -0700 (PDT), whit3rd
wrote:

On Tuesday, August 18, 2015 at 8:20:56 AM UTC-7, Jeff Liebermann wrote:
On Mon, 17 Aug 2015 15:56:53 -0700 (PDT), wrote:

Battery and ground contact areas eg terminals, clamps, frame connection areas are coated with a thin film of [silicone grease]


suggested that he grease his sheet metal pieces before spot welding
... the grease exploded in the spot welder


Yes, grease is good, but not in the current flow.


There's formulations of grease that don't do that, of course; silicone takes high
temperature, and some greases are intended for electrical conduction in thin
films (they 'break down' at millivolts, and don't even get hot).
http://store.caig.com/s.nl/sc.2/category.185/.f
I've used this grease on rotating connections, at 40A it's just like
a solid wire connection.



Looks like aluminum dust, copper dust, graphite, and/or quartz(???).


Can't be, it's transparent. It's based on a semiconductive component, which is nonlinear:
insulating in bulk, but breaks down (in conductivity, not chemical nature) in
thin films under electrical stress. US Patent #4696832 has more info.

One your rotating joint connection, did you use brushes or a
commutator to make the connection? If so, the path of least
resistance is through these connections, not through the grease.


It was bronze rubbing on a steel element; the grease keeps the steel from oxidizing
while increasing the effective contact area.
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Default What is that whiteish stuff on bad batteries (ruins stuff)?

On Tue, 18 Aug 2015 16:58:50 -0700 (PDT), whit3rd
wrote:

On Tuesday, August 18, 2015 at 4:35:13 PM UTC-7, Jeff Liebermann wrote:
On Tue, 18 Aug 2015 12:01:51 -0700 (PDT), whit3rd
wrote:

On Tuesday, August 18, 2015 at 8:20:56 AM UTC-7, Jeff Liebermann wrote:
On Mon, 17 Aug 2015 15:56:53 -0700 (PDT), wrote:

Battery and ground contact areas eg terminals, clamps, frame connection areas are coated with a thin film of [silicone grease]

suggested that he grease his sheet metal pieces before spot welding
... the grease exploded in the spot welder


Yes, grease is good, but not in the current flow.


There's formulations of grease that don't do that, of course; silicone takes high
temperature, and some greases are intended for electrical conduction in thin
films (they 'break down' at millivolts, and don't even get hot).
http://store.caig.com/s.nl/sc.2/category.185/.f
I've used this grease on rotating connections, at 40A it's just like
a solid wire connection.


Looks like aluminum dust, copper dust, graphite, and/or quartz(???).


Can't be, it's transparent. It's based on a semiconductive component, which is nonlinear:
insulating in bulk, but breaks down (in conductivity, not chemical nature) in
thin films under electrical stress. US Patent #4696832 has more info.


Never heard of that stuff, but if it's as you describe, it should be
quite useful. How conductive, I don't know. The patent isn't very
helpful:
http://www.google.com/patents/US4696832
"The contact stabilization material comprises at least one
block polymer or co-polymer of polyoxypropylene together
with polyoxyethylene."
It then points to a French patent:
http://www.google.com/patents/EP0144399A1?cl=en
which has a better explanation. I'll RTFM over the weeken.

I got the Caig L260 and M260 info you linked came from:
http://store.caig.com/s.nl/sc.18/category.1049/.f
(Sorry I forgot to include the link. Kinda crazy today). Notice the
mention of metallic filler. Is Caig L260 and M260 the right grease or
should I be looking for something else?

One your rotating joint connection, did you use brushes or a
commutator to make the connection? If so, the path of least
resistance is through these connections, not through the grease.


It was bronze rubbing on a steel element; the grease keeps the steel from oxidizing
while increasing the effective contact area.


--
Jeff Liebermann

150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Default What is that whiteish stuff on bad batteries (ruins stuff)?

On Tuesday, August 18, 2015 at 7:02:20 PM UTC-7, Jeff Liebermann wrote:
On Tue, 18 Aug 2015 16:58:50 -0700 (PDT), whit3rd
wrote:


... some greases are intended for electrical conduction in thin
films (they 'break down' at millivolts, and don't even get hot).
http://store.caig.com/s.nl/sc.2/category.185/.f
I've used this grease on rotating connections, at 40A it's just like
a solid wire connection.


Looks like aluminum dust, copper dust, graphite, and/or quartz(???).


Can't be, it's transparent. It's based on a semiconductive component, which is nonlinear:
insulating in bulk, but breaks down (in conductivity, not chemical nature) in
thin films under electrical stress. US Patent #4696832 has more info.


Never heard of that stuff, but if it's as you describe, it should be
quite useful. How conductive, I don't know. The patent isn't very
helpful:
http://www.google.com/patents/US4696832


Yeah, there's a high information cost... and there's more boosterism than
chemical physics in the sales lit. As to 'how conductive', the L260 variant
that I used doesn't have conductive particles, so it only conducts in thin films,
like rubbing parts would have around contact points. Because it is nonlinear,
'conductivity' is undefined (and the rubbing of bumpy surfaces mean
the film thickness is likewise indefinite). Variants on this lubricant
are recommended for slide potentiometers, I see.

The admixture of conductive particles would make a grease conduct electricity,
but that would be unsafe in electrical panels (and the intended uses include busbars).
It would decalibrate potentiometers, too. Because metallic particles would
constitute dissimilar metals in my mechanism, I didn't want to use such a grease.
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Default What is that whiteish stuff on bad batteries (ruins stuff)?

On Wednesday, August 19, 2015 at 4:20:17 AM UTC-4, whit3rd wrote:
On Tuesday, August 18, 2015 at 7:02:20 PM UTC-7, Jeff Liebermann wrote:
On Tue, 18 Aug 2015 16:58:50 -0700 (PDT), whit3rd
wrote:


... some greases are intended for electrical conduction in thin
films (they 'break down' at millivolts, and don't even get hot).
http://store.caig.com/s.nl/sc.2/category.185/.f
I've used this grease on rotating connections, at 40A it's just like
a solid wire connection.


Looks like aluminum dust, copper dust, graphite, and/or quartz(???).


Can't be, it's transparent. It's based on a semiconductive component, which is nonlinear:
insulating in bulk, but breaks down (in conductivity, not chemical nature) in
thin films under electrical stress. US Patent #4696832 has more info.


Never heard of that stuff, but if it's as you describe, it should be
quite useful. How conductive, I don't know. The patent isn't very
helpful:
http://www.google.com/patents/US4696832


Yeah, there's a high information cost... and there's more boosterism than
chemical physics in the sales lit. As to 'how conductive', the L260 variant
that I used doesn't have conductive particles, so it only conducts in thin films,
like rubbing parts would have around contact points. Because it is nonlinear,
'conductivity' is undefined (and the rubbing of bumpy surfaces mean
the film thickness is likewise indefinite). Variants on this lubricant
are recommended for slide potentiometers, I see.

The admixture of conductive particles would make a grease conduct electricity,
but that would be unsafe in electrical panels (and the intended uses include busbars).
It would decalibrate potentiometers, too. Because metallic particles would
constitute dissimilar metals in my mechanism, I didn't want to use such a grease.


MMMMMMMMMMMMMM

use the artist's paintbrush not the zerkgun ....
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Default What is that whiteish stuff on bad batteries (ruins stuff)?

On Wed, 19 Aug 2015 01:20:09 -0700 (PDT), whit3rd
wrote:

Yeah, there's a high information cost... and there's more boosterism than
chemical physics in the sales lit. As to 'how conductive', the L260 variant
that I used doesn't have conductive particles, so it only conducts in thin films,
like rubbing parts would have around contact points. Because it is nonlinear,
'conductivity' is undefined (and the rubbing of bumpy surfaces mean
the film thickness is likewise indefinite). Variants on this lubricant
are recommended for slide potentiometers, I see.

The admixture of conductive particles would make a grease conduct electricity,
but that would be unsafe in electrical panels (and the intended uses include busbars).
It would decalibrate potentiometers, too. Because metallic particles would
constitute dissimilar metals in my mechanism, I didn't want to use such a grease.


If the stuff works as you describe, then it should change conductivity
from a bad insulator to a marginal conductor when pressure is applied.
That got my interest because I have an application for a cheap
pressure sensing system, that will work with rollers and gears. In
theory, I could monitor the conductivity between meshed gears, which
would give me an indication of the applied pressure or changes in
pressure.

However, I don't think it works the way you suggest[1]. The grease
simply prevents surface oxidation and displaces electrolytes to reduce
galavanic corrosion if the mating surfaces are dissimilar meatals.
Doping it with conductive particles also helps reduce galvanic
corrosion. When I read the vague and misleading promotional
literature from that point of view, the claims seems to make sense.

On the other foot, there are specialized greases that allegedly work
the way you describe. I found a hint at:
https://www.linkedin.com/grp/post/1786018-215513373
but could not find any specifics. I'll dig more later. I also
haven't had time to read through the patents yet but I'll get to it
this weekend.


[1] increased pressure = thin film = increased conductivity

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


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Default What is that whiteish stuff on bad batteries (ruins stuff)?

In article ,
Jeff Liebermann wrote:

Can't be, it's transparent. It's based on a semiconductive component, which is nonlinear:
insulating in bulk, but breaks down (in conductivity, not chemical nature) in
thin films under electrical stress. US Patent #4696832 has more info.


Never heard of that stuff, but if it's as you describe, it should be
quite useful. How conductive, I don't know.


This material is better known as "Stabilant 22" (often used as
"Stabilant 22A", diluted in alcohol). Years ago, Stabilant 22A was
remarketed to the audiophile community (in small syringes, probably
with a huge mark-up) under the name "Tweek".

I've used it for quite a few years. It definitely seems to help
maintain electrical connections between contacts. Quite useful for
(e.g.) finger contacts on PCI cards... it has restored reliable
operation for cards which were intermittent, when a simple "unplug,
clean, and re-plug" cycling didn't help.


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Default What is that whiteish stuff on bad batteries (ruins stuff)?

Jeff Liebermann wrote:
On Wed, 19 Aug 2015 01:20:09 -0700 (PDT), whit3rd
wrote:

Yeah, there's a high information cost... and there's more boosterism than
chemical physics in the sales lit. As to 'how conductive', the L260 variant
that I used doesn't have conductive particles, so it only conducts in thin films,
like rubbing parts would have around contact points. Because it is nonlinear,
'conductivity' is undefined (and the rubbing of bumpy surfaces mean
the film thickness is likewise indefinite). Variants on this lubricant
are recommended for slide potentiometers, I see.

The admixture of conductive particles would make a grease conduct electricity,
but that would be unsafe in electrical panels (and the intended uses include busbars).
It would decalibrate potentiometers, too. Because metallic particles would
constitute dissimilar metals in my mechanism, I didn't want to use such a grease.


If the stuff works as you describe, then it should change conductivity
from a bad insulator to a marginal conductor when pressure is applied.
That got my interest because I have an application for a cheap
pressure sensing system, that will work with rollers and gears. In
theory, I could monitor the conductivity between meshed gears, which
would give me an indication of the applied pressure or changes in
pressure.

However, I don't think it works the way you suggest[1]. The grease
simply prevents surface oxidation and displaces electrolytes to reduce
galavanic corrosion if the mating surfaces are dissimilar meatals.
Doping it with conductive particles also helps reduce galvanic
corrosion. When I read the vague and misleading promotional
literature from that point of view, the claims seems to make sense.

On the other foot, there are specialized greases that allegedly work
the way you describe. I found a hint at:
https://www.linkedin.com/grp/post/1786018-215513373
but could not find any specifics. I'll dig more later. I also
haven't had time to read through the patents yet but I'll get to it
this weekend.


[1] increased pressure = thin film = increased conductivity


I still have cramolin copper grease. I never used it on anything. Seems
like it had little conductivity with test leads.

Greg
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