Home » Public Forums » GMCnet » Grease Vs Silicon Grease Vs Dielectric Grease
| Grease Vs Silicon Grease Vs Dielectric Grease [message #368563] |
Tue, 25 January 2022 11:56  |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
Grease Vs Silicon Grease Vs Dielectric Grease
We have had Oil Wars and Tire Wars and I am going to fire a salvo into a possible Grease War.....
First, some definitions - sort of:
Grease is a lubricant with a very high pour point temperature, so high that it does not become liquid in many applications.
Pour point is an engineering evaluation of the temperature that a material will migrate (run) of its own accord with gravity only.
All normal lubricating greases are non-conductive, that is to say they are dielectric. Greases that are conductive at all are very special products. I do have some, but it is not out where unknowing people could get at it because the cost of the product will convince you that you don’t want to waste it.
Grease like you might use in most places stays below pour point for the larger part. A good and clear exception is in wheel bearings. In that application, it wants to be able to go liquid if the bearing temperature gets high. If (when) that happens, the excess grease you load into the bearing space can save the day. Most every place else, it stays its sticky self and gets pulled into loaded contact points by just being there near the moving parts. All good greases have a very high film strength, that is to say, they will keep loaded metal surfaces apart. Can you guess why this in not what you want in a connector?
Silicon Grease was a development during WWII and at first aircraft instrument makers thought they had the answer to a lot of their temperature problems. Aircraft at very high altitudes had instrument trouble because the lubricants used would go hard with the low temperatures encountered. Silicon greases did not do not this. They thought that this was the golden grease. Problem: They started doing test and yes, the new stuff did not have low temperature issues, but it was not a good lubricant at all. Things worn out fast. This was needed for control gyros that were critical to fire (as in shooting) control and attitude instruments. Things called Dynamotors were also a constant problem. A dynamotor is a low voltage DC motor turning a high voltage generator. This was a way to get the high voltages needed for the operation of the electronics of the day.
It did have a wonderful application as a film creator to keep things you might want to take apart from sticking together like spark plug boots and as a mold release agent for the manufacture of fiberglass reinforced plastic that were arriving on the scene and bringing a whole new set of manufacturing problems with them.
Now, let’s talk about Dielectric Grease. This comes in two “flavors”. First is just plain grease type. This is what you can use to prevent oxidation in connections. It does wonders for little light bulbs. As this is a non-lubricating grease, it is very effective at limiting exposure of surfaces to elements that may degrade the electrical contacts in connections. At the same time, with its almost non-existent film strength, it will not interfere with the intended connections.
Second is Heat Sink compound. This is just absolutely just silicon grease that had been loaded with something to enhance its thermal conductivity. They is most often use Barium Titanate. That is the White Stuff we put under HEI modules. This is an essential part of many semi-conductor application because the junctions that do all the important work create heat while they are doing what we need. While the heat sink compounds have thermal conductivity that is higher than the plain silicon grease, they may also still be enough dielectric to mess up a connection that is supposed to exist or create one where it should not be.
In case you did not identify that above as the situation under an HEI module, look at the parts and think about it again. Same is true of the voltage regulator in the XXSI series alternators. The mounting screws need to make essential connections to the grounded part of the system, and then there is the big metal area that is the heat sink for the electronics inside. Without that heatsink compound in there, the gap between the frame and the electronics works as what engineers call a “Heat Dam”. This is what you really don’t need to cool the inner workings of the module.
How does Matt know all about this??
His father was developing aircraft systems during that war and he often talked about the interesting discoveries that were made. All I had to do was listen and even though I did not understand everything, I retained enough to ask questions after I finished engineering school.
I will be posting this on both GMCnet and the Forum because these questions have come up both places. If I get any interesting questions (about something I forgot?), I will mirror those.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
|
|
| [GMCnet] Re: Grease Vs Silicon Grease Vs Dielectric Grease [message #368565 is a reply to message #368564] |
Tue, 25 January 2022 13:30  |
Patrick Flowers
Messages: 195
Registered: February 2004
Karma: -24
|
Senior Member |
|
|
On 2022-01-25 13:28, Emery Stora via Gmclist wrote:
> Thanks, Matt.
> Dick Paterson has told me that he uses an electrically conductive
> grease called OxGard.
OxGard is available from your local big box store. It's original
purpose was for use on aluminum wiring. I think you can get it in a 1
oz package now. The 8 oz tube that I have would last me several
lifetimes. Be careful with it tho', it will happily create a short
circuit if you apply too much.
Patrick
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Patrick Flowers
GMCnet Listmaster
'73 CanyonLands
Tyrone, GA
|
|
|
|
| Re: [GMCnet] Re: Grease Vs Silicon Grease Vs Dielectric Grease [message #368566 is a reply to message #368564] |
Tue, 25 January 2022 14:35 |
|
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
stu@97381.com, Emery wrote on Tue, 25 January 2022 13:28Thanks, Matt.
Dick Paterson has told me that he uses an electrically conductive grease called OxGard. He asks I said that the module heat sink grease can run down into the two screws and act to insulate it electrically. The module depends on the grounding through those two screws to operate properly. So, he puts OxGard on the screws when he mounts the module.
Emery Stora
Emery,
Dick is no fool, and come-backs don't help your reputation.
I was unsure as to whether I should try to bring in those connection enhancement sorts. I'm not sure that they qualify as a grease. They are greasy enough.
Oxgard, NOALOX and PENETROX (the only three I have used) all seem be pretty much the same stuff. They start out as lithium based grease but all mention that they use a reduced sulfur stock and then stir in mostly zinc powder. They may have other stuff too, but the plan in that when the join is compressed, the grease and other stuff gets out of the zinc gets left in the connection areas of the joint. The grease prevents exposure and the zine makes the actual connection over more area than would normally be in a dry joint.
Originally, I thought that these were a silicon grease base, but MSDS and consults with a manufacture said otherwise. I guess if you were desperate, you could use it in place of a lithium grease at only about eleven times the cost.
When we played with this, we could get a reading over a short span with a 1kV megger, but no normal meter would report conductivity until the probes actually touched.
I did think about using it in a connector when my silicon grease was not in my kit, but as the connector body was plastic and I did not know how that material would deal with the lithium grease, I got off the ladder and went to get the Dow silicon grease. I don't need come-back either.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
| Re: [GMCnet] Re: Grease Vs Silicon Grease Vs Dielectric Grease [message #368567 is a reply to message #368565] |
Tue, 25 January 2022 14:45 |
|
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
From the GMC Motorhome Forum
pvfjr said:
Good info, Matt. I might add, where you define non-conductive greases, you may want to stipulate that you're talking about electrically non-conductive, particularly as you go on to discuss thermally conductive greases below. It could confuse some folks that don't understand the context.
Paul,
I was aware that this could be an issue, but I was also aware that I have heard people refer to heat sink compound as silicon grease. It is for its major component, but it is a different animal.
Thank You
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
| [GMCnet] Re: Grease Vs Silicon Grease Vs Dielectric Grease [message #368568 is a reply to message #368566] |
Tue, 25 January 2022 15:07 |
k2gkk
Messages: 4452
Registered: November 2009
Karma: -8
|
Senior Member |
|
|
I use Penetrox and NoAlox interchagably to coat
mating surfaces of aluminum elements of directional
amateur radio antennas. It is definitely conductive
and when applied to clean surfaces, allows those
antennas to be taken apart and put back together
easily in a new location. I believe both of these use
powdered aluminum as the electrical carrier.
DX Engineering Co. also has a similar product that
is copper bearing for use in connecting grounding
rods of copper or copper coated steel. I am certain
that electrical supply houses also carry this product.
D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com
________________________________
From: Matt Colie
Sent: Tuesday, January 25, 2022 14:35
To: gmclist@list.gmcnet.org
Subject: [GMCnet] Re: Grease Vs Silicon Grease Vs Dielectric Grease
Emery,
Dick is no fool, and come-backs don't help your reputation.
I was unsure as to whether I should try to bring in those connection enhancement sorts. I'm not sure that they qualify as a grease. They are greasy
enough.
Oxgard, NOALOX and PENETROX (the only three I have used) all seem to be
pretty much the same stuff. They start out as lithium based grease but all
mention that they use a reduced sulfur stock and then stir in mostly zinc
powder. They may have other stuff too, but the plan in that when the join
is compressed, the grease and other stuff gets out of the zinc gets left in
the connection areas of the joint. The grease prevents exposure and the
zine makes the actual connection over more area than would normally be
in a dry joint.
Originally, I thought that these were a silicon grease base, but MSDS and
consults with a manufacture said otherwise. I guess if you were desperate,
you could use it in place of a lithium grease at only about eleven times the cost.
When we played with this, we could get a reading over a short span with a
1kV megger, but no normal meter would report conductivity until the probes
actually touched.
I did think about using it in a connector when my silicon grease was not in
my kit, but as the connector body was plastic and I did not know how that
material would deal with the lithium grease, I got off the ladder and went
to get the Dow silicon grease. I don't need come-back either.
Matt
--
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
|
|
|
|
|
|
| Re: Grease Vs Silicon Grease Vs Dielectric Grease [message #368571 is a reply to message #368569] |
Tue, 25 January 2022 16:53 |
|
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
JohnL455 wrote on Tue, 25 January 2022 17:02Matt maybe I’m all messed up now but don’t you mean silicone grease. Silicon is an element used in semiconductors. A solid at room temp.
John,
You are correct that silicon is an element, so are carbon or hydrogen.
Silicone is the silicon based material than is created by manufactures and these do not exist in nature. Silicon Dioxide is very common we call quartz.
These greases are silicon based as they are not organic in origin.
It is called silicone grease by some, but that is technically incorrect. It has pervaded the vernacular, like so many other things. I suppose you could call it silicone grease, because it is manufactured. Silicon grease is not manufactured using silicone, it is the other way around.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
| Re: Grease Vs Silicon Grease Vs Dielectric Grease [message #368572 is a reply to message #368563] |
Tue, 25 January 2022 17:41 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
|
Senior Member |
|
|
Great. The lexicon has become corrupted by repeated misuse. Much as the current variant is pronounced with the big O sound instead of the small o sound. Micron literally means small. Mega, large.
Now on the rubber compound that tears easily it is silicone. Transistors and diodes, silicon
John Lebetski
Woodstock, IL
77 Eleganza II
|
|
|
|
|
|
|
|
| Re: Grease Vs Silicon Grease Vs Dielectric Grease [message #368582 is a reply to message #368563] |
Wed, 26 January 2022 13:41 |
boybach
Messages: 566
Registered: December 2020
Location: Vancouver Island
Karma: 4
|
Senior Member |
|
|
So where does white lithium grease fall in the scheme of things, Matt?
Larry
Larry - Victoria BC -
1977 ex-Palm Beach "Ol' Leaky" 40,000 miles, PO said everything working but forgot the word NOT. Atwood helium fridge, water heater & furnace. SS exhaust system, Onan, Iota Converter, R134A, New fuel lines & heat exchange hoses
|
|
|
|
|
|
| Re: Grease Vs Silicon Grease Vs Dielectric Grease [message #368586 is a reply to message #368585] |
Wed, 26 January 2022 17:41 |
|
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
Remarks from Paul Ferrigno Jr from GMC Motorhome Forum
Quote: I just noticed something else my brain had just been skipping over and filling in the blanks. You might want to distinguish between silicone (the polymer) and silicon (the element). The words often get used interchangeably, but I would guess only the former applies here.
I do have more questions though, Matt, if you've got the time. I know nothing about film strength properties of different greases. Is a purpose built dielectric grease based on a silicone grease? I had thought they were very closely related, and have seen silicone grease used extensively for the purpose of protecting contacts from oxidation. I've done it extensively myself with no ill effects, but perhaps I've just been lucky?
I've seen silicone grease defined as a silicone oil thickened with a lithium soap, and silicone paste defined as a silicone oil thickened by other inert fillers. Perhaps that's what I've been missing? Would a silicone oil thickened with a lithium base result in the type of silicone grease that has a film strength which would be bad for use on electrical contacts?
My go-to has always been Super Lube. It definitely does a great job protecting contacts, and I've rebuilt a lot of oxidized antique automotive switches and whatnot over the years with it. It's always worked for me, but I'd hate to think I've been adding contact resistance all this time. Perhaps I need to start paying more $$$ for those smaller tubes...
OK Paul,
We had part of the silicon/silicone discussion over on GMCnet, most of that issue seems to be the silicone has replaced silicon in the common vernacular even though this is sometimes incorrect .
About film strengths, real lubricating greases all have some, real silicon grease has virtually none. This is why it is so good in electrical connectors. It simply can't interfere with things making proper contact. If the contact points actually make contact, a silicon grease will not interfere if there is any contact pressure. This is why it is so often referred to as dielectric grease. It will not cause issues in electric contacts buy introducing low resistance.
The silicon grease that is thickened with a lithium soap will could have too much film strength to use in the area of contacts. The real silicon greases that I have used have all been clear and the dry lithium soap that we used in one application was as white as most lithium grease I have seen.
When it comes to a label like Super Lube, my knowledge about their specific products is limited at best. As I recall (iirc) they have a number of products under that label and I would have to look at each to be able to provide a better answer to this question.
From my experience in rebuilding switches (what a PITA with the little balls and springs that try escape), most have enough contact pressure (if you re-assemble it correctly - BTDT) so they will break the film strength of most simple greases. So, most available light greases have not been an issue to me (see note above) that prevented proper operation when the switch was returned to service.
As this has probably not answered all your questions, if you would like another answer, I will do my best with the knowledge that I have. I am not afraid to say when I don't know about something.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
Goto Forum:
Current Time: Wed May 15 04:41:58 CDT 2024
Total time taken to generate the page: 0.00837 seconds
|
GMCforum
Search
Help
Register
Login
Home
