[T3] Grease and its Base (was RE: [T3] Spring Plates (was RE: [T3] Possible to convert '73 Fasty to use '71 & earlier calipers/discs?))

[Adriel Rowley <adriel_rowley@hotmail.com>]

----------------------------------------
> Date: Thu, 21 Jan 2010 12:10:07 -0600
> From: jadney@vwtype3.org
> Subject: RE: [T3] Spring Plates (was RE: [T3] Possible to convert '73 Fasty to use '71 & earlier calipers/discs?)
> To: type3@vwtype3.org
>
> On 21 Jan 2010 at 8:56, Adriel Rowley wrote:
>
>> I do not own any petroleum grease, so I would have not caused damage,
>
> Just to clarify, unless you've gone out and bought something very special, any
> grease you have is petroleum grease.
>
That has got me thinking.Ê What I have states Lithium based, so I thought that 
meant it was not petroleum based.Ê 

> Grease is actually an homogenized mixture of an oil (which is most commonly a
> petroleum oil) and a thickener which is chemically known as a "soap." The soap
> holds the mixture in place, but the oil does all the lubricating. Over time,
> the oil bleeds out of the soap and gets where you need lubrication. Over a long
> time, you'll find that your grease has lost all its oil and has hardened into a
> useless paste.
>
Found this: http://en.wikipedia.org/wiki/Lithium-based_grease then 
http://en.wikipedia.org/wiki/Stearic_acid.Ê LiOH or Li2CO3Êis reacted with C18H36O2, 
but the result I cannot find (or remember how it is worked out due to being so 
long ago), but is the basis of the Lithium based grease.Ê However, I am then not 
sure how it can be called petrolium based, which is C8H18 especially considering 
the following statement.Ê 

> Different greases are made by choosing different viscosities of oil and 
> different thicknesses of soap. The thickness of the soap determines how long
> the grease will stay in place and the viscosity of the oil determines how
> quickly the oil bleeds out of the grease. Other properties of the oil then
> determine what kinds of lubrication it is most useful for.
>
Would lithium based grease be then not petroleum based, as the petroleum is 
reacted with a metal based compound?

If the case, it would make since, as one does not want the oil separating from 
the soap inside a 500*F bearing. ;|

> The oils that are used are generally petroleum based, but some speciality
> greases ($$$) use silicone oils or synthetic oils.
>
Guess then I should take a closer look at the greases around here; one is 
supposed to be special, but I know not why.Ê The Lithium was fairly expensive, 
I.I.R.C..

> Greases also usually contain additives like corrosion inhibitors and boundary
> layer lubricants like graphite or molybdenum disulfide.
>
Makes since, and good to know. 

> For more information, see:
>
> http://en.wikipedia.org/wiki/Grease_%28lubricant%29
>
That was helpful, especially in the additives, but not answer whether lithium 
based grease is in the class of petroleum based grease.

> or there is very good coverage in the "Machinerys Handbook."
>
No such article by the name, but something similar, but is not for the public.


Thank you,
Adriel
 		 	   		  
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