[GreenKeys] KS-7470

[Bob Camp]

Hi

I simply caution that I have had the dreaded “turns into a big glob of rubber” problem when mixing synthetic based oils with petroleum based oils. Neither one was intended as a motor oil. Neither one was ever anticipated to be used anywhere near the other ….The effect was pretty dramatic and nothing you would want to clean back out of a complicated piece of gear. I’m quite sure that when they make motor oil, one of
the criteria is that it mix well with other versions of motor oils. My guess is that was not a requirement on the “wonderful stuff” I happened to pick up. 

Bob

> On Jun 12, 2015, at 7:50 PM, Richard Knoppow <1oldlens1 at ix.netcom.com> wrote:
> 
>    When I did the searching around for a modern equivalent of the grease recommended by Collins Radio I found a couple of articles stating that some air crashes were due to the mixing of synthetic grease with petroleum grease in control gears.   However, a google search about mixing oils produced the following:
> 
> http://chemistry.about.com/od/geochemistry/f/What-Happens-If-You-Mix-Regular-And-Synthetic-Oil.htm
> 
> http://www.valvoline.com/faqs/motor-oil/full-synthetic-motor-oil/
> 
> https://answers.yahoo.com/question/index?qid=20080522152013AAuT6nh
> 
> http://harleytechtalk.org/htt/index.php?topic=7000.0
> 
>     Now, all these say its OK to mix the two types, however this is for OIL.  When I looked for grease compatibility things were not so clear, for instance:
> 
> http://www.machinerylubrication.com/Read/882/mixing-greases
> 
>     I think the difference is that greases have a carrier to hold the oil.  They are meant to be used where plain oil will not be distributed properly or will run off a surface so they are composed of oil in a carrier.  The carriers may not be compatible so its not so simple as with oil.
> 
> 
> On 6/12/2015 4:09 PM, Bob Camp wrote:
>> Hi
>> 
>> Probably worth adding:
>> 
>> Mixing synthetics with petroleum based products can be (but is not always) a problem. Best to try a bit of whatever and see what happens. Watch for separation of the two products.  Also, in extreme cases, watch for gumming.
>> 
>> Bob
>> 
>>> On Jun 12, 2015, at 6:10 PM, Richard Knoppow <1oldlens1 at ix.netcom.com> wrote:
>>> 
>>>    Two possibilities:  One is Microil made by Kano Labs and described as instrument oil.  See their web site for details. Also, most oil companies make "R&O Turbine Oil"   R&O means it has additives to prevent rust and oxidation.   Turbine oil is recommended as a general purpose fine machinery oil, especially for electric motor bearings.  It needs agitation from the bearing so is not a substitute for grease.  There are a number of synthetic greases made for aircraft use under names like Aeroshell No.7.  A grease with similiar specs is specified by Collins Radio for the cams and gear train in the R-390A.   There are also fine synthetic (silocone based) oils and greases available at hobby shops that specialize in model trains.   These do not gum up with age but may not be as good as lubricants as highly refined petroleum based oils like Microil or the turbine oils.   Turbine oils are usually specified with ISO numbers.  No.46 is about equal in viscosity to SAE 20 weight.  Normally, these are sold in 55 gallon drums but are also available in small amounts with some searching.  One source says Grainger carries it.
>>> 
>>> On 6/12/2015 11:24 AM, Jim Haynes wrote:
>>>> Speaking of gumminess, we know that KS-7470 is not really good around the
>>>> plastic tubing that was used in Model 28s to enclose the wire bundles.
>>>> They get noticeably sticky.
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>>> -- 
>>> Richard Knoppow
>>> 1oldlens1 at ix.netcom.com
>>> WB6KBL
>>> 
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>> 
> 
> -- 
> Richard Knoppow
> 1oldlens1 at ix.netcom.com
> WB6KBL
> 
>