do NOT put Sil-Glyde on Throttle Shaft Bushings!

[mrtwowheel]

Different rubber compounds, lubricants and fluids, and conflicting information on the internet. It's all hit and miss.

Scott

 

[Mailman]

^LOL. How are the diaphragms now? Did it really hurt them? Probably less sensitive than what we're talking about.

They seem to be ok. It’s been awhile since I’ve had my carbs apart. I will be pulling them apart this winter and I’ll have a better idea.

 

[DogBunny]

A lot of good and interesting info posted.
I tried to find the MSDS for the ACE 90% pure silicone grease, but had no luck. But, I did find several diving silcone greases that look promising:

Here is the MSDS:
http://www.tridentdive.com/aalp20.pdf
Contains 100% DIMETHYLPOLYSILOXANE. What the heck is that? Look it up, and maybe you'll stop eating fast food. Here's the wiki:
https://en.wikipedia.org/wiki/Polydimethylsiloxane
I f anyone can understand the above wiki, please share.
Anyways, the jars say for use on o-rings. I think I'm going to try some.

 

[fredintoon]

- - - http://www.redrubbergrease.com/. - - -

Hi 5twins,
In the few months between when my Employer closed the Saskatoon office and when my pension kicked in
I dusted off my 40 year old Rolls-Royce machinist's papers and drove a lathe at a local hydraulic machinery shop.
The foreman tested my skills by having me turn a shaft in a lathe, not mentioning it's 4-jaw independent chuck.
Even after 40 years as a draftsman I still remembered how to center an independent chuck.
Started the next morning.
All of the seals in their hydraulic cylinders were slathered with a purplish red goop on assembly and I always wondered what it was.
And now I know. Thanks.

 

[xjwmx]

All of the seals in their hydraulic cylinders were slathered with a purplish red goop on assembly

I rebuilt some air cylinders and the kit with the rubber seals included a little tube of Magnalube green grease.

 

[TwoManyXS1Bs]

...Contains 100% DIMETHYLPOLYSILOXANE. What the heck is that?

Simply put, that PDMS is THE primary component of silicone oils and greases. Explained in the first paragraph:

https://en.wikipedia.org/wiki/Silicone_grease

I guess a suitable test, for our carb applications, would be to get a whole bunch of various offerings, smear them on glass plates, and expose them (aggressively) to gasoline, gasohol, carb cleaners.

Then see which ones easily wash off...

 

[DogBunny]

Simply put, that PDMS is THE primary component of silicone oils and greases. Explained in the first paragraph:

https://en.wikipedia.org/wiki/Silicone_grease
.

Thank you TwoMany. This is the Wiki article that baffled me:
https://en.wikipedia.org/wiki/Polydimethylsiloxane#Chemical_compatibility
Rather than (or in addition to?) talking about what materials PDMS makes swell, it talks about what chemicals make PDMS itself swell. I guess because PDMS can behave as a solid:
https://en.wikipedia.org/wiki/Polydimethylsiloxane#Mechanical_properties
Bewildering.
In addition to Chemical Compatibilty, we need a paragraph on Rubber Compounds Compatibility. Or maybe it's just assumed to be compatible with rubber compounds?

 

[TwoManyXS1Bs]

That PDMS chain, even tho' it has CH3 hydrocarbons dangling off every elbow, is supposedly quite inert, low reactive, due to the tight bonding facilitated by the silicon core. But, a collection of chains CAN be infiltrated by some other organics (non-polar solvents), but not water (a polar solvent). So, it acts like petro greases, but, due to its inertness, doesn't unwantedly react and infuse itself into adjacent chemicals.

My understanding is that it's inert and safe on all variations of (natural) rubbers.

Beyond that, are the bewildering numbers of tests in those o-ring material compatibility charts...